thioacetamide and Chemical-and-Drug-Induced-Liver-Injury

The endoplasmic reticulum (ER) controls many biological functions besides maintaining the function of liver cells. Various studies reported the role of the ER stress and UPR signaling pathway in various liver diseases via triggering hepatocytes apoptosis. This study aims to investigate the suppressive effect of β-sitosterol (βS) on apoptosis associated with liver injury and ER stress.. Liver damage in rats was induced by TAA (150 mg/kg I.P twice a week/3 weeks) and γ-irradiation (single dose 3.5 Gy) and treated with βS (20 mg/kg daily for 30 days). Serum aminotransferase activity, lipid profile and lipid metabolic factors were measured beside liver oxidative stress and inflammatory markers. Moreover, the hepatic expression of ER stress markers (inositol-requiring enzyme 1 alpha (IRE1α), X-box-binding protein 1 (XBP1) and CCAAT/enhancer binding protein homologous protein (CHOP) and apoptotic markers were detected together with histopathological examination.. βS diminished the aminotransferase activity, the oxidative stress markers as well as the inflammatory mediators. Furthermore, βS lowered the circulating TG and TC and the hepatic lipotoxicity via the suppression of lipogenesis (Srebp-1c) and improved the β-oxidation (Pparα and Cpt1a) together with the mitochondrial biogenesis (Pgc-1 α). Moreover, the upregulated levels of ER stress markers were reduced upon treatment with βS, which consequently attenuated hepatic apoptosis.. βS relieves hepatic injury, ameliorates mitochondrial biogenesis, and reduces lipotoxicity and apoptosis via inhibition of CHOP and ER stress response.

Topics: Animals; Apoptosis; Chemical and Drug Induced Liver Injury; Endoplasmic Reticulum Stress; Endoribonucleases; Hepatocytes; Liver; Protein Serine-Threonine Kinases; Rats; Sitosterols; Thioacetamide; Transaminases

The aim of this study was to investigate the prophylactic and therapeutic effects of Arum dioscoridis (tirsik) plant extract against thioacetamide-induced experimental liver toxicity.. In this study, 35 male Wistar-Albino rats, of 12-14 weeks old, weighing between 200 and 270 g, were used. Rats were divided into 5 groups of 7 each. The first group was determined as the control group, the second group as the hepatotoxicity group, the third group as the prophylaxis group, the fourth group as the intraperitoneal treatment group, and the fifth group as the oral treatment group. Hepatotoxicity was achieved with a single intraperitoneal dose of 350 mg/kg of thioacetamide (TAA). On the seventh day, the rats were sacrificed under general anesthesia. Their blood was taken and liver enzymes were studied. Malondialdehyde (MDA), glutathyon peroxi dase (GPx), catalase (CAT), superoxit dismutase (SOD) enzymes were studied from liver tissues. In addition, liver tissues were evaluated histopathologically.. With Arum dioscoridis treatment and prophylaxis, improvements in all parameters and increases in tissue antioxidant levels were detected.. It was determined that Arum dioscoridis plant extract has prophylactic and therapeutic effects on liver toxicity. In cases of acute liver injury and hepatotoxicity, we suggest the potential application of Arum dioscoridis for effective and inexpensive treatment.

Topics: Animals; Antioxidants; Arum; Chemical and Drug Induced Liver Injury; Liver; Oxidative Stress; Plant Extracts; Rats; Rats, Wistar; Thioacetamide

The protective effect of biochanin A (BCA) on the histopathology, immunohistochemistry, and biochemistry of thioacetamide (TAA)-induced liver cirrhosis in vivo was investigated. There was a significant reduction in liver weight and hepatocyte propagation, with much lower cell injury in rat groups treated with BCA (25 mg/kg and 50 mg/kg) following a TAA induction. These groups had significantly lower levels of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA). The liver homogenates showed increased antioxidant enzyme activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as decreased malondialdehyde (MDA) levels. The serum biomarkers associated with liver function, namely alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma glutamyl transaminase (GGT), returned to normal levels, comparable to those observed in both the normal control group and the reference control group. Taken together, the normal microanatomy of hepatocytes, the inhibition of PCNA and α-SMA, improved antioxidant enzymes (SOD, CAT, and GPx), and condensed MDA with repairs of liver biomarkers validated BCA's hepatoprotective effect.

Topics: Alanine Transaminase; Animals; Antioxidants; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Liver; Liver Cirrhosis; Oxidative Stress; Proliferating Cell Nuclear Antigen; Rats; Rats, Wistar; Superoxide Dismutase; Thioacetamide

Topics: Acrylates; Animals; Antioxidants; Becaplermin; Chemical and Drug Induced Liver Injury; Fibrosis; Glutathione; Glutathione Disulfide; Glutathione Peroxidase; Glutathione Reductase; Imidazoles; Inflammation; Liver; Male; Mangifera; Oxidative Stress; Quercetin; Rats; Rats, Wistar; Superoxide Dismutase; Thioacetamide; Thiophenes; Tumor Necrosis Factor-alpha

This study aimed at investigating the chemical composition and the hepatoprotective activities of Plumbago indica L. and P. auriculata Lam. LC-MS/MS analyses for the hydroalcoholic extracts of the aerial parts of the two Plumbago species allowed the tentative identification of thirty and twenty-five compounds from P. indica and P. auriculata, respectively. The biochemical and histopathological alterations associated with thioacetamide (TAA)-induced liver fibrosis in rats were evaluated in vivo where rats received the two extracts at three different dose levels (100, 200 and 400 mg/kg p.o, daily) for 15 consecutive days with induction of hepatotoxicity by TAA (200 mg/kg/day, i.p.) at 14th and 15th days. Results of the present study showed a significant restoration in liver function biomarkers viz. alanine transaminase (ALT), aspartate transaminase (AST), gamma glutamyl transferase and total bilirubin. The liver homogenates exhibited increased levels of antioxidant biomarkers: reduced glutathione (GSH) and catalase (CAT), accompanied with decline in malondialdehyde (MDA). Furthermore, treated groups exhibited a significant suppression in liver inflammatory cytokines: tumor necrosis factor-α (TNF-α) and interlukin-6 (IL-6), and fibrotic biomarker: alpha smooth muscle relaxant. Histopathological examination of the liver showed normality of hepatocytes. Noteworthy, P. indica extract showed better hepatoprotective activity than P. auriculata, particularly at 200 mg/kg. To sum up, all these results indicated the hepatoprotective properties of both extracts, as well as their antifibrotic effect was evidenced by reduction in hepatic collagen deposition. However, additional experiments are required to isolate their individual secondary metabolites, assess the toxicity of the extracts and explore the involved mechanism of action.

Topics: Animals; Antioxidants; Biomarkers; Chemical and Drug Induced Liver Injury; Chromatography, Liquid; Liver; Liver Cirrhosis; Oxidative Stress; Phytochemicals; Plant Extracts; Plumbaginaceae; Rats; Rats, Wistar; Tandem Mass Spectrometry; Thioacetamide

To study the complex processes involved in liver injuries, researchers rely on animal investigations, using chemically or surgically induced liver injuries, to extrapolate findings and infer human health risks. However, this presents obvious challenges in performing a detailed comparison and validation between the highly controlled animal models and development of liver injuries in humans. Furthermore, it is not clear whether there are species-dependent and -independent molecular initiating events or processes that cause liver injury before they eventually lead to end-stage liver disease. Here, we present a side-by-side study of rats and guinea pigs using thioacetamide to examine the similarities between early molecular initiating events during an acute-phase liver injury. We exposed Sprague Dawley rats and Hartley guinea pigs to a single dose of 25 or 100 mg/kg thioacetamide and collected blood plasma for metabolomic analysis and liver tissue for RNA-sequencing. The subsequent toxicogenomic analysis identified consistent liver injury trends in both genomic and metabolomic data within 24 and 33 h after thioacetamide exposure in rats and guinea pigs, respectively. In particular, we found species similarities in the key injury phenotypes of inflammation and fibrogenesis in our gene module analysis for liver injury phenotypes. We identified expression of several common genes (e.g., SPP1, TNSF18, SERPINE1, CLDN4, TIMP1, CD44, and LGALS3), activation of injury-specific KEGG pathways, and alteration of plasma metabolites involved in amino acid and bile acid metabolism as some of the key molecular processes that changed early upon thioacetamide exposure and could play a major role in the initiation of acute liver injury.

Topics: Animals; Biomarkers; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Gene Expression Profiling; Gene Regulatory Networks; Guinea Pigs; Liver; Male; Metabolome; Metabolomics; Rats, Sprague-Dawley; Species Specificity; Thioacetamide; Time Factors; Transcriptome

In patients, advanced cirrhosis only regresses partially once the etiological agent is withdrawn. Animal models for advanced cirrhosis regression are missing. Lifestyle interventions (LIs) have been shown to improve steatosis, inflammation, fibrosis, and portal pressure (PP) in liver disease. We aimed at characterizing cirrhosis regression after etiological agent removal in experimental models of advanced cirrhosis and to study the impact of different LI on it. Advanced cirrhosis was induced in rats either by carbon tetrachloride (CCl

Topics: Animals; Caloric Restriction; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Energy Intake; Exercise Therapy; Healthy Lifestyle; Hypertension, Portal; Liver; Liver Cirrhosis, Experimental; Male; Physical Endurance; Rats, Wistar; Risk Reduction Behavior; Thioacetamide; Time Factors

The intention to conduct this study was to evaluate the hepatoprotective effects of Fenugreek seeds' extract supplementation in thioacetamide induced liver damage in male Sprague Dawley rats. For this study, 24 male Sprague Dawley rats (200-264gm) were distributed randomly into four groups. Group I remained untreated as control rats, group II received thioacetamide (200mg/Kg b.w i.p, administered on alternative days for 8 weeks), group III received thioacetamide (200mg/Kg b.w i.p administered on alternative days for 8 weeks) as well as 2ml of 2% extract of fenugreek seeds (orally administered daily from 4th week till 8th week of the experiment. Group IV only received 2ml of 2% extract of Fenugreek seeds daily for 4 weeks respectively. At the end of the experiment, blood was sampled to obtain plasma that was used for the analysis of liver markers and liver was used for analysis of antioxidant enzymes (catalase and SOD). Increase in total bilirubin, direct bilirubin, ALT and ALP levels, catalase activity and decrease in SOD activity was found in TAA-treated groups which assured liver damage. Whereas, treatment with Fenugreek seeds extract restored the altered levels of total bilirubin, direct bilirubin, ALT, ALP, catalase and SOD activities in the Test + Supp group. The results of this study confirmed the hepatoprotective role of Fenugreek seeds extract in thioacetamide induced liver damage.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Antioxidants; Bilirubin; Body Weight; Catalase; Chemical and Drug Induced Liver Injury; Liver; Organ Size; Plant Extracts; Random Allocation; Rats; Superoxide Dismutase; Thioacetamide; Trigonella

The purpose of this study was to determine whether abscisic acid (ABA) can protect against liver fibrosis induced by thioacetamide (TAA) in vivo by inhibiting apoptosis and inflammatory responses. To this end, three times per week, mice were injected intraperitoneally with TAA (200 mg/kg) for 8 weeks to induce liver fibrosis. After the fourth week of treatment, histological changes, the serum biochemical index, inflammation, and hepatocyte apoptosis factors (e.g., caspase-3, B-cell lymphoma 2 [Bcl-2], Bcl-2-associated X [Bax]) were detected to clarify its underlying mechanism. The results clearly indicated that ABA improves TAA-induced hepatic injury and collagen accumulation in mice. Otherwise, ABA significantly reduced liver fibrosis by regulating caspase-3 and Bcl-2, α-smooth muscle actin, and collagen I. ABA inhibited the nuclear factor kappa B pathway, significantly alleviating oxidative stress and inflammatory cytokines. Therefore, ABA may be a potential therapeutic agent for preventing liver damage.

Topics: Abscisic Acid; Actins; Animals; Anti-Inflammatory Agents; Antioxidants; Apoptosis; Caspase 3; Chemical and Drug Induced Liver Injury; Collagen Type I; Inflammation Mediators; Interleukin-1beta; Liver; Liver Cirrhosis, Experimental; Male; Mice; NF-kappa B; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Thioacetamide; Tumor Necrosis Factor-alpha

Macrophage migration inhibitory factor (MIF) is a multipotent cytokine that contributes to the inflammatory response to chemical liver injury. This cytokine exhibits pro- and anti-inflammatory effects depending on the etiology and stage of liver disease.. Our study aimed to investigate the role of MIF in oxidative stress and inflammation in the liver, and modulatory effects of betaine on MIF in thioacetamide (TAA)-induced chronic hepatic damage in mice.. The experiment was performed on wild type and knockout MIF-/- C57BL/6 mice. They were divided into the following groups: control; Bet-group that received betaine (2% wt/v dissolved in drinking water); MIF-/- mice group; MIF-/-+Bet; TAA-group that received TAA (200 mg/kg b.w.), intraperitoneally, 3x/week/8 weeks); TAA+Bet; MIF-/-+TAA, and MIF-/-+TAA+Bet. In TAA- and Bet-treated groups, animals received the same doses. After eight weeks of treatment, blood samples were collected for biochemical analysis, and liver specimens were prepared for the assessment of parameters of oxidative stress and inflammation.. In MIF-/-mice, TAA reduced transaminases, γ-glutamyltranspeptidase, bilirubin, malondialdehyde (MDA), oxidative protein products (AOPP), total oxidant status (TOS), C-reactive protein (CRP), IL-6, IFN-γ, and increased thiols and total antioxidant status (TAS). Betaine attenuated the mechanism of MIF and mediated effects in TAA-induced liver injury, reducing transaminases, γ-glutamyltranspeptidase, bilirubin, MDA, AOPP, TOS, CRP, IL-6, IFN-g, and increasing thiols.. MIF is a mediator in hepatotoxic, pro-oxidative, and proinflammatoryeffects of TAA-induced liver injury. MIF-targeted therapy can potentially mitigate oxidative stress and inflammation in the liver, but the exact mechanism of its action requires further investigation. Betaine increases anti-oxidative defense and attenuates hepatotoxic effects of MIF, suggesting that betaine can be used for the prevention and treatment of liver damage.

Topics: Animals; Betaine; Chemical and Drug Induced Liver Injury; Chemical and Drug Induced Liver Injury, Chronic; Inflammation; Liver; Macrophage Migration-Inhibitory Factors; Mice; Mice, Inbred C57BL; Oxidative Stress; Thioacetamide

Liver cirrhosis is the main chronic liver disease and is considered a catabolic disease. Cirrhotic patients have a low energy intake and high energy expenditure at rest, leading to metabolic disorders. Malnutrition is associated with complications of cirrhosis and has been shown that a nutritional intervention with increase of energy intake improves the survival of cirrhotic patients. Therefore, our aim was to evaluate the effect of a high sucrose diet in the liver of animals with cirrhosis induced by thioacetamide and investigate the mechanism involved.. Male Wistar rats were divided into three groups: Control; Thioacetamide; and Thioacetamide + high sucrose diet. The thioacetamide was administrated (100 mg kg. The administration of thioacetamide was associated with fibrosis and inflammatory infiltrate in the liver and increased levels of transaminases enzymes. The high sucrose diet promoted a reduction of theses parameters in cirrhotic rats. The malnutrition observed in cirrhotic rats was attenuated by the high sucrose diet shown by the improvements in weight loss, subcutaneous fat, and caloric intake. The high sucrose diet also attenuated the oxidative stress present in the liver of animals with thioacetamide-induced cirrhosis.. The high sucrose diet had anti-inflammatory and anti-oxidant effects in the liver of animals with thioacetamide-induced cirrhosis. In addition, the high sucrose diet also improved malnutrition and catabolism present in cirrhosis. Thus, a high sucrose diet may be a therapeutic option for cirrhotic patients in a catabolic state.

Topics: Animals; Chemical and Drug Induced Liver Injury; Diet; Dietary Sucrose; Inflammation; Liver; Liver Cirrhosis; Liver Cirrhosis, Experimental; Male; Oxidative Stress; Rats; Rats, Wistar; Sucrose; Thioacetamide

Topics: Animals; Chemical and Drug Induced Liver Injury; Liver; Neutrophils; Rats; Rats, Inbred F344; Rodent Diseases; Thioacetamide

Chronic liver injury is characterised by continuous or repeated epithelial cell loss and inflammation. Hepatic wound healing involves matrix deposition through activated hepatic stellate cells (HSCs) and the expansion of closely associated Ductular Reactions and liver progenitor cells (LPCs), which are thought to give rise to new epithelial cells. In this study, we used the murine thioacetamide (TAA) model to reliably mimic these injury and regeneration dynamics and assess the impact of a recovery phase on subsequent liver injury and fibrosis. Age-matched naïve or 6-week TAA-treated/4-week recovered mice (C57BL/6 J, n = 5-9) were administered TAA for six weeks (C57BL/6 J, n = 5-9). Sera and liver tissues were harvested at key time points to assess liver injury biochemically, by real-time PCR for fibrotic mediators, Sirius Red staining and hydroxyproline assessment for collagen deposition as well as immunofluorescence for inflammatory, HSC and LPC markers. In addition, primary HSCs and the HSC cell line LX-2 were co-cultured with the well-characterised LPC line BMOL and analysed for potential changes in expression of fibrogenic mediators. Our data demonstrate that recovery from a previous TAA insult, with LPCs still present on day 0 of the second treatment, led to a reduced TAA-induced disease progression with less severe fibrosis than in naïve TAA-treated animals. Importantly, primary activated HSCs significantly reduced pro-fibrogenic gene expression when co-cultured with LPCs. Taken together, previous TAA injury established a fibro-protective molecular and cellular microenvironment. Our proof-of principle HSC/LPC co-culture data demonstrate that LPCs communicate with HSCs to regulate fibrogenesis, highlighting a key role for LPCs as regulatory cells during chronic liver disease.

Topics: Animals; Cells, Cultured; Chemical and Drug Induced Liver Injury; Coculture Techniques; Disease Models, Animal; Hepatic Stellate Cells; Liver; Liver Cirrhosis; Liver Regeneration; Male; Mice; Mice, Inbred C57BL; Stem Cells; Thioacetamide

MicroRNAs (miRNA) have received considerable attention as potential biomarkers for drug-induced liver injury. We recently reported that the plasma levels of miR-143-3p and miR-218a-5p increased in severe cholestasis in rats. This study aimed to investigate whether these miRNAs increase in a severity-dependent manner and to elucidate their pathophysiological roles in cholestasis. Male Sprague-Dawley rats were orally administered different doses of α-naphthylisothiocyanate or 4,4-methylenedianiline to induce acute cholestasis. They were also orally administered acetaminophen or thioacetamide to induce hepatocellular injury. We found that plasma miR-143-3p and miR-218a-5p levels increased in a dose-dependent manner in cholestatic rats but not in hepatocellular injury. Bioinformatic analysis provided putative target genes of hsa-miR-218-5p, rno-miR-218a-5p, and mmu-miR-218-5p, among which GNAI2, PPP1CB, and PPP2R5A were experimentally validated as their direct target genes in human cholangiocyte line MMNK-1. Proliferation of MMNK-1 cells was significantly suppressed after overexpression of miR-218-5p and transduction of siRNAs for GNAI2, PPP1CB, and PPP2R5A. In the cholestatic livers of rats, Ppp1cb and Ppp2r5a expression levels decreased, whereas Gnai2 expression levels increased compared with those in vehicle-treated rats, suggesting that Ppp1cb and Ppp2r5a may be under the control of miR-218a-5p in vivo. In conclusion, our data suggest that miR-218(a)-5p is involved in the suppression of cholangiocyte proliferation by inhibiting the expression of PPP1CB and PPP2R5A, thereby contributing to the pathogenesis of cholestasis; and miR-218a-5p leaks into the plasma probably from damaged cholangiocytes in a severity-dependent manner in rats. Therefore, miR-218a-5p overexpression could be one of the underlying mechanisms of acute cholestatic liver injury in rats.

Topics: Acetaminophen; Animals; Biomarkers; Chemical and Drug Induced Liver Injury; Cholestasis; Disease Models, Animal; Humans; Isothiocyanates; Male; MicroRNAs; Rats; Rats, Sprague-Dawley; Thioacetamide

The water-soluble acidic polysaccharide from Thalassodendron ciliatum (Forss.) den Hartog was successfully extracted, fractionated and purified. The phytochemical profile of the two water-soluble fractions (F1 and F2), were detected using different analytic techniques. GC-MS analysis revealed the presence of 22 saccharide. Acidic polysaccharide, galacturonic and glucuronic acid were the most abundant. Moreover, paper chromatography and electrophoresis also performed as a preliminary chemical characterization of the polymer. The hepatoprotective activity of the fractions against thioacetamide (TAA) induced liver failure; antioxidant potential and preliminary immunomodulatory activity were assigned in-vivo. The results revealed a potent competence to improve the liver function profile (ALT, AST, total bilirubin, total glyceride, etc.) and a remarkable improvement in liver architecture in comparison to the challenged intoxicated groups. Moreover, they showed high anti-oxidative properties and a promising immunomodulatory influence via Il6. These findings provide new insight into the possible role of polysaccharide purified two fractions in the treatment of acute liver injury.

Topics: Animals; Chalcones; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Gas Chromatography-Mass Spectrometry; Glycosides; Liver Failure; Male; Polysaccharides; Rats; Rats, Wistar; Thioacetamide

The normal functioning of Kelch-like ECH-associated protein-1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) complex is necessary for the cellular protection against oxidative stress. We investigated the effect of chlorogenic acid (CGA), quercetin (Qt), coenzyme Q10 (Q10) and silymarin on the expression of Keap1/Nrf2 complex and its downstream target; heme oxygenase-1 (HO-1) as well as inflammation and apoptosis in an acute liver toxicity model induced by thioacetamide (TAA).. Wistar rats were divided into 13 groups: Control, silymarin, CGA, Qt, Q10, TAA (single dose 50 mg/kg, i.p.), TAA + silymarin (400 mg/kg, p.o.), TAA + CGA (100 & 200 mg/kg, p.o.), TAA + Qt (200 &300 mg/kg, p.o.) and TAA+ Q10 (30&50 mg/kg, p.o.) and treated for 8 days.. The results showed improved liver functions and hepatic tissue integrity in all tested doses of TAA + silymarin, TAA + CGA, TAA + Qt and TAA + Q10 groups compared to the TAA group. Furthermore, these groups showed significantly lower ROS, malondialdehyde and nitric oxide levels but higher glutathione content and superoxide dismutase activity compared to the TAA group, p < 0.05. In these groups, Keap1 expression was significantly decreased while Nrf2 expression and HO-1 activity were increased. In addition, the number of apoptotic cells and the expression level of TNF-α in the liver tissues were significantly decreased compared to the TAA group.. CGA, Qt, Q10 and silymarin protect against TAA-induced acute liver toxicity via antioxidant, anti-inflammatory, anti-apoptotic activities and regulating Keap1-Nrf2/HO-1 expression.

Topics: Animals; Chemical and Drug Induced Liver Injury; Chlorogenic Acid; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; Kelch-Like ECH-Associated Protein 1; Liver; Male; NF-E2-Related Factor 2; Quercetin; Rats; Rats, Wistar; Signal Transduction; Silymarin; Thioacetamide; Ubiquinone

Macrophages contribute to liver fibrogenesis by the production of a large variety of cytokines. ATF6 is associated with the activation of macrophages. The present study aimed to investigate the role of ATF6 in the expression of macrophage-derived cytokines and liver fibrogenesis after acute liver injury. Following thioacetamide (TAA)-induced acute liver injury, the characteristics of the occurrence of liver fibrosis and the secretion of cytokines by macrophages were first described. Then, the role of various cytokines secreted by macrophages in activating hepatic stellate cells (HSCs) was tested in vitro. Finally, endoplasmic reticulum stress (ER-stress) signals in macrophages were detected following liver injury. siRNA was used to interfere with the expression of ATF6 in macrophages to verify the influence of ATF6 on cytokine expression and liver fibrogenesis after liver injury. A single intraperitoneal injection of TAA induced acute liver injury. The depletion of macrophages attenuated acute liver injury, while it inhibited liver fibrogenesis. During acute liver injury, macrophages secrete a variety of cytokines. Most of these cytokines promoted the activation of HSCs, but the effect of IL-1α was most significant. In the early stage of acute liver injury, ER-stress signals in macrophages were activated. Interference of ATF6 expression suppressed the secretion of cytokines by macrophages and attenuated liver fibrogenesis. Overall, in the early stage of acute liver injury, ATF6 signals promoted the expression of macrophage-derived cytokines to participate in liver fibrogenesis, and IL-1α exhibited the most significant role in promoting the activation of HSCs and liver fibrogenesis.

Topics: Activating Transcription Factor 6; Animals; Cells, Cultured; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Endoplasmic Reticulum Stress; Gene Expression Regulation; Humans; Interleukin-1alpha; Liver; Liver Cirrhosis; Macrophage Activation; Macrophages; Mice; Mice, Inbred C57BL; RNA, Small Interfering; Thioacetamide

Morinda elliptica L. (Rubiaceae) is a phytomedicinal herb, used to treat gastrointestinal complications in Peninsular Malaysia. The study evaluates the in vivo hepatoprotective activity of ethanolic extract of M. elliptica stem in thioacetamide (TAA) induced liver fibrosis in male Sprague Drawly rats. Thirty adult rats were divided into five groups of six rats each. Rats of the normal control group received intraperitoneal injections (i. p.) of vehicle 10% Tween-20, 5 ml/kg, and hepatotoxic group 200 mg/kg TAA three times per week respectively. Three supplementary groups were treated with TAA plus daily oral silymarin (50 mg/kg) or M. elliptica (250 or 500 mg/kg). After 8 weeks of treatment, all rats were sacrificed. Liver fibrosis was assessed by gross macroscopic and microscopic tissue analysis, histopathological, and biochemical analysis. The livers of the TAA treated group showed uniform coarse granules, hepatocytic necrosis with lymphocytes infiltration. Contrary, the livers of M. elliptica treated groups (250 and 500 mg/kg) were much smoother and the cell damage was much lesser. The livers of M. elliptica treated groups rats showed elevated activity of SOD and CAT with a significant decrease in MDA level at p < .0001. The level of liver damage parameters, that is, ALP, ALT, and AST, bilirubin, total protein, and albumin were restored to the normal comparable to silymarin. M. elliptica stem extract significantly promoted normal rat liver architecture with significant perfections in biochemical parameters. The molecular contents of M. elliptica with hepatoprotective influence could be discovered, is the future prospective of this study.

Topics: Animals; Chemical and Drug Induced Liver Injury; Liver; Liver Cirrhosis; Morinda; Plant Extracts; Rats; Rats, Wistar; Thioacetamide

Depression is a highly prevalent mental disease and increasingly become a global public health problem. Recent studies have shown that the dysfunction of liver was associated with depression. However, the previous studies have not been fully explained the relationship between depression and liver injury. The present study was aimed to investigate whether chronic liver injury could induce depressive-like behavior. Chronic liver injury was induced by intraperitoneal injection of carbon (CCl

Topics: Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Depression; Female; Galactosamine; Hindlimb Suspension; Hippocampus; Liver; Male; Mice; Swimming; Thioacetamide

Acute or chronic damage to the liver may occur through alcohol, drugs, viruses, genetic disorders, and toxicity. In this study, we planned to investigate the protective and therapeutic effects of melatonin (Mel) by causing damage to the liver with thioacetamide (TAA). Thirty-five rats were used. Group I: control group (seven pieces), group II: Mel group (seven pieces) the single dose on the first day of the experiment was 10 mg/kg, group III: TAA (seven pieces) 300 mg/kg with 24-hour intervals, two doses, group IV: Mel + TAA group (seven pieces) 10 mg/kg single dose Mel was applied 24  hours before TAA application, group V: TAA + Mel group (seven pieces) single dose (24th hour) of 10 mg/kg Mel was administered after TAA (300 mg/kg) two doses. The liver histology was evaluated. Apoptosis, autophagy, and necrosis markers in tissue were determined by immunohistochemistry. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) levels in blood serum samples and transforming growth factor-β (TGF-β) and tumor necrosis factor-α (TNF-α) levels were determined in liver tissue. TAA affected histologically the classical lobule structure both in cell cords and sinusoids. Caspase-3, RIP3, and LC3 levels were increased in group III compared with the control group. TAA did not cause a statistically significant change in TNF-α level but decreased the TGF-β level significantly. AST and ALT levels were statistically significant in group II and V compared with group I, the ALP level was significant in group IV compared with group II. The results of this study showed that TAA caused significant damage to tissues and increased cell death, Mel was found to have more therapeutic than the protective effect on tissues.

Topics: Acute Disease; Alanine Transaminase; Alkaline Phosphatase; Animals; Antioxidants; Aspartate Aminotransferases; Caspase 3; Chemical and Drug Induced Liver Injury; Immunohistochemistry; Liver; Lymphotoxin-alpha; Male; Melatonin; Microtubule-Associated Proteins; Oxidative Stress; Rats; Rats, Wistar; Receptor-Interacting Protein Serine-Threonine Kinases; Thioacetamide; Tumor Necrosis Factor-alpha

This study aimed to investigate the protective effect of water extracts of Orychophragmus violaceus seeds on liver injury induced by thioacetamide(TAA) in mice. ICR male mice were randomly divided into seven groups: normal group, model group, bicyclol positive control group(200 mg·kg~(-1)), Kuihua Hugan Tablets group(350 mg·kg~(-1)), O. violaceus seeds low-dose water extract group(125 mg·kg~(-1)), middle-dose water extract group(250 mg·kg~(-1)), and high-dose water extract group(500 mg·kg~(-1)). Intragastric administration was given in all groups at 0.02 mL·g~(-1) body weight, 1 time a day for continuous 4 days. One h after the administration on the 4 th day, the liver injury model was induced by intraperitoneal injection of TAA(100 mg·kg~(-1)). The mice were put to death 24 hours later. Blood and tissues were taken and organ indexes were calculated. The activities of ALT, AST and TBiL in serum were detected. The content of MDA, GSH and the activity of SOD, GSH-Px in liver homogenate were examined by colorimetry method. HE staining was used to observe the pathological changes of liver tissues in mice. The protein expression levels of NF-κB p65, Keap-1, Nrf2, p-p38, p-JNK, p-ERK, Bax, Bcl-2, caspase-3, cleaved caspase-3 and caspase-8 were detected by Western blot. The results showed that as compared with the model group, various O. violaceus seeds groups could significantly improve the pathological conditions of liver and reduce ALT, AST, TBiL activities in serum of mice with liver injury. In the high-dose group, the activities of SOD, GSH-Px and the content of GSH were significantly increased, while MDA content was sharply declined. Meanwhile, O. violaceus seeds extract down-regulated the expressions of Bax, Keap-1, p-p38, p-JNK, p-ERK, NF-κB p65, cleaved caspase-3 and up-regulated the expressions of Nrf2, Bcl-2, caspase-3 and caspase-8. In conclusion, O. violaceus seeds extract exhibited potent protective effect on liver injury induced by TAA in mice, and its mechanism may be related to down-regulating levels of Keap-1, up-regulating the expressions of Nrf2, inhibiting the expressions of p-p38, p-ERK and NF-κB p65 signaling pathway, and inhibiting hepatocyte apoptosis by down-regulating the expressions of p-JNK and Bax and up-regulating the expressions of Bcl-2.

Topics: Animals; Apoptosis; Brassicaceae; Chemical and Drug Induced Liver Injury; Liver; Male; Mice; Mice, Inbred ICR; Oxidative Stress; Plant Extracts; Seeds; Signal Transduction; Thioacetamide

Retinoid receptors (RRs), RAR-α and RXR-α, work as transcription factors that regulate cell growth, differentiation, survival, and death. Hepatic stellate cells (HSCs) store retinoid and release its RRs as lipid droplets upon their activation.. We test the hypothesis that loss of retinoid receptors RAR-α and RXR-α from HSCs is dependent on tissue factor (TF) during thioacetamide (TAA)-induced liver injury.. Liver toxicity markers, TF, fibrin, cleaved caspase-3, and cyclin D1 as well as histopathology were investigated.. Increased TF, fibrin, cleaved caspase-3, and cyclin D1 protein expression is seen in zone of central vein after TAA injection compared with vehicle-treated mice. A strong downregulation of RAR-α and RXR-α is seen in TAA-induced liver injury. In addition, histopathological obliteration and pericentral expression of cleaved caspase 3 and cyclin D1 are observed after TAA injection compared with the normal vehicle-treated mice. No changes have been seen in TAA/TF-sense (SC) in whole parameters compared with TAA-treated animals. TAA/TF-antisense (AS)-treated mice show normal expression of all parameters and normal histopathological features when compared with the control mice. In conclusion, this study declares that the strong downregulation of RAR-α and RXR-α may cause liver injury and particularly activation of HSCs in TAA-induced toxicity. TF-AS treatment not only downregulates TF protein expression but also alleviates loss of liver RAR-α and RXR-α and suppresses the activated apoptosis signals in TAA-induced liver toxicity. Finally, TF and RAR-α/RXR-α are important regulatory molecules in TAA induced acute liver injury.

Topics: Animals; Chemical and Drug Induced Liver Injury; Male; Mice; Nuclear Receptor Subfamily 1, Group F, Member 1; Oligonucleotides, Antisense; Retinoid X Receptor alpha; Thioacetamide; Thromboplastin

Adefovir dipivoxil (AD), a nucleoside reverse transcriptase inhibitor is effective against Hepatitis B virus. Its poor oral bioavailability leads to frequent administration causing severe adverse effects. Thereby the entrapment of AD within lipid nanoparticulate systems is a way of increasing AD oral bioavailability as a result of improving intestinal permeability with efficient liver-targeted delivery together with higher drug stability during storage.. AD-loaded nanostructured lipid carriers (AD-NLCs) were prepared via solvent emulsification diffusion technique adopting 2. Formula (F12) showed E.E.% of 90.5 ± 0.2%, vesicle size of 240.2 ± 2.5 nm and Q8hrs of 58.55 ± 9.4% was selected as the optimum formula with desirability value of 0.757 based on highest EE%, lowest P.S. and Q8hrs. Further evaluation of the optimized formula using radioiodinated rose bengal (RIRB) in thioacetamide induced liver damage in Swiss Albino mice revealed a higher liver uptake of 22 ± 0.01% ID/g (percent injected dose/g organ) and liver uptake/Blood (T/B) ratio of 2.22 ± 0.067 post 2 h of I.V injection of RIRB compared to 9 ± 0.01% ID/g and 0.64 ± 0.017 in untreated group, respectively.. NLCs could be successfully used as oral drug delivery carriers of the antiviral drug Adefovir Dipivoxil to the liver with higher stability and oral bioavailability. Graphical abstract.

Topics: Adenine; Administration, Oral; Animals; Chemical and Drug Induced Liver Injury; Drug Stability; Injections, Intravenous; Iodine Radioisotopes; Lipids; Liver; Liver Function Tests; Mice; Nanoparticles; Organophosphonates; Particle Size; Rose Bengal; Thioacetamide

HSCs (hepatic stellate cells) contribute to the excessive extracellular matrix (ECM) deposition, inflammatory pathways and crucial cell-cell interactions in hepatic disease leading to fibrosis. P2x7R is considered a potential orchestrater in liver fibrosis. For this reason, this work explored the role of P2x7R in liver fibrosis and the mechanism by which P2x7R in macrophages promotes fibrogenesis. In a model of liver fibrosis induced by administration of thioacetamide (TAA), inhibition of P2x7R with its selective inhibitor A438079 reversed TAA-induced liver damage and fibrosis. The mechanism was linked to inhibition of P2x7R-NLRP3 inflammasome activation and thereby infiltration of macrophages and neutrophils into the liver. This result indicated that the P2x7R-TLR4-NLRP3 axis is involved in the process of TGF-β-mediated ECM deposition in HSCs. Ectopic overexpression of P2x7R lowered the threshold of extracellular matrix (ECM) deposition and maintained HSCs in an activated state. The culture medium of THP-1 macrophages stimulated by LPS/ATP aggravated ECM deposition in HSCs by activating P2x7R. Additionally, IL-1β secreted by LPS / ATP activated macrophages amplified fibrosis. These data indicate that P2x7R plays a key regulative role in the activation and maintenance of HSCs promoted by macrophages. Thus, pharmacological inhibition of P2x7R could be a potential therapeutic mechanism to treat human liver fibrosis.

Topics: Animals; Cell Culture Techniques; Cell Line, Tumor; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Extracellular Matrix; Feedback, Physiological; Hepatic Stellate Cells; Humans; Liver Cirrhosis; Macrophages, Peritoneal; Male; Mice; Mice, Inbred C57BL; Purinergic P2X Receptor Antagonists; Pyridines; Receptors, Purinergic P2X7; Tetrazoles; Thioacetamide

Saikosaponin d (SSd), a primary active component of the Chinese herb Bupleurum falcatum, has antitumor and antiliver fibrosis effects. However, the toxicity of SSd at high doses can induce conditions such as metabolic disorders and hemolysis in vivo, thus hampering its clinical use. The present study investigated the toxicity-reducing effects of liposome encapsulation of pure SSd and the therapeutic action of SSd-loaded liposomes (Lipo-SSd) in liver fibrosis in vitro and in vivo. Lipo-SSd (diameter, 31.7 ± 7.8 nm) was prepared at an entrapment efficiency of 94.1%. After 10-day incubation, a slow release profile of 56% SSd from Lipo-SSd was observed. The IC50 of SSd on hepatic stellate cells was approximately 2.9 μM. Lipo-SSd exhibited much lower cytotoxicity than did pure SSd. In the in vivo toxicity assay, Lipo-SSd significantly increased mice survival rate and duration compared with pure SSd at the same dose. These in vitro and in vivo data indicate that liposomal encapsulation can reduce the cytotoxicity of SSd. The histopathological analysis results demonstrated that in mice with thioacetamide-induced liver fibrosis, Lipo-SSd exerted more obvious fibrosis- and inflammation-alleviating and liver tissue-reparative effects than did pure SSd; these effects are potentially attributable to the sustained release of SSd. In conclusion, Lipo-SSd fabricated here have antiliver fibrosis effects and lower toxicity compared with that of pure SSd.

Topics: Animals; Apoptosis; Cell Line; Cell Survival; Chemical and Drug Induced Liver Injury; Delayed-Action Preparations; Dose-Response Relationship, Drug; Drug Compounding; Drug Liberation; Hepatic Stellate Cells; Humans; Inhibitory Concentration 50; Liposomes; Liver; Liver Cirrhosis, Experimental; Male; Mice, Inbred C57BL; Oleanolic Acid; Protective Agents; Saponins; Thioacetamide

Topics: Animals; Behavior Rating Scale; Body Weight; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Drug Discovery; Flavonoids; Glial Fibrillary Acidic Protein; Heme Oxygenase-1; Hepatic Encephalopathy; Humans; Interleukin-6; Liver; Magnoliopsida; Male; Molecular Docking Simulation; Neurotransmitter Agents; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Plant Extracts; Plant Leaves; Rats; Rats, Wistar; Signal Transduction; Thioacetamide

Topics: Administration, Oral; Animals; Antioxidants; Bilirubin; Chemical and Drug Induced Liver Injury; Cholesterol; DNA Damage; Drug Administration Schedule; Glutathione; Interleukin-6; Liver; Male; Malondialdehyde; Metal Nanoparticles; Mustard Plant; Nitric Oxide; Oxidative Stress; Plant Extracts; Rats; Rats, Wistar; Silver; Superoxide Dismutase; Thioacetamide; Triglycerides; Tumor Necrosis Factor-alpha

Oxidative stress induces damages of various cell types or tissues through a repetitive imbalance between the systemic manifestation of reactive oxygen species (ROS) and detoxification of the reactive intermediates. Thioacetamide (TAA) is well known for causing several degenerative diseases by oxidative stress. However, study of the antioxidant mechanisms of stem cells in TAA-injured rat model is insufficient. Therefore, we investigated the effect of placenta-derived mesenchymal stem cells (PD-MSCs) transplantation on liver and ovary of TAA-injured rat models to study the antioxidant effect in degenerative diseases. In TAA-injured rat model, PD-MSCs engrafted into damaged organ including liver and ovary in PD-MSCs transplanted groups (Tx) compared with non-transplanted groups (NTx) (*

Topics: Albumins; Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Female; Heme Oxygenase (Decyclizing); Humans; Inflammation; Liver; Liver Regeneration; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; NADPH Oxidase 4; Ovary; Oxidative Stress; Placenta; Pregnancy; Rats; Reactive Oxygen Species; Regeneration; Thioacetamide

The present study was designed to determine the hepatoprotective effects of fenugreek seeds extract supplementation on thioacetamide induced liver damage in rats. For this purpose 24 male Sprague Dawley rats were distributed into 4 groups (n=60. Group I remained untreated throughout the study. Group II and Group III received thioacetamide intraperitoneally 200mg/kg body weight on alternative days for 8 weeks. Group III and Group IV received 2ml of 2% Fenugreek seeds extract orally daily from 4th week till 8th week of the study. Next day after completion of study, the rats were weighted and decapitated; blood was collected for plasma for glucose and lipid profile analysis. Marked reduced plasma glucose level and HDL level and increased triglyceride, cholesterol, LDL, VLDL and total lipid level were observed in test group. The Fenugreek seeds extract supplementation significantly increased plasma glucose and HDL level and remarkably decreased triglyceride, cholesterol, LDL, VLDL and total lipid level in Test+Supplement group whereas glucose and lipid profile were reduced in supplement group showing supplement is hypoglycemic and hypolipidemic. The results of this study confirmed that treatment with Fenugreek seeds extract successively ameliorates the altered glucose and lipid profile in liver damage induced by thioacetamide in male rats.

Topics: Animals; Biomarkers; Blood Glucose; Chemical and Drug Induced Liver Injury; Dietary Supplements; Disease Models, Animal; Lipids; Liver; Male; Plant Extracts; Protective Agents; Rats, Sprague-Dawley; Seeds; Thioacetamide; Trigonella

The aim of our study is to estimate the hepatoprotective effects of the ethanolic extract of the leaves of

Topics: Animals; Chemical and Drug Induced Liver Injury; Chromatography, High Pressure Liquid; Culture Media; Flavonoids; Liver; Liver Diseases; Male; Mice; Phenols; Plant Extracts; Plant Leaves; Protective Agents; Rats, Wistar; Sequoia; Thioacetamide; Tissue Culture Techniques

Cassia fistula L. (Caesalpinioideae) is a highly admirable medicinal plant and is traditionally recommended for the treatment of rheumatism, liver disorders, jaundice, and other inflammatory diseases. This study was designed to investigate the hepatoprotective properties of ethyl acetate fraction from C. fistula leaves in an animal model. Treatment with thioacetamide significantly elevated the level of serum glutamic-oxaloacetic transaminase (1.75-fold), alkaline phosphatase (4.07-fold), and total bilirubin (2.29-fold) as compared to the control. It was found that pretreatment of fraction followed by consecutive 2 days thioacetamide reduced the conversion of thioacetamide carcinogen to its reactive metabolites by phase I enzymes and increased the level of detoxification phase II along with antioxidative enzymes. The histopathological studies revealed the hepatoprotective nature of the fraction in restoring the normal architecture of thioacetamide-intoxicated damaged liver. The fraction showed downregulation in the expression level of p-PI3K, p-Akt, and p-mTOR pointing towards its chemopreventive potential. The HPLC analysis of the fraction had shown the dominance of three phenolic compounds namely, catechin, epicatechin, and chlorogenic acid. The above studies comprising histopathological, immunohistochemical, and hepatic enzymes are strong indicative of the potential protective ability of ethyl acetate fraction phytoconstituents against thioacetamide-induced toxicity. Graphical abstract.

Topics: Animals; Antioxidants; Aspartate Aminotransferases; Cassia; Chemical and Drug Induced Liver Injury; Liver; Liver Function Tests; Male; Oxidative Stress; Phenols; Plant Extracts; Plant Leaves; Rats, Wistar; Thioacetamide

Hepatic fibrosis is a reversible would-healing response following chronic liver injury of different aetiologies and represents a major worldwide health problem. Up to date, there is no satisfactory drugs treated for liver fibrosis. The present study was to investigate hepatoprotection of yangonin against liver fibrosis induced by thioacetamide (TAA) in mice and further to clarify the involvement of farnesoid X receptor (FXR) in vivo and in vitro. Yangonin treatment remarkably ameliorated TAA-induced liver injury by reducing relative liver weight, as well as serum ALT and AST activities. Moreover, yangonin alleviated TAA-induced accumulation of bile acids through increasing the expression of bile acid efflux transporters such as Bsep and Mrp2, and reducing hepatic uptake transporter Ntcp expression, all of these are FXR-target genes. The liver sections stained by H&E indicated that the histopathological change induced by TAA was improved by yangonin. Masson and Sirius red staining indicated the obvious anti-fibrotic effect of yangonin. The mechanism of anti-fibrotic effect of yangonin was that yangonin reduced collagen content by regulating the genes involved in hepatic fibrosis including COL1-α1 and TIMP-1. Besides, yangonin inhibited hepatic stellate cell activation by reducing TGF-β1 and α-SMA expression. In addition, yangonin protected against TAA-induced hepatic inflammation via its inhibition of NF-κB and TNF-α. These hepatoprotective effects of yangonin were abrogated by guggulsterone which is a FXR antagonist. In vitro experiment further demonstrated dose-dependent activation of FXR by yangonin using dual-luciferase reporter assay. In summary, yangonin produces hepatoprotection against TAA-induced liver fibrosis via FXR activation.

Topics: Animals; Chemical and Drug Induced Liver Injury; Cytokines; Hep G2 Cells; Humans; Liver; Liver Cirrhosis; Male; Mice, Inbred C57BL; Pregnenediones; Protective Agents; Pyrones; Receptors, Cytoplasmic and Nuclear; Thioacetamide

The current study was conducted to evaluate the ameliorative and protective potentials of Moringea oleifera leaves ethanolic extract (MOLE) against thioacetamide (TAA) toxicity. A total of 58 male albino rats were randomly assigned into six experimental groups. G1, rats received distilled water. G2, rats were injected with a single dose of TAA (200 mg/kg BW) i.p. G3, rats were given MOLE (300 mg/kg BW) orally for 26 days. G4, rats were injected TAA as in G2 and treated with MOLE as G3. G5, rats were kept for 26 days without treatment then on day 27 injected with TAA as in G2. G6, rats were given MOLE for 26 days then on day 27 injected with TAA. Phytochemical analysis of MOLE indicated the presence of kaempferol, kaempferol malonylglucoside, kaempferol hexoside, kaempferol -3-O-glucoside, kaempferol-3-O-acetyl-glucoside, cyanidin -3-O-hexoside, ellagic acid, quercetin, quercetin-3-O-glucoside, and apigenin glucoside. Intoxication of rats with TAA significantly elevated activities of serum AST, ALT, and ALP; concentrations of malondialdehyde, nitric oxide, and hepatic tissue protein expression of caspase 3 and COX2 with alteration of the histological structures of hepatic tissues, while it decreased serum levels of total protein, albumin, and hepatic tissue contents of reduced glutathione. Also, TAA intoxication resulted in 62.5% mortality in rats of G5. Treatment of TAA intoxicated rats (G4) with MOLE ameliorated the toxic effects of TAA on hepatic tissue structure and function. It decreased serum activities of AST, ALT, and ALP; enhanced hepatic GSH concentration; reduced pathological alterations and lipid peroxidation; and downregulated caspase 3 and COX2 proteins expression in hepatic tissue. In addition, MOLE protected rats of G6 from TAA-induced hepatic tissues injury and dysfunction, and increased survival rate of rats. In conclusion, MOLE had both ameliorating and protecting potentials against TAA-induced rats liver damage through regulation of antioxidant, anti-apoptotic, and inflammatory biomarkers. Graphical abstract.

Topics: Animals; Antioxidants; Biomarkers; Chemical and Drug Induced Liver Injury; Glucosides; Glutathione; Lipid Peroxidation; Liver; Male; Malondialdehyde; Moringa oleifera; Plant Extracts; Plant Leaves; Protective Agents; Quercetin; Rats; Rats, Wistar; Thioacetamide

Thrombocytopenia is usually associated with liver injury, elevated plasma aspartate aminotransferase and alanine aminotransferase levels, and high antiplatelet immunoglobulin (Ig) titers, although the mechanism behind these effects remains elusive. Deciphering the mechanism behind acute liver disease-associated thrombocytopenia may help solve difficulties in routine patient care, such as liver biopsy, antiviral therapy, and surgery. To determine whether liver damage is sufficient per se to elicit thrombocytopenia, thioacetamide (TAA)-induced hepatitis rodent models were employed. The analysis results indicated that TAA treatment transiently induced an elevation of antiplatelet antibody titer in both rats and mice. B-cell-deficient (BCD) mice, which have loss of antibody expression, exhibited markedly less thrombocytopenia and liver damage than wild-type controls. Because TAA still induces liver damage in BCD mice, this suggests that antiplatelet Ig is one of the pathogenic factors, which play exacerbating role in the acute phase of TAA-induced hepatitis. TNF-α was differentially regulated in wild-type versus BCD mice during TAA treatment, and anti-TNF treatment drastically ameliorated antiplatelet Ig induction, thrombocytopenia, and liver injury, suggesting that the TNF pathway plays a critical role in the disease progression.

Topics: Animals; Antigens, Human Platelet; Autoantibodies; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Disease Progression; Humans; Male; Mice; Rats; Thioacetamide; Thrombocytopenia; Tumor Necrosis Factor-alpha

Cilostazol, a phosphodiesterase 3 inhibitor (PDE3I), is a platelet aggregation inhibitor and vasodilator that is useful for treating intermittent claudication. Experimental studies have shown that cilostazol has potent anti-inflammatory, anti-oxidant effects effects.. Although the hepatoprotective effect cilostazol has been studied, the molecular mechanisms of such protection, including: the nuclear factor-erythroid 2-related factor 2 (Nrf2) / hemoxygenase (HO-1) and the phosphoinositide 3-kinase (PI3K) /serine/threonine kinase (Akt) pathways are not fully explored, which is the aim of this study.. To achieve the aim of this study, 35 rats were grouped into: control groups, liver injury group (model- non treated: injected with thioacetamide (TAA), 150 mg/kg, i.p.), and two cilostazoltreated groups (treated with cilostazol 10 and 50 mg/kg, p.o.). The rats were treated for 8 days and injected with TAA on the 7th day of the experiment and sacrificed 48 hours after TAA injection.. The model group showed evidence of liver injury as indicated by the elevation of liver enzymes and confirmed by histopathological findings. TAA-induced liver injury was accompanied by down-regulation of the cytoprotective pathways: PI3K/Akt and Nrf2/HO-1 mRNAs. Cilostazol administration ameliorated TAA-induced liver injury, where it caused a significant improvement in the activity of liver enzymes as well as in the histopathological changes. Such an effect was associated with a significant increase in the expression of PI3K/Akt and Nrf2/HO-1 mRNAs as detected by Real-time reverse transcription polymerase chain reaction (RT-PCR).. Cilostazol protected rats against TAA hepatotoxicity through up-regulation of PI3K/Akt and Nrf2/HO-1 gene expression.

Topics: Animals; Chemical and Drug Induced Liver Injury; Cilostazol; Heme Oxygenase (Decyclizing); Male; NF-E2-Related Factor 2; Phosphatidylinositol 3-Kinases; Phosphodiesterase 3 Inhibitors; Proto-Oncogene Proteins c-akt; Rats; Thioacetamide; Treatment Outcome

Previous research suggested that insulin-like growth factor binding protein related protein 1 (IGFBPrP1), as a novel mediator, contributes to hepatic fibrogenesis. Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) play an essential role in hepatic fibrogenesis by regulating homeostasis and remodeling of the extracellular matrix (ECM). However, the interaction between IGFBPrP1 and MMP/TIMP is not clear. The present study was to knockdown IGFBPrP1 to investigate the correlation between IGFBPrP1 and MMP/TIMP in hepatic fibrosis.. Hepatic fibrosis was induced by thioacetamide (TAA) in mice. Knockdown of IGFBPrP1 expression by ultrasound-targeted microbubble destruction-mediated CMB-shRNA-IGFBPrP1 delivery, or inhibition of the Hedgehog (Hh) pathway by cyclopamine treatment, was performed in TAA-induced liver fibrosis mice. Hepatic fibrosis was determined by hematoxylin and eosin and Sirius red staining. Hepatic expression of IGFBPrP1, α-smooth muscle actin (α-SMA), transforming growth factor β 1 (TGFβ1), collagen I, MMPs/TIMPs, Sonic Hedgehog (Shh), and glioblastoma family transcription factors (Gli1) were investigated by immunohistochemical staining and Western blotting analysis.. We found that hepatic expression of IGFBPrP1, TGFβ1, α-SMA, and collagen I were increased longitudinally in mice with TAA-induced hepatic fibrosis, concomitant with MMP2/TIMP2 and MMP9/TIMP1 imbalance and Hh pathway activation. Knockdown of IGFBPrP1 expression, or inhibition of the Hh pathway, reduced the hepatic expression of IGFBPrP1, TGFβ1, α-SMA, and collagen I and re-established MMP2/TIMP2 and MMP9/TIMP1 balance.. Our findings suggest that IGFBPrP1 knockdown attenuates liver fibrosis by re-establishing MMP2/TIMP2 and MMP9/TIMP1 balance, concomitant with the inhibition of hepatic stellate cell activation, down-regulation of TGFβ1 expression, and degradation of the ECM. Furthermore, the Hh pathway mediates IGFBPrP1 knockdown-induced attenuation of hepatic fibrosis through the regulation of MMPs/TIMPs balance.

Topics: Actins; Animals; Chemical and Drug Induced Liver Injury; Collagen Type I; Gene Knockdown Techniques; Insulin-Like Growth Factor Binding Proteins; Liver; Liver Cirrhosis, Experimental; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; NIH 3T3 Cells; Signal Transduction; Thioacetamide; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Transforming Growth Factor beta1

Liver fibrosis can progress to cirrhosis, hepatocellular carcinoma, or liver failure. Unfortunately, the antifibrotic agents are limited. Thrombin activates hepatic stellate cells (HSCs). Therefore, we investigated the effects of a direct thrombin inhibitor, dabigatran, on liver fibrosis.. Adult male Sprague-Dawley rats were injected intraperitoneally with thioacetamide (TAA, 200 mg/kg twice per week) for 8 or 12 weeks to induce liver fibrosis. The injured rats were assigned an oral gavage of dabigatran etexilate (30 mg/kg/day) or vehicle in the last 4 weeks of TAA administration. Rats receiving an injection of normal saline and subsequent oral gavage of dabigatran etexilate or vehicle served as controls.. In the 8-week TAA-injured rats, dabigatran ameliorated fibrosis, fibrin deposition, and phosphorylated ERK1/2 in liver, without altering the transcript expression of thrombin receptor protease-activated receptor-1. In vitro, dabigatran inhibited thrombin-induced HSC activation. Furthermore, dabigatran reduced intrahepatic angiogenesis and portal hypertension in TAA-injured rats. Similarly, in the 12-week TAA-injured rats, a 4-week treatment with dabigatran reduced liver fibrosis and portal hypertension.. By inhibiting thrombin action, dabigatran reduced liver fibrosis and intrahepatic angiogenesis. Dabigatran may be a promising therapeutic agent for treatment of liver fibrosis.

Topics: Animals; Antithrombins; Cell Line; Chemical and Drug Induced Liver Injury; Collagen; Cytoprotection; Dabigatran; Extracellular Signal-Regulated MAP Kinases; Fibrin; Hepatic Stellate Cells; Hypertension, Portal; Liver; Liver Cirrhosis, Experimental; Male; Neovascularization, Pathologic; Phosphorylation; Portal Pressure; Rats, Sprague-Dawley; Thioacetamide

Injecting MSCs via blood vessel is most commonly used method, which has a major drawback of safety. The aim of our study was to evaluate efficacy using scaffold-loaded MSCs in acute liver failure model.. Acute liver failure was induced in mice using thioacetamide (TAA) (200 mg/kg, i.p) once a day for two consecutive days. The animals were divided in four acute liver failure groups: (1) TAA; (2) empty scaffold; (3) MSCs injected through tail vein; (4) MSC + Scaffold, scaffold loaded with MSCs, to evaluate the mortality and changes in liver function. Polylactic-co-glycolic acid scaffold alone and loaded with human MSCs was implanted on mice dorsum.. TAA dose was titrated until one-third mortality rate was achieved. TAA (200 mg/kg) once daily for two consecutive days was injected to establish the acute liver failure model. The mortality of TAA and scaffold groups was 55.9% and 63.2%, respectively. Although, mortality of MSC-TV group decreased 14.7% as compared to TAA group (p = 0.200), MSC + Scaffold group had the lowest mortality (31.4%) (p = 0.013). Cells implanted in PLGA biomaterial were survived until 3 weeks, and their function was increased. Area of hepatic inflammation and necrosis was significantly reduced in MSC-TV and MSC + Scaffold groups; but there was no difference between the two groups. Gene expressions related to inflammation were significantly decreased in MSC-TV and MSC + Scaffold groups compared to TAA group. In MSC + Scaffold group, no migration of stem cells to liver tissue was observed. Although, not all cells in scaffold were stained, some of them were differentiated into hepatocyte-like cells which stained positive for PAS and CYP2E1 antibody.. Scaffold loaded with MSCs showed protective effects via paracrine signaling on acute liver failure model.

Topics: Animals; Biomarkers; Cell Differentiation; Cell Movement; Cell Proliferation; Cells, Cultured; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2E1; Disease Models, Animal; Humans; Liver; Liver Failure, Acute; Liver Regeneration; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice, Inbred C57BL; Necrosis; Paracrine Communication; Phenotype; Polylactic Acid-Polyglycolic Acid Copolymer; Thioacetamide; Tissue Scaffolds

Liver is a precious organ to maintain body life. Hepatotoxicity is a worldwide health problem that is still a challenge for research. Although countless pharmaceutical drugs and herbal compounds were screened for their hepatoprotective effects, the death from hepatotoxicity is increasing. Thus, there is continuous necessity of searching for the hepatoprotective effect of commonly used drugs. Accordingly, our aim was to examine a hepatoprotective potential for the antihypertensive drug, verapamil, and searching for new insights underlie its protective mechanism. Four groups of adult male rats were randomly arranged as controls, thioacetamide (TAA) hepatotoxic, and TAA + verapamil treated. Serum liver enzyme, hepatic antioxidant, lipid peroxidation, and inflammatory parameters were assessed. Gene relative expression for heme oxygenase-1 (HO-1), nuclear factor-erythroid 2-related factor 2 (Nrf2), phosphoinositide 3-kinase (PI3K), and serine/threonine-specific protein kinase (Akt) were quantified in hepatic tissue. TAA caused hepatic injury evident both histopathologically and biochemically by a decrease in all gene expressions. Verapamil alleviated the injury via its antioxidant and anti-inflammatory effects that were suggested to be via upregulation of the previous gene expressions. In conclusion, the calcium channel blocker, verapamil, that is used widely as antihypertensive exhibits a valuable hepatoprotective effect. The protection partially rests on activation of Nrf2/HO-1 and PI3K/Akt pathways.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Calcium Channel Blockers; Chemical and Drug Induced Liver Injury; Heme Oxygenase (Decyclizing); Liver; Male; NF-E2-Related Factor 2; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Thioacetamide; Verapamil

For the clinical application of stem cell therapy, functional enhancement is needed to increase the survival rate and the engraftment rate. The purpose of this study was to investigate functional enhancement of the paracrine effect using stem cells and hepatocyte-like cells and to minimize stem cell homing by using a scaffold system in a liver disease model.. A microporator was used to overexpress Foxa2 in adipose tissue-derived stem cells (ADSCs), which were cultured in a poly(lactic-co-glycolic acid) (PLGA) scaffold. Later, the ADSCs were cultured in hepatic differentiation medium for 2 weeks by a 3-step method. For. Foxa2-overexpressing ADSCs showed greater increases in hepatocyte-specific gene markers (alpha fetoprotein [AFP], cytokeratin 18 [CK18], and albumin), cytoplasmic glycogen storage, and cytochrome P450 expression than cells that underwent the conventional differentiation method.. Foxa2-overexpressing ADSCs applied in a scaffold system enhanced hepatocyte-like differentiation and attenuated acute liver damage in an acute liver injury model without homing effects.

Topics: Albumins; alpha-Fetoproteins; Animals; Biocompatible Materials; Cell Differentiation; Cells, Cultured; Chemical and Drug Induced Liver Injury; Connexins; Cytochrome P-450 Enzyme System; Dipeptidyl Peptidase 4; Electroporation; Gap Junction beta-1 Protein; Glycogen; Hepatocyte Nuclear Factor 3-beta; Hepatocytes; Keratin-18; Liver; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Nude; Plasmids; Polylactic Acid-Polyglycolic Acid Copolymer; Thioacetamide; Tissue Scaffolds

Stevioside is a diterpenoid obtained from the leaves of Stevia rebaudiana (Bertoni) that exhibits antioxidant, antifibrotic, antiglycemic and anticancer properties. Therefore, we aimed to study whether stevioside has beneficial effects in liver injury induced by long-term thioacetamide (TAA) administration and investigated the possible underlying molecular mechanism using in vivo, in vitro and in silico approaches.. Liver injury was induced in male Wistar rats by TAA administration (200 mg/kg), intraperitoneally, three times per week. Rats received saline or stevioside (20 mg/kg) twice daily intraperitoneally. In addition, cocultures were incubated with either lipopolysaccharide or ethanol. Liver injury, antioxidant and immunological responses were evaluated.. Chronic TAA administration induced significant liver damage. In addition, TAA upregulated the protein expression of nuclear factor (NF)-κB, thus increasing the expression of proinflammatory cytokines and decreasing the antioxidant capacity of the liver through downregulation of nuclear erythroid factor 2 (Nrf2). Notably, stevioside administration prevented all of these changes. In vitro, stevioside prevented the upregulation of several genes implicated in liver inflammation when cocultured cells were incubated with lipopolysaccharide or ethanol. In silico assays using tumor necrosis factor receptor (TNFR)-1 and Toll-like receptor (TLR)-4-MD2 demonstrated that stevioside docks with TNFR1 and TLR4-MD2, thus promoting an antagonistic action against this proinflammatory mediator.. Collectively, these data suggest that stevioside prevented liver damage through antioxidant activity by upregulating Nrf2 and immunomodulatory activity by blocking NF-κB signaling.

Topics: Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Computer Simulation; Diterpenes, Kaurane; Glucosides; Immunologic Factors; In Vitro Techniques; Male; Oxidative Stress; Rats; Rats, Wistar; Signal Transduction; Sweetening Agents; Thioacetamide

Sitagliptin is an oral hypoglycemic drug that acts by selective inhibition of dipeptidyl peptidase-4 (DDP-4) enzyme.. This study scrutinized the hepatoprotective impact of sitagliptin) against thioacetamide (TAA)-induced liver damage in mice.. Male mice were injected with TAA (500 mg/kg) then treated with sitagliptin (20 mg/kg) orally for 5 days.. Histopathological results of TAA group revealed severe degree of centrolobular hepatic necrosis. Additionally, biochemical findings showed marked elevation in the serum transaminases and gamma glutamyl transpeptidase (GGT) levels in TAA group. Injection of TAA significantly disrupted oxidant/antioxidants hemostasis of the hepatic tissues. Also, TAA markedly increased the expression of nuclear factor kappa-B (NF-KB); and enhanced Toll like receptor 4 (TLR4) as well as NLPR3 inflammosome production. Moreover, there was an elevation in the hepatic levels of tumor necrosis factor-alpha (TNF-α) and interleukin -1 beta (IL-1β) besides increased immunoexpression of Bcl-2-associated X protein (Bax) as well as caspase 3. In contrast, treatment with sitagliptin significantly attenuated TAA-induced histopathological, biochemical and immunohistochemical alterations.. Our results suggest that the hepatoprophylactic impact of sitagliptin might be arbitrated via modulating TLR4 and NK-KB signaling cascade followed by depression of inflammation besides apoptosis.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Chemical and Drug Induced Liver Injury; Dipeptidyl-Peptidase IV Inhibitors; Liver; Male; Mice; NF-kappa B; Oxidative Stress; Signal Transduction; Sitagliptin Phosphate; Thioacetamide; Toll-Like Receptor 4

The liver performs a variety of essential functions; hence drug-induced liver injury (DILI) is a serious concern that can ultimately lead to the withdrawal of a drug from the market or discontinuation of drug development. However, the mechanisms of drug-induced liver injury are not always clear. We hypothesized that drugs may inhibit the liver recovery process, especially bile canalicular (BC) network reformation, leading to persistent liver injury and deterioration, and tested this hypothesis in the present work. The BC structure disappeared in mice following treatment with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) or thioacetamide (TAA) for 4 weeks, then reappeared after 4 weeks of receiving a normal diet. By contrast, reconstruction of the BC structure was suppressed in mice fed a diet containing 0.3% benzbromarone (BBR; which can induce fatal liver injury in clinical settings) after liver injury. Plasma ALT levels were increased significantly in mice treated with BBR after DDC or TAA treatment, compared with BBR alone. To confirm whether BBR has a direct inhibitory effect on hepatocytes, we also examined BC reformation in primary cultured mouse hepatocytes with a sandwich configuration. Under these culture conditions, the BC network rapidly reformed from days 2 and 3 after seeding. During the reformation period, BBR inhibited BC reformation significantly. These results suggest that BBR inhibits BC reconstruction and delays recovery from pre-existing liver injury.

Topics: Alanine Transaminase; Animals; Benzbromarone; Cells, Cultured; Chemical and Drug Induced Liver Injury; Hepatocytes; Liver; Male; Mice, Inbred C57BL; Pyridines; Thioacetamide

Acute liver injury caused by toxins or drugs is a common condition that threatens patients' lives. Inositol-requiring enzyme 1 alpha (IRE1α), the most conserved endoplasmic reticulum (ER) stress sensor, has been implicated in the pathophysiology of liver injury. Activated IRE1α endoribonuclease (RNase) can splice X-box binding protein 1 (XBP1) mRNA to produce the sXBP1 transcription factor. STF-083010, a specific inhibitor of IRE1α RNase, has recently been suggested to exhibit anti-oxidant and anti-inflammatory properties in multiple injury models. However, it remains unknown whether STF-083010 has a protective effect against thioacetamide (TAA)-induced acute liver injury. Here, we demonstrated that IRE1α-sXBP1 signaling is involved in the development of TAA-induced acute liver injury and correlates with the severity of liver damage. STF-083010 protected against TAA-induced liver injury, as evidenced by higher survival rates in response to a lethal dose of TAA and less severe liver injury in response to a toxic dose of TAA. Mechanistic exploration showed that STF-083010 triggered hepatocyte autophagy in response to TAA stimulation both in vivo and in vitro, leading to reduced reactive oxygen species (ROS) production and attenuated hepatic inflammation. We also found that Beclin-1 played a critical role in STF-083010-mediated autophagy in response to TAA stimulation. Autophagy inhibition by chloroquine (CQ) in vivo and Beclin-1 knockdown in vitro markedly abrogated the protective role of STF-083010 against TAA-induced oxidative stress, inflammation and hepatotoxicity. Our results suggested STF-083010 as a potential therapeutic application to prevent TAA-induced acute liver injury.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Autophagy; Cells, Cultured; Chemical and Drug Induced Liver Injury; Cytokines; Endoribonucleases; Hepatocytes; Male; Mice, Inbred C57BL; Oxidative Stress; Protein Serine-Threonine Kinases; Reactive Oxygen Species; Sulfonamides; Thioacetamide; Thiophenes

1,25 Dihydroxyvitamin D. TAA caused severe damage, increased lipid peroxidation with reductions in endogenous antioxidants, increased apoptosis, increased production of reactive oxygen species, and elevated inducible nitric oxide synthase (iNOS), and nuclear factor kappa B (NF-κB) expression in liver. Extent of damage was decreased by 1,25(OH). 1,25(OH)

Topics: Animals; Apoptosis; Calcitriol; Chemical and Drug Induced Liver Injury; Drug Evaluation, Preclinical; Female; Liver; Random Allocation; Rats, Sprague-Dawley; Thioacetamide

Liver cirrhosis is a scene profitable to the advance of hepatocellular carcinoma (HCC). The current work was engrossed to weigh the potential role of Cichorium intybus linn against thioacetamide (TAA)-induced liver cirrhosis and their probable underlying biochemical and molecular mechanisms. farnesoid-X-receptor (FXR) expression, proliferating cell nuclear antigen (PCNA) immunoreactivity, and activated AMP protein kinase (pAMPK), sirtuin-1 (SIRT1), and interleukin-6 (IL6) levels were estimated in hepatic tissue by real-time PCR, immunohistochemistry, and immunoassay, respectively. C. intybus linn supplementation caused a significant improvement in serum liver enzymes, albumin, bilirubin levels, tissues redox status and hepatic histological features in addition to decreased IL6 level, hydroxylproline content, and PCNA immunoreactivity. On contrary, increased pAMPK/SIRT1 levels and upregulated FXR gene expression were observed. C. intybus linn could feasibly protect against TAA-induced hepatic damage, fibrosis, and cirrhosis by relieving oxidative stress and by interruption of the inflammatory pathway via AMPK/SIRT1/FXR signaling. PRACTICAL APPLICATIONS: No specific therapies are available until now to target the underlying mechanisms for protection against liver diseases. Herbal protection is widely available and cheap with no side effect. Cichorium intybus linn, a natural supplement, is proved in this current work to have the potential of being hepatoprotectant, antioxidant, and anti-inflammatory agents, thus reducing the risk of hepatic cirrhosis.

Topics: Adenylate Kinase; Animals; Body Weight; Cell Proliferation; Chemical and Drug Induced Liver Injury; Cichorium intybus; Dietary Supplements; Gene Expression Regulation; Hepatocytes; Inflammation; Liver; Liver Cirrhosis; Male; Organ Size; Oxidation-Reduction; Proliferating Cell Nuclear Antigen; Rats; Receptors, Cytoplasmic and Nuclear; RNA, Messenger; Signal Transduction; Sirtuin 1; Thioacetamide

Our previous works showed that dioscin, a natural product, could protect liver from acute liver damages induced by dimethylnitrosamine, ethanol, carbon tetrachloride and acetaminophen. However, the effect of dioscin on thioacetamide (TAA)-induced acute liver injury still remained unknown. The purpose of this study was to investigate whether dioscin confers a protective effect against TAA-induced acute liver injury in rats and mice. The results showed that dioscin decreased the serum levels of ALT, AST, and rehabilitated histopathological changes compared with the model groups. In addition, dioscin obviously increased the levels of GSH, GSH-Px, SOD, and significantly reduced MDA levels compared with the model groups. Mechanistic study showed that dioscin significantly up-regulated the expression levels of FXR, p-AMPKα, and then increased the expression levels of Nrf2, HO-1, NQO-1, GCLM and GST. Furthermore, dioscin obviously down-regulated the expression levels of NF-κB (p65), ICAM-1, HMGB1, COX-2, TNF-α, IL-1β and IL-6. Taken together, dioscin showed protective effect against TAA-induced acute liver injuries in rats and mice and the effects might be obtained through inhibiting oxidative stress and inflammation via FXR/AMPK signal pathway. These findings provided a new insight on the role of doscin in the treatment of acute liver injury.

Topics: AMP-Activated Protein Kinases; Animals; Chemical and Drug Induced Liver Injury; Diosgenin; Dose-Response Relationship, Drug; Male; Mice; Mice, Inbred C57BL; Random Allocation; Rats; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; Thioacetamide

The liver disease is one of the most important traditional public health problems in Egypt. Oxidative stress is attributed to such pathological condition that further contributes to the initiation and progression of liver injury. In the present study, we have investigated if the strong antioxidant power of Nicotinamide (NA), Vitamin B2 (VB2), and Vitamin C (VC) can ameliorate TAA-induced oxidative stress-mediated liver injury in the rats.. Thirty-six albino rats were divided into six groups: Control group; TAA group (IP injection with TAA at a dosage of 200 mg/Kg three times a week for two months); TAA + NA group (rats administered with NA at a dosage of 200 mg/kg daily besides TAA as in the control); TAA + VB2 group (rats administered with vitamin B2 at a dosage of 30 mg/kg daily besides injection with TAA); TAA + VC group (rats administered with vitamin C at a dosage of 200 mg/kg daily along with injection of TAA). TAA + NA + VB + VC group (rats administered the with the three vitamins daily in TAA pre-injected at the respective doses described above).. Treatment of rats with TAA led to a significant elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total bilirubin, cholesterol, triglycerides, low-density lipoprotein (LDL) and tumor necrosis factor-alpha (TNF-α) in the serum samples. Moreover, malondialdehyde (MDA), hydroxyproline and nitic oxide (NO) were also significantly increased in the TAA-treated rats, while reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were significantly compromised in the hepatic samples. Rats administered with NA, VB2, and VC as individually or in combination ameliorated the deleterious effects of TAA that was confirmed by histopathology. However, the combination of the three vitamins was found more effective as compared to each of the vitamins.. Our work demonstrates that NA, VB2, and VC cross-talk with each other that act as a more potent biochemical chain of antioxidant defense against TAA-induced toxicities in vivo.

Topics: Animals; Antioxidants; Ascorbic Acid; Chemical and Drug Induced Liver Injury; Drug Combinations; Humans; Liver; Niacinamide; Oxidative Stress; Rats; Riboflavin; Thioacetamide

Nutmeg is a Traditional Chinese Medicine used to treat gastrointestinal diseases. Some reports have indicated that nutmeg has hepatoprotective activity. In this study, a thioacetamide (TAA)-induced acute liver injury model in mice was used to explore the mechanism of the protective effects of nutmeg extract (NME), including its major bioactive component myrislignan. The results indicated that NME could effectively protect TAA-induced liver damage as assessed by recovery of increased serumtransaminases, decrease in hepatic oxidative stress, and lower hepatic inflammation. Metabolomics analysis further revealed that treatment with NME led to the recovery of a series of lipids including lysophosphatidylcholines that were decreased and a lowering of acylcarnitines that were increased in mouse plasma and liver after TAA exposure. Gene expression analysis demonstrated that the hepatoprotective effect of NME was achieved by modulation of the peroxisome proliferator-activated receptor alpha (PPARα) as well as the decrease in oxidative stress. NME could not protect from TAA-induced liver injury in Ppara-null mice, suggesting that its protective effect was dependent on PPARα. Myrislignan, a representative neolignan in nutmeg, showed potent protective activity against TAA-induced liver toxicity. These data demonstrate that nutmeg alleviates TAA-induced liver injury through the modulation of PPARα and that the lignan compounds in nutmeg such as myrislignan partly contributed to this action.

Topics: Animals; Carnitine; Chemical and Drug Induced Liver Injury; Lipids; Metabolomics; Mice; Mice, Knockout; Myristica; Oxidative Stress; PPAR alpha; Protective Agents; Thioacetamide

Aldehyde reductase (Akr1a) has been reported to be involved in detoxification of reactive aldehydes as well as in the synthesis of bioactive compounds such as ascorbic acid (AsA). Because Akr1a is expressed at high levels in the liver and is involved in xenobiotic metabolism, our objective was to investigate the hepato-protective role of Akr1a in a thioacetamide (TAA)-induced hepatotoxicity model using Akr1a-deficient (Akr1a

Topics: Activation, Metabolic; Aldehyde Reductase; Animals; Apoptosis; Biomarkers; Carcinogens; Chemical and Drug Induced Liver Injury; Crosses, Genetic; Cytochrome P-450 CYP2E1; Drug Resistance; Endoplasmic Reticulum Stress; Liver; Male; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Oxidative Stress; Thioacetamide; Toxicokinetics

Impaired motor function, due to the dysfunction of the basal ganglia, is the most common syndrome of hepatic encephalopathy (HE), and its etiology remains poorly understood. Neural oxidative stress is shown to be the major cellular defects contributing to HE pathogenesis. Mitochondrial uncoupling protein 2 (UCP2) has been implicated in neuroprotection in several neurological disorders. We explored the neuroprotective role of UCP2 within the substantia nigra pars reticulate (SNr), the output structure of the basal ganglia, in HE. The toxin thioacetamide (TAA) induced HE mice showed hypolocomotion, which was associated with decreased ATP levels and loss of antioxidant substances SOD and GSH within the SNr. Stable overexpression of UCP2 via AAV-UCP2 under the control of the UCP2 promoter in bilateral SNr preserved local ATP level, increased antioxidant substances, and ameliorated locomotion defects after severe liver failure. Contrary to UCP2 overexpression, targeted knockdown of UCP2 within bilateral SNr via AAV-UCP2 shRNA exacerbated the impaired mitochondrial dysfunction and hypokinesia in HE mice. The modulatory effects of UCP2 was due to mediation of K

Topics: Animals; Basal Ganglia; Behavior, Animal; Chemical and Drug Induced Liver Injury; Dependovirus; Disease Models, Animal; Dyskinesias; Locomotion; Male; Mice; Mice, Inbred C57BL; Mitochondria; Thioacetamide; Uncoupling Protein 2

The urgent unmet need for hepatocellular carcinoma (HCC) therapies is addressed here by characterising a novel mouse model of HCC in the context of ongoing liver damage and overnutrition. Male C57Bl/6J mice were treated with diethylnitrosamine (DEN) and thioacetamide (TAA), and some were provided with an atherogenic high fat diet (HFD). Inflammation, steatosis, fibrosis, 87 genes, liver lesions and intratumoural leukocyte subsets were quantified up to 24 weeks of age. Adding HFD to DEN/TAA increased fibrosis, steatosis and inflammation, and the incidence of both HCC and non-HCC dysplastic lesions. All lesions contained α-SMA positive fibroblasts. Macrophage marker F4/80 was not significantly different between treatment groups, but the macrophage-associated genes Arg-1 and Cd47 were differentially expressed. Fibrosis, cancer and cell death associated genes were upregulated in DEN/TAA/HFD livers. Fewer Kupffer cells and plasmacytoid dendritic cells were in tumours compared to control liver. In conclusion, combining a hepatotoxin with an atherogenic diet produced more intrahepatic tumours, dysplastic lesions and fibrosis compared to hepatotoxin alone. This new HCC model provides a relatively rapid means of examining primary HCC and potential therapies in the context of multiple hepatotoxins including those derived from overnutrition.

Topics: Alkylating Agents; Animals; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; Diet, High-Fat; Diethylnitrosamine; Gene Expression Regulation, Neoplastic; Liver Neoplasms, Experimental; Male; Mice; Mice, Inbred C57BL; Thioacetamide

Topics: Administration, Oral; Animals; Chemical and Drug Induced Liver Injury; Cytokines; Disease Models, Animal; Humans; Immunity, Innate; Inflammation Mediators; Keratin-18; Liver; Male; Mice; Myeloid Differentiation Factor 88; Plant Extracts; Recovery of Function; Signal Transduction; Thioacetamide; Toll-Like Receptor 4; Toll-Like Receptor 9; Zygophyllaceae

Topics: Animals; Chemical and Drug Induced Liver Injury; DNA Damage; Glyburide; Hepatic Stellate Cells; Hypoglycemic Agents; Liver; Male; Matrix Metalloproteinase 2; NLR Family, Pyrin Domain-Containing 3 Protein; Protective Agents; Rats, Wistar; Thioacetamide

Liver cirrhosis is associated with a wide range of cardiovascular abnormalities including hyperdynamic circulation and cirrhotic cardiomyopathy. The pathogenic mechanisms of these cardiovascular changes are multifactorial and include vascular dysregulations.. The present study tested the hypothesis that the systemic vascular hyporesponsiveness in thioacetamide (TAA)-induced liver injury model is dependent on nitric oxide (NO) and cyclooxygenase (COX) derivatives.. Wistar rats were treated with TAA for eight weeks to induce liver injury.. The maximal contractile response in concentration-effect curves to phenylephrine was decreased in aorta from TAA-treated rats, but no differences were found in aorta without endothelium, suggesting an endothelium-dependent mechanism in decreased contractile response. There was no difference in the contractile response with and without L-NAME (N(ω)-nitro-l-arginine methyl ester) in rats with liver injury, showing that the TAA treatment impairs NO synthesis. Pre-incubation of the aorta with indomethacin, a COX-inhibitor, normalized the reduced contractile response to phenylephrine in arteries from TAA group. Also, COX-2 and iNOS (inducible nitric oxide syntase) protein expression was increased in aorta from TAA group compared to control group. Animals submitted to TAA treatment had a reduction in systolic blood pressure. Our findings demonstrated that liver injury induced by TAA caused a decrease in aortic contractile response by a COX-dependent mechanism but not by NO release. Also, it was demonstrated an inflammatory process in the aorta of TAA-treated rats by increased expression of COX-2 and iNOS.. Therefore, there is an essential contribution of COX-2 activation in extra-hepatic vascular dysfunction and inflammation present in cirrhosis induced by TAA.

Topics: Animals; Aorta, Thoracic; Blood Pressure; Chemical and Drug Induced Liver Injury; Cyclooxygenase 2; Endothelium, Vascular; Male; Nitric Oxide; Rats; Rats, Wistar; Thioacetamide; Vascular Diseases

Topics: Ammonia; Animals; Aquaporin 4; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Emodin; Ependymoglial Cells; Hepatic Encephalopathy; Liver; Male; Potassium Channels, Inwardly Rectifying; Rats, Sprague-Dawley; Retina; Retinal Degeneration; Thioacetamide

Nicotine exerts a number of physiological effects. The purpose of this study was to determine the effects of nicotine on thioacetamide (TAA)-induced liver fibrosis in mice.. For in vivo experiments, hepatic fibrosis was induced by TAA (0.25 g/kg, i.p.) three times a week for 6 weeks. Mice of TAA treated groups were administered daily with distilled water and nicotine (50 or 100 μg/mL) via gastrogavage throughout the experimental period. For in vitro experiments, HepG2 (human liver cancer cell line) and LX-2 (human hepatic stellate cell line) were used to determine oxidative stress and fibrosis, respectively.. Compared to control groups, TAA treated groups had significantly differences in serum alanine transferase and aspartate aminotransferase levels and nicotine accentuated liver injury. Moreover, nicotine increased the mRNA levels of TAA-induced transforming growth factor-β (TGF-β) and collagen type I alpha 1 in the liver. Nicotine also increased TAA-induced oxidative stress. Histological examination confirmed that nicotine aggravated the degree of fibrosis caused by TAA treatment. Additionally, nicotine enhanced hepatic stellate cell activation via promoting the expression of α-smooth muscle actin.. Oral administration of nicotine significantly aggravated TAA-induced hepatic fibrosis in mice through enhancing TGF-β secretion and TAA-induced oxidative stress. The increase in TGF-β levels might be associated with the strengthening of oxidative processes, subsequently leading to increased hepatic stellate cell activation and extracellular matrix deposition. These results suggest that patients with liver disease should be advised to abandon smoking since nicotine may exacerbate hepatic fibrosis.

Topics: Animals; Biomarkers; Cell Line; Chemical and Drug Induced Liver Injury; Collagen Type I, alpha 1 Chain; Dose-Response Relationship, Drug; Drug Synergism; Fungicides, Industrial; Gene Expression Regulation; Hep G2 Cells; Hepatic Stellate Cells; Hepatocytes; Humans; Liver; Liver Cirrhosis; Male; Mice, Inbred C57BL; Nicotine; Oxidative Stress; Random Allocation; Thioacetamide

The liver is the primary organ participating in the metabolism of xenobiotics and is therefore an important target in the safety assessment of drugs, chemicals and environmental toxins. Drug-induced liver injury (DILI) has recently become widely recognized in human medicine as an adverse event. The progression of DILI often involves "damage-associated molecular patterns" (DAMPs) of gene and protein expression such as high-mobility group boxes (HMGBs), S100 proteins and heat shock proteins (Hsp). DAMPs are released from injured or necrotic cells and are bound to Toll-like receptors (TLRs) and modulate inflammatory reactions. Previously, in thioacetamide (TAA; 300mg/kg body weight, single injection)-induced rat liver, we demonstrated that the expressions of DAMPs, TLR4 and major histocompatibility complex (MHC) class II were simultaneously increased, accompanied with progression of hepatocellular injury and inflammation. Here we investigated the association of DILI and DAMPs, TLRs and MHC class II by using rat livers repeated injections with TAA (100mg/kg body weight, once, three times). Two days after TAA single injection, centrilobular hepatocellular necrosis with infiltration of mononuclear cells was observed, being paralleled with increase in serum levels of aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP). However, two days after duplicate and triplicate injections, only mild degenerative change of hepatocytes and slight infiltration of mononuclear cells were seen in the affected centrilobular area. Serum levels of AST, ALT and ALP were also decreased to the same levels of control. mRNA expressions of DAMPs (HMGBs, S100A4 and Hsp 70-2), TLR4 and MHC class II tended to be increased only on single injection, although the number of MHC class II-positive cells in the centrilobular area was still increased on each examination point. The analysis of enzymes (CYP2E1 and Flavin monooxygenase (FMO) 3), which metabolize TAA in hepatocytes, showed a significant decrease in FMO3 on the duplicate and triplicate injections. Autophagy and regulatory T cells were not significantly changed for the attenuation of hepatocyte injury. Collectively, these results suggest that hepatocytes may adapt accumulation of the toxicant by changing their enzyme functions; furthermore, MHC class II cells, which still showed increased number in the duplicate and triplicate injections, may be related with protection from the toxicant.

Topics: Animals; Chemical and Drug Induced Liver Injury; Down-Regulation; Gene Expression Regulation; Histocompatibility Antigens Class II; HSP70 Heat-Shock Proteins; Injections, Intraperitoneal; Male; Rats, Inbred F344; S100 Calcium-Binding Protein A4; Thioacetamide; Time Factors; Toll-Like Receptors

This study was designed to evaluate the effect of rutin on hepatotoxicity induced by thioacetamide (TAA) in rats. Four groups of male Wistar rats consisting of six rats each were used: Group I: control group; Group II: rats receiving single injection of 300 mg kg

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Apoptosis; Aspartate Aminotransferases; Bilirubin; Chemical and Drug Induced Liver Injury; DNA Fragmentation; Hepatocytes; L-Lactate Dehydrogenase; Liver; Male; Protective Agents; Rats, Wistar; Rutin; Thioacetamide

Lipogenesis is stimulated in the liver by an unfolded protein response (UPR) to endoplasmic reticulum stress under a variety of pathological conditions and results in the accumulation of lipids in hepatocytes. Assuming that UPR is a protective mechanism against stress, we hypothesized that the accumulated lipids might have a beneficial function. We prepared mice with fatty livers by feeding two types of high-calorie diets; a lard-rich high-calorie diet (LHD) or a menhaden oil-containing high-calorie diet (MHD), for two weeks and treated them, as well as control diet (CD)-fed mice, with thioacetamide (TAA), a liver toxicant. When a lethal dose (500mg/kg) of TAA was administered, the LHD-fed mice and the MHD-fed mice survived longer than those fed with CD. The accumulated lipids appeared to be associated with protecting the liver against TAA toxicity (200mg/kg). Consistently, lipid-loaded Hepa 1-6 cells showed a partial resistance to hydrogen peroxide toxicity compared to those cultured in conventional media. In conclusion, while sustained steatosis impairs liver function and leads to hazardous conditions, lipids that transiently accumulate as the result of UPR or other stimuli may exert a beneficial function in the liver at least partly through scavenging reactive oxygen species.

Topics: Animals; Cell Line, Tumor; Chemical and Drug Induced Liver Injury; Diet, High-Fat; Dietary Fats; Disease Models, Animal; Fish Oils; Hepatocytes; Hydrogen Peroxide; Lipid Droplets; Lipid Peroxidation; Lipogenesis; Liver; Male; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Reactive Oxygen Species; Thioacetamide; Time Factors

Thioacetamide (TAA) is a hepatotoxin that rapidly triggers the necrotic process and oxidative stress in the liver. Nevertheless, organic selenium compounds, such as β-selenoamines, can be used as pharmacological agents to diminish the oxidative damage. Thus, the aim of this study was to investigate the protective effect of the antioxidant β-selenoamines on TAA-induced oxidative stress in mice. Here, we observed that a single intraperitoneal injection of TAA (200 mg/kg) dramatically elevated some parameters of oxidative stress, such as lipid peroxidation and reactive oxygen species (ROS) production, as well as depleted cellular antioxidant defenses. In addition, TAA-induced edema and morphological changes in the liver, which correlate with high serum aspartate and alanine aminotransferase enzyme activities, and a decrease in cell viability. Conversely, a significant reduction in liver lipid peroxidation, ROS production, and edema was observed in animals that received an intraperitoneal injection of β-selenoamines (15.6 mg/kg) 1 h after TAA administration.

Topics: Amines; Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Drug Evaluation, Preclinical; Glutathione; Glutathione Peroxidase; Glutathione Transferase; Lipid Peroxidation; Liver; Male; Mice; Organoselenium Compounds; Oxidative Stress; Reactive Oxygen Species; Thioacetamide

To elucidate the role of STAT3 in hepatocarcinogenesis and biliary ductular proliferation following chronic liver injury.. We investigated thioacetamide (TAA)-induced liver injury, compensatory hepatocyte proliferation, and hepatocellular carcinoma (HCC) development in hepatic STAT3-deficient mice. In addition, we evaluated TAA-induced biliary ductular proliferation and analyzed the activation of sex determining region Y-box9 (SOX9) and Yes-associated protein (YAP), which regulate the transdifferentiation of hepatocytes to cholangiocytes.. Both compensatory hepatocyte proliferation and HCC formation were significantly decreased in hepatic STAT3-deficient mice as compared with control mice. STAT3 deficiency resulted in augmentation of hepatic necrosis and fibrosis. On the other hand, biliary ductular proliferation increased in hepatic STAT3-deficient livers as compared with control livers. SOX9 and YAP were upregulated in hepatic STAT3-deficient hepatocytes.. STAT3 may regulate hepatocyte proliferation as well as transdifferentiation into cholangiocytes and serve as a therapeutic target for HCC inhibition and biliary regeneration.

Topics: Adaptor Proteins, Signal Transducing; Animals; Biliary Tract; Carcinogenesis; Carcinoma, Hepatocellular; Cell Cycle Proteins; Cell Proliferation; Cell Transdifferentiation; Chemical and Drug Induced Liver Injury; Hepatocytes; Liver; Liver Neoplasms; Liver Neoplasms, Experimental; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Phosphoproteins; Phosphorylation; Regeneration; SOX9 Transcription Factor; STAT3 Transcription Factor; Thioacetamide; Up-Regulation; YAP-Signaling Proteins

To studied iron metabolism in liver, spleen, and serum after acute liver-damage, in relation to surrogate markers for liver-damage and repair.. Rats received intraperitoneal injection of the hepatotoxin thioacetamide (TAA), and were sacrificed regularly between 1 and 96 h thereafter. Serum levels of transaminases and iron were measured using conventional laboratory assays. Liver tissue was used for conventional histology, immunohistology, and iron staining. The expression of acute-phase cytokines, ferritin light chain (FTL), and ferritin heavy chain (FTH) was investigated in the liver by qRT-PCR. Western blotting was used to investigate FTL and FTH in liver tissue and serum. Liver and spleen tissue was also used to determine iron concentrations.. After a short initial decrease, iron serum concentrations increased in parallel with serum transaminase (aspartate aminotransferase and alanine aminotransferase) levels, which reached a maximum at 48 h, and decreased thereafter. Similarly, after 48 h a significant increase in FTL, and after 72h in FTH was detected in serum. While earliest morphological signs of inflammation in liver were visible after 6 h, increased expression of the two acute-phase cytokines IFN-γ (1h) and IL-1β (3h) was detectable earlier, with maximum values after 12-24 h. Iron concentrations in liver tissue increased steadily between 1 h and 48 h, and remained high at 96 h. In contrast, spleen iron concentrations remained unchanged until 48 h, and increased mildly thereafter (96 h). Although tissue iron staining was negative, hepatic FTL and FTH protein levels were strongly elevated. Our results reveal effects on hepatic iron concentrations after direct liver injury by TAA. The increase of liver iron concentrations may be due to the uptake of a significant proportion of the metal by healthy hepatocytes, and only to a minor extent by macrophages, as spleen iron concentrations do not increase in parallel. The temporary increase of iron, FTH and transaminases in serum is obviously due to their release by damaged hepatocytes.. Increased liver iron levels may be the consequence of hepatocyte damage. Iron released into serum by damaged hepatocytes is obviously transported back and stored via ferritins.

Topics: Animals; Biological Transport; Biomarkers; Chemical and Drug Induced Liver Injury; Cytokines; Disease Models, Animal; Ferritins; Hepatocytes; Humans; Iron; Liver; Male; Rats; Rats, Sprague-Dawley; Spleen; Thioacetamide; Transaminases

Thioacetamide (TAA) administration is widely used for induction of liver cirrhosis in rats, where reactive oxygen radicals (ROS) and nitric oxide (NO) participate in development of liver damage. Cardiac dysfunction is an important complication of liver cirrhosis, but the role of ROS or NO in cardiac abnormalities during liver cirrhosis is not well understood. This was investigated in animals after TAA-induced liver cirrhosis and temporal changes in oxidative stress, NO and mitochondrial function in the heart evaluated. TAA induced elevation in cardiac levels of nitrate before development of frank liver cirrhosis, without gross histological alterations. This was accompanied by an early induction of P38 MAP kinase, which is influenced by ROS and plays an important signaling role for induction of iNOS. Increased nitrotyrosine, protein oxidation and lipid peroxidation in the heart and cardiac mitochondria, suggestive of oxidative stress, also preceded frank liver cirrhosis. However, compromised cardiac mitochondrial function with a decrease in respiratory control ratio and increased mitochondrial swelling was seen later, when cirrhosis was evident. In conclusion, TAA induces elevations in ROS and NO in the heart in parallel to early liver damage. This leads to later development of functional deficits in cardiac mitochondria after development of liver cirrhosis.

Topics: Animals; Chemical and Drug Induced Liver Injury; Female; Heart Diseases; Lipid Peroxidation; Liver; Liver Cirrhosis; Male; Mitochondria, Heart; Mitochondrial Swelling; Myocytes, Cardiac; Nitrates; Nitric Oxide; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Rats, Wistar; Reactive Oxygen Species; Signal Transduction; Thioacetamide; Time Factors; Tyrosine

The present study identified genes showing promoter region hypermethylation by CpG island microarrays in the liver of rats treated with hepatocarcinogen thioacetamide (TAA) for 28days. Among 47 hypermethylated genes, Hist1h2aa, Tmem70, Ube2e2, and Slk were confirmed to show hypermethylation by methylation-specific quantitative polymerase chain reaction (PCR) and pyrosequencing analyses as well as downregulation of transcript levels by real-time reverse transcription-PCR analysis in the livers of rats treated with TAA. All gene products of the 4 selected genes showed decreased immunoreactivity forming negative liver cell foci in a subpopulation of glutathione S-transferase placental form (GST-P)

Topics: Adenoma, Liver Cell; Animals; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; Down-Regulation; Epigenesis, Genetic; Gene Expression Regulation, Neoplastic; Liver; Liver Neoplasms; Membrane Proteins; Rats; Thioacetamide; Ubiquitin-Protein Ligases

Interleukin-17A has been identified as a driver of hepatic stellate cell activation and plays a critical role in the pathogenesis of hepatic fibrosis. However, the underlining fibrosis-promoting mechanism of IL-17A is far from understood. Here we aimed to define whether hepatocytes directly respond to IL-17A stimulation and are associated with the development of hepatic fibrosis. The functional significance of IL-17A was evaluated in bile duct ligation (BDL) or thioacetamide (TAA) injection-induced mouse models of hepatic fibrosis. Human cirrhosis and control tissues were obtained from the patients with cirrhosis who received an open surgical repair process. Neutralizing IL-17A promoted the resolution of BDL or TAA-induced acute or chronic inflammation and fibrosis, resulted in a shift of the suppressive immune response in fibrotic liver toward a Th1-type immune response, and restored autophagy activity in both cholestatic and hepatotoxic liver injury induced fibrotic liver tissues, which was accompanied by a significant inhibition of STAT3 phosphorylation. Moreover, we found that IL-17A stimulated the concentration-and time-dependent phosphorylation of STAT3 in AML-12 liver cells. Blocking STAT3 with a specific inhibitor STATTIC or STAT3 siRNA protected from the IL-17A-induced autophagy suppression in AML-12 cells, indicating that STAT3 mediates IL-17A-suppressed autophagy. Administration of IL-10, which activated STAT3 and inhibited autophagy, reversed the therapeutic effect of IL-17A antagonism in vivo. Our study suggests that the IL-17A/STAT3 signaling pathway plays a crucial role in the pathogenesis of hepatic fibrosis through suppressing hepatocellular autophagy and that blocking this pathway may provide therapeutic benefits for the treatment of hepatic fibrosis.

Topics: Animals; Antibodies, Neutralizing; Autophagy; Cell Line; Chemical and Drug Induced Liver Injury; Cholestasis; Cyclic S-Oxides; Hepatocytes; Humans; Interleukin-10; Interleukin-17; Liver; Liver Cirrhosis, Experimental; Male; Mice, Inbred BALB C; Phosphorylation; RNA Interference; Signal Transduction; STAT3 Transcription Factor; Th1 Cells; Thioacetamide; Transfection

Hepatocellular and cholestatic forms of drug-induced liver injury (DILI) are major reasons for late-stage termination of small-molecule drug discovery research projects. Biochemical serum markers are limited in their ability to sensitively and specifically detect both of these common DILI forms in preclinical models, and tissue-specific approaches to assessing this are labor intensive, requiring extensive animal dosing, tissue preparation, and pathology assessment. In vivo fluorescent imaging offers noninvasive detection of biologic changes detected directly in the livers of living animals. Three different near-infrared fluorescent imaging probes, specific for cell death (Annexin-Vivo 750), matrix metalloproteases (MMPSense 750 FAST), and transferrin receptor (Transferrin-Vivo 750) were used to measure the effects of single bolus intraperitoneal doses of four different chemical agents known to induce liver injury. Hepatocellular injury-inducing agents, thioacetamide and acetaminophen, showed optimal injury detection with probe injection at 18-24 hours, the liver cholestasis-inducing drug rifampicin required early probe injection (2 hours), and chlorpromazine, which induces mixed hepatocellular/cholestatic injury, showed injury with both early and late injection. Different patterns of liver responses were seen among these different imaging probes, and no one probe detected injury by all four compounds. By using a cocktail of these three near-infrared fluorescent imaging probes, all labeled with 750-nm fluorophores, each of the four different DILI agents induced comparable tissue injury within the liver region, as assessed by epifluorescence imaging. A strategy of probe cocktail injection in separate cohorts at 2 hours and at 20-24 hours allowed the effective detection of drugs with either early- or late-onset injury.

Topics: Acetaminophen; Animals; Chemical and Drug Induced Liver Injury; Early Diagnosis; Fluorescent Dyes; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Optical Imaging; Thioacetamide

Liver disease remains a significant global health problem. Increased caffeine consumption has been associated with a lower prevalence of chronic liver disease. This study aimed to investigate the modifying effects of caffeine on liver injury induced by thioacetamide (TAA) administration in male rats and the possible underlying mechanisms. Forty adult male rats were equally classified into four groups: control group, received only tap water; caffeine-treated group, received caffeine (37.5 mg/kg per day); TAA-treated group, received intraperitoneal (i.p.) TAA (200 mg/kg b.w.) twice a week; and caffeine + TAA-treated group, received combined TAA and caffeine in the same previous doses. After eight weeks of treatment, blood samples were collected for biochemical analysis and liver specimens were prepared for histological and immunohistochemical studies and for assessment of oxidative stress. TAA induced liver toxicity with elevated liver enzymes and histological alterations, fatty changes, apoptosis, and fibrosis evidenced by increased immunohistochemical reaction to matrix metalloproteinase-9 (MMP-9) and collagen type IV in hepatocytes. Also, the levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in serum were significantly elevated. Co-treatment with caffeine and TAA restored normal liver structure and function. Caffeine provided an anti-fibrogenic, anti-inflammatory, and antioxidant effect that was associated with recovery of hepatic histological and functional alterations from TAA-induced hepatotoxicity.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Anti-Inflammatory Agents; Antioxidants; Aspartate Aminotransferases; Bilirubin; Biomarkers; Caffeine; Chemical and Drug Induced Liver Injury; Collagen Type IV; Cytokines; Disease Models, Animal; gamma-Glutamyltransferase; Glutathione; Glutathione Peroxidase; Liver; Male; Matrix Metalloproteinase 9; Oxidative Stress; Rats; Thioacetamide

Liver injuries induced by carbon tetrachloride (CCL4) or thioacetamide (TAA) are dependent on cytochrome P450 2E1 (CYP2E1). CYP2A5 can be induced by TAA but not by CCL4. In this study, liver injury including fibrosis induced by CCL4 or TAA were investigated in wild-type (WT) mice and CYP2A5 knockout (cyp2a5 (-/-) ) mice as well as in CYP2E1 knockout (cyp2e1 (-/-) ) mice as a comparison. Acute and subchronic liver injuries including fibrosis were induced by CCL4 and TAA in WT mice but not in cyp2e1 (-/-) mice, confirming the indispensable role of CYP2E1 in CCL4 and TAA hepatotoxicity. WT mice and cyp2a5 (-/-) mice developed comparable acute liver injury induced by a single injection of CCL4 as well as subchronic liver injury including fibrosis induced by 1 month of repeated administration of CCL4, suggesting that CYP2A5 does not affect CCL4-induced liver injury and fibrosis. However, while 200 mg/kg TAA-induced acute liver injury was comparable in WT mice and cyp2a5 (-/-) mice, 75 and 100 mg/kg TAA-induced liver injury were more severe in cyp2a5 (-/-) mice than those found in WT mice. After multiple injections with 200 mg/kg TAA for 1 month, while subchronic liver injury as indicated by serum aminotransferases was comparable in WT mice and cyp2a5 (-/-) mice, liver fibrosis was more severe in cyp2a5 (-/-) mice than that found in WT mice. These results suggest that while both CCL4- and TAA-induced liver injuries and fibrosis are CYP2E1 dependent, under some conditions, CYP2A5 may protect against TAA-induced liver injury and fibrosis, but it does not affect CCL4 hepatotoxicity.

Topics: Alanine Transaminase; Animals; Aryl Hydrocarbon Hydroxylases; Aspartate Aminotransferases; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2E1; Cytochrome P450 Family 2; Disease Models, Animal; Glutathione; Liver; Liver Cirrhosis; Male; Mice, Inbred C57BL; Mice, Knockout; Thioacetamide; Thiobarbituric Acid Reactive Substances

Obesity increases the risk of chronic liver diseases, including viral hepatitis, alcohol-induced liver disease, and non-alcoholic steatohepatitis. In this study, we investigated the effects of obesity in acute hepatic failure using a murine model of thioacetamide (TA)-induced liver injury. Genetically obese ob/ob mice, together with non-obese ob/+ littermates, were subjected to a single intraperitoneal injection of TA, and examined for signs of hepatic injury. ob/ob mice showed a significantly higher survival rate, lower levels of serum alanine aminotransferase and aspartate aminotransferase, and less hepatic necrosis and apoptosis, compared with ob/+ mice. In addition, ob/ob mice exhibited significantly lower levels of malondialdehyde and significantly higher levels of glutathione and antioxidant enzyme activities compared with their ob/+ counterparts. Bioactivation analyses revealed reduced plasma clearance of TA and covalent binding of [(14)C]TA to liver macromolecules in ob/ob mice. Together, these data demonstrate that genetically obese mice are resistant to TA-induced acute liver injury through diminished bioactivation of TA and antioxidant effects.

Topics: Animals; Chemical and Drug Induced Liver Injury; Lethal Dose 50; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Thioacetamide

Adiponectin is an adipocyte-derived circulating protein with beneficial effects on injured livers. Adiponectin-deficient (adipo(-/-)) mice develop enhanced liver fibrosis, suggesting that adiponectin could be a therapeutic target for liver injury. In the present study, we investigated the protective role of ADP355, an adiponectin-based active short peptide, in thioacetamide (TAA)-induced acute injury and chronic liver fibrosis in mice. ADP355 remarkably reduced TAA-induced necroinflammation and liver fibrosis. ADP355 treatment increased liver glycogen, decreased serum alanine transaminase and alkaline phosphatase activity, and promoted body weight gain, hyper-proliferation and hypo-apoptosis. In addition, ADP355 administration suppressed the TAA-induced activation of hepatic stellate cells and macrophages in the liver. These were associated with the inactivation of TGF-β1/SMAD2 signaling and the promotion of AMPK and STAT3 signaling. Sensitivity of adipo(-/-) mice to chronic liver injury was decreased with ADP355. In conclusion, ADP355 could mimic adiponectin's action and may be suitable for the preclinical or clinical therapy of chronic liver injury.

Topics: Adiponectin; Animals; Anti-Inflammatory Agents; Apoptosis; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Disease Progression; Female; Hepatic Stellate Cells; Liver Cirrhosis; Liver Function Tests; Liver Regeneration; Macrophage Activation; Macrophages; Male; Mice; Mice, Knockout; Oligopeptides; Signal Transduction; STAT3 Transcription Factor; Thioacetamide

Hepatic macrophages play crucial roles in hepatotoxicity. We investigated immunophenotypes of macrophages in liver injury induced in rats by thioacetamide (TAA; 300 mg/kg, intraperitoneal) after hepatic macrophage depletion; hepatic macrophages were depleted by liposomal clodronate (CLD; 10 ml/kg, i.v.) one day before TAA injection. Samples were obtained on post-TAA injection days 0, 1, 2, 3, 5, and 7. TAA injection induced coagulation necrosis of hepatocytes on days 1 through 3 and subsequent reparative fibrosis on days 5 and 7 in the centrilobular area, accompanied by increased numbers of M1 macrophages (expressing cluster of differentiation [CD]68 and major histocompatibility complex class II) and M2 macrophages (expressing CD163 and CD204) mainly on days 1 through 3. TAA + CLD treatment markedly decreased the numbers of M1 and M2 macrophages mainly on days 1 through 3; CD163(+) Kupffer cells were most sensitive to CLD depletion. In TAA + CLD-treated rats, interestingly, coagulation necrosis of hepatocytes was prolonged with more increased levels of hepatic enzymes (aspartate transaminase, alanine transaminase, and alkaline phosphatase) to TAA-treated rats; reparative fibrosis was incomplete and replaced by dystrophic calcification in the injured area, indicating the aggravated damage. Furthermore, in TAA + CLD-treated rats, inflammatory factors (monocyte chemoattractant protein [MCP]-1, interferon-γ, tumor necrosis factor-α, and interleukin-10) and fibrosis-related factors (transforming growth factor-β1, matrix metalloproteinase-2, tissue inhibitor of metalloproteinase-1) were decreased at messenger RNA levels, indicating abnormal macrophage functions. It was clearly demonstrated that hepatic macrophages have important roles in tissue damage and remodeling in hepatotoxicity.

Topics: Animals; Chemical and Drug Induced Liver Injury; Hepatocytes; Immunohistochemistry; Liver; Macrophages; Male; Myofibroblasts; Necrosis; Rats; Rats, Inbred F344; Thioacetamide

The chromatin remodeling activity of mammalian SWI/SNF complex is carried out by either Brahma (BRM) or Brahma-related gene (BRG-1). The BRG-1 regulates genes involved in cell proliferation, whereas BRM is associated with cell differentiation, and arrest of cell growth. Global modifications of histones and expression of genes of chromatin-remodeling subunits have not been studied in in vivo model systems. In the present study, we investigate epigenetic modifications of histones and the expression of genes in thioacetamide (TAA)-induced liver injury and regeneration in a mouse model. In the present study, we report that hepatocyte proliferation and H3S10 phosphorylation occur during 60 to 72 h post TAA treatment in mice. Furthermore, there was change in the H3K9 acetylation and H3K9 trimethylation pattern with respect to liver injury and regeneration phase. Looking into the expression pattern of Brg-1 and Brm, it is evident that they contribute substantially to the process of liver regeneration. The SWI/SNF remodeler might contain BRG-1 as its ATPase subunit during injury phase. Whereas, BRM-associated SWI/SNF remodeler might probably be predominant during decline of injury phase and initiation of regeneration phase. Furthermore, during the regeneration phase, BRG-1-containing remodeler again predominates. Considering all these observations, the present study depicts an interplay between chromatin interacting machineries in different phases of thioacetamide-induced liver injury and regeneration.

Topics: Animals; Cell Cycle; Cell Differentiation; Cell Proliferation; Chemical and Drug Induced Liver Injury; Chromatin; Chromatin Assembly and Disassembly; Chromosomal Proteins, Non-Histone; DNA Helicases; Epigenesis, Genetic; Female; Hepatocytes; Histones; Liver; Liver Regeneration; Mice; Nuclear Proteins; Phosphorylation; Signal Transduction; Thioacetamide; Transcription Factors

Drug-induced liver injury (DILI) is a common problem in human medicine and it is a major reason to withdraw marketed drugs. However, the mechanism of DILI is still less known. Damage-associated molecular patterns (DAMPs), such as high-mobility group boxes (HMGBs), S100 proteins and heat shock proteins (HSPs), are released from injured or necrotic cells, bind to toll-like receptors (TLRs) and modulate inflammatory reactions. Here we investigated the kinetics of DAMPs, TLRs and MHC class II in a rat model of DILI with thioacetamide (TAA). After TAA administration, extensive necrosis was observed on days 1 and 2, followed by infiltration of inflammatory cells on day 3. The levels of serum liver enzymes also peaked on day 1. Expression of HMGB-1, -2 and S100A4 peaked on day 2. TLR-4 was up-regulated on day 3. The number of MHC class II-positive macrophages increased until day 2. These results suggest that HMGB-1, -2 and S100A4 are associated with hepatocellular necrosis and that DAMPs may activate TLR-4 and MHC class II during TAA-induced liver injury. Our data would contribute to the elucidation of the mechanism of DILI.

Topics: Alarmins; Animals; Blotting, Western; Chemical and Drug Induced Liver Injury; Hepatocytes; Histocompatibility Antigens Class II; Kinetics; Macrophages; Male; Rats, Inbred F344; Real-Time Polymerase Chain Reaction; Thioacetamide; Toll-Like Receptor 4; Toll-Like Receptors; Up-Regulation

In an attempt to explore the role of the JAK/STAT pathway in liver inflammation, we investigated the effect of intervening this pathway by ruxolitinib in thioacetamide (TAA)-induced hepatotoxicity. Ruxolitinib treatments were administered to male mice either before or after intoxication with TAA. The hepatic histopathological and serum biochemical assessment revealed that ruxolitinib pre-treatments dose-dependently reduced TAA-induced liver injury, caspase 3 cleavage and increase in number of hepatocytes positive for the pro-apoptotic Bax, as well as inflammatory cells positive for F4/80 and myeloperoxidase activity in the liver. Ruxolitinib pre-treatments also curbed TAA-induced rise in NF-κB nuclear expression and STAT3 phosphorylation. Ruxolitinib pre-treatments also lowered TAA-induced elevation of hepatic oxidative stress parameters (total nitrate/nitrite and 4-hydroxynonenal), but did not restore the hepatic antioxidant reduced glutathione. Interestingly, ruxolitinib, especially at a dose of 200 mg/kg, dampened the overproduction of pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ, IL-23 and IL-17A), which coincided with boosting the release of the anti-inflammatory cytokine IL-10. Ruxolitinib when used as a post-treatment (1 and 3 h after TAA-insult) could still spare the liver from injury and might be clinically applicable. In conclusion, the multimechanistic-hepatoprotective activity of ruxolitinib can be linked to its ameliorative properties on cellular death, oxidative stress and inflammation machinery.

Topics: Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Glutathione; Immunoenzyme Techniques; Inflammation; Janus Kinases; Male; Mice; Mice, Inbred BALB C; NF-kappa B; Nitriles; Oxidative Stress; Pyrazoles; Pyrimidines; STAT Transcription Factors; Thioacetamide; Tumor Necrosis Factor-alpha

Compound-induced liver injury leading to fibrosis remains a challenge for the development of an Adverse Outcome Pathway useful for human risk assessment. Latency to detection and lack of early, systematically detectable biomarkers make it difficult to characterize the dynamic and complex intercellular interactions that occur during progressive liver injury. Here, we demonstrate the utility of bioprinted tissue constructs comprising primary hepatocytes, hepatic stellate cells, and endothelial cells to model methotrexate- and thioacetamide-induced liver injury leading to fibrosis. Repeated, low-concentration exposure to these compounds enabled the detection and differentiation of multiple modes of liver injury, including hepatocellular damage, and progressive fibrogenesis characterized by the deposition and accumulation of fibrillar collagens in patterns analogous to those described in clinical samples obtained from patients with fibrotic liver injury. Transient cytokine production and upregulation of fibrosis-associated genes ACTA2 and COL1A1 mimics hallmark features of a classic wound-healing response. A surge in proinflammatory cytokines (eg, IL-8, IL-1β) during the early culture time period is followed by concentration- and treatment-dependent alterations in immunomodulatory and chemotactic cytokines such as IL-13, IL-6, and MCP-1. These combined data provide strong proof-of-concept that 3D bioprinted liver tissues can recapitulate drug-, chemical-, and TGF-β1-induced fibrogenesis at the cellular, molecular, and histological levels and underscore the value of the model for further exploration of compound-specific fibrogenic responses. This novel system will enable a more comprehensive characterization of key attributes unique to fibrogenic agents during the onset and progression of liver injury as well as mechanistic insights, thus improving compound risk assessment.

Topics: Biomarkers; Bioprinting; Cells, Cultured; Chemical and Drug Induced Liver Injury; Coculture Techniques; Collagen; Cytokines; Dose-Response Relationship, Drug; Endothelial Cells; Feasibility Studies; Gene Expression Regulation; Hepatic Stellate Cells; Hepatocytes; Humans; Liver; Liver Cirrhosis; Methotrexate; Phenotype; Printing, Three-Dimensional; Risk Assessment; Thioacetamide; Time Factors

Plumbagin is a quinonoid constituent extracted from Plumbago genus, and it exhibits diverse pharmacological effects. This study thoroughly investigated the effects of plumbagin on thioacetamide-induced acute and chronic liver injury. Results shown that plumbagin increased survival rate, reduced liver congestion and inflammation, and decreased macrophages and neutrophils in the fulminant hepatic failure model, and remarkably diminished liver fibrosis and inflammation in the chronic liver injury model. Furthermore, plumbagin significantly suppress the HSCs/myofibroblasts activation by reduced expression of markers α-SMA and COL-1/3, and reduced macrophage in liver. In the in vitro study, plumbagin induced apoptosis and suppressed the proliferation of LX-2 cells (human HSCs). Plumbagin treatment increased AMPK phosphorylation and attenuated NF-κB, STAT3, and Akt/mTOR signals in LX-2 cells, while SMAD2 phosphorylation was not changed. Noticeably, plumbagin promoted AMPK binding to p300 which is a cofactor of SMAD complex, this may further competitively decreases the p300/SMAD complex initiated transcription of COL-1/3 and α-SMA. Additionally, plumbagin hampered inflammation related NF-κB signal in RAW 264.7 cells. In conclusion, these findings indicate that plumbagin may be a powerful drug candidate to protect the liver from acute and chronic damage by inhibiting inflammation and collagen production.

Topics: AMP-Activated Protein Kinases; Animals; Anti-Inflammatory Agents; Apoptosis; Chemical and Drug Induced Liver Injury; Collagen Type I; Collagen Type III; Cytoprotection; Female; Hepatic Stellate Cells; Humans; Liver; Liver Cirrhosis, Experimental; Liver Failure, Acute; Liver Regeneration; Mice; Mice, Inbred ICR; Myofibroblasts; Naphthoquinones; NF-kappa B; p300-CBP Transcription Factors; Phosphorylation; Proto-Oncogene Proteins c-akt; RAW 264.7 Cells; Signal Transduction; STAT3 Transcription Factor; Thioacetamide; TOR Serine-Threonine Kinases

Collagen produced during the process of liver fibrosis can induce a hepatocellular protective response through ERK1 signalling. However, the influence of T cells and associated cytokine production on this protection is unknown. In addition, athymic mice are frequently used in hepatocellular carcinoma xenograft experiments but current methods limit our ability to study the impact of liver fibrosis in this setting due to high mortality. Therefore, a mouse model of liver fibrosis lacking T cells was developed using Foxn1 nu/nu mice and progressive oral administration of thioacetamide (TAA) [0.01-0.02%] in drinking water. Fibrosis developed over a period of 16 weeks (alpha-SMA positive area: 20.0 ± 2.2%, preCol1a1 mRNA expression: 11.7 ± 4.1 fold changes, hydroxyproline content: 1041.2 ± 77μg/g of liver) at levels comparable to that of BALB/c mice that received intraperitoneal TAA injections [200 μg/g of body weight (bw)] (alpha-SMA positive area: 20.9 ± 2.9%, preCol1a1 mRNA expression: 13.1 ± 2.3 fold changes, hydroxyproline content: 931.6 ± 14.8μg/g of liver). No mortality was observed. Athymic mice showed phosphorylation of ERK1/2 during fibrogenesis (control 0.03 ± 0.01 vs 16 weeks 0.22 ± 0.06AU; P<0.05). The fibrosis-induced hepatoprotection against cytotoxic agents, as assessed histologically and by serum AST levels, was not affected by the absence of circulating T cells (anti-Fas JO2 [0.5μg/g bw] for 6h (fibrotic 4665 ± 2596 vs non-fibrotic 13953 ± 2260 U/L; P<0.05), APAP [750 mg/kg bw] for 6 hours (fibrotic 292 ± 66 U/L vs non-fibrotic 4086 ± 2205; P<0.01) and CCl4 [0.5mL/Kg bw] for 24h (fibrotic 888 ± 268 vs non-fibrotic 15673 ± 2782 U/L; P<0.001)). In conclusion, liver fibrosis can be induced in athymic Foxn1 nu/nu mice without early mortality. Liver fibrosis leads to ERK1/2 phosphorylation. Finally, circulating T lymphocytes and associated cytokines are not involved in the hepatocellular protection afforded by liver fibrosis.

Topics: Animals; Blotting, Western; Carcinogens; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Fluorescent Antibody Technique; Liver; Liver Cirrhosis; Male; Mice; Mice, Inbred BALB C; Mice, Nude; T-Lymphocytes; Thioacetamide; Transcriptome

An increase in hepatic iron concentration might exacerbate liver injury. However, it is unknown whether hepatic iron overload may exacerbate acute liver injury from various toxins. Therefore, we evaluated how manipulations to increase hepatic iron concentration affected the extent of acute liver injury from thioacetamide. In this study, we used rats with either "normal" or increased hepatic iron concentration. Iron overload was induced by either providing excess iron in the diet or by injecting iron subcutaneously. Both routes of providing excess iron induced an increase in hepatic iron overload. Meanwhile, the subcutaneous route induced both hepatocellular and sinusoidal cell iron deposition; the oral route induced lesser degree of hepatic iron concentration and only hepatocellular iron overload. Thioacetamide administration to the rats with "normal" hepatic iron concentration induced hepatic cell necrosis and apoptosis associated with a remarkable increase in serum aminotransaminases and depletion of hepatic glutathione and other antioxidative indices. Thioacetamide administration to the iron-overloaded rats exacerbated the extent of liver injury only in the rats orally induced with iron overload. In the rats subcutaneously induced with iron overload, the extent of liver injury from thioacetamide was not different from that observed in the rats with "normal" iron overload. It was concluded that the outcome of thioacetamide-induced acute liver injury may depend on both the level of hepatic iron concentration and on the cellular distribution of iron. While isolated hepatocellular iron overload may exacerbate thioacetamide-induced acute liver injury, a combined hepatocellular and sinusoidal cell iron deposition, even at high hepatic iron concentration, had no such an effect.

Topics: Acute Disease; Animals; Chemical and Drug Induced Liver Injury; Iron Overload; Liver; Male; Rats; Rats, Sprague-Dawley; Thioacetamide

The aim of this study was to investigate the effect of epigallocatechin gallate (EGCG) on uncoupling protein 2 regulation in an acute liver injury-animal model.. Twenty seven male Wistar rats were divided into three groups: control group (n = 9), TAA group (n = 9): acute liver injury was induced by the intraperitoneal injection of thioacetamide (200 mg/kg) and EGCG/TAA (n = 9 rats): Epigallocatechin gallate was given two weeks prior to the induction of acute liver injury by thioacetamide. The levels of uncoupling protein 2, CRP, TNF-α and interleukins (IL) 6 and 18 were analyzed in the liver using PCR analysis.. Q-PCR analysis showed that the genetic expression of UCP2, TNF-α and CRP in the EGCG/TAA group was the least in comparison to other groups (P ≤ 0.005). The IL-6 and IL-18 were upregulated after induction of acute liver injury, but this upregulation was significantly less in the group that received epigallocatechin gallate (EGCG/TAA) compared to the TAA group. In addition, histological examination showed a reduction in hepatocyte injury in EGCG/TAA compared to the TAA group.. Epigallocatechin gallate administration prior to induction of acute liver injury down-regulates uncoupling protein 2 expression and reduces IL-6, IL-18, TNF-α and CRP.

Topics: Animals; Antioxidants; Catechin; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Ion Channels; Male; Mitochondrial Proteins; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; Thioacetamide; Uncoupling Protein 2

Recent studies have shown that increased expression of liver hypoxia inducible factor 2-α (HIF-2α) leads to liver inflammation and a pro-fibrotic gene expression signature. Aryl hydrocarbon Receptor Nuclear Translocator (ARNT) is required for HIF-2α transcriptional activity and has previously been shown to regulate hepatic metabolism in mice. In these studies we examined the role of hepatocyte ARNT in the thioacetamide (TAA)-induced model of liver fibrosis.. Hepatocyte-specific ARNT-null (LARNT) mice were created using an albumin promoter-driven Cre recombinase. LARNT and floxed control (FC) littermates were placed on chow diet and received twice weekly intraperitoneal injections of 0.15mg/g body weight of TAA for 13 weeks.. TAA treated LARNT and FC mice had a similar pattern of fibrosis. Quantification of Sirius red histology staining and hydroxyproline content revealed mixed results in terms of collagen deposition in LARNT livers. There was no significant difference in hepatocyte apoptosis or proliferation, as assessed by cleaved Caspase-3 and Ki67 respectively. LARNT mice had decreased macrophage accumulation, and decreased liver mRNA expression of Col1A1, Col1A2, Col5A1, Tgfβ1, Tgfβ2, Timp1 and Timp2.. Deletion of hepatocyte ARNT leads to altered expression of collagen associated mRNA and reduced macrophage infiltration in the TAA-induced model of liver fibrosis. It appears that hepatocyte ARNT is not a requirement for initiation of liver fibrogenesis, but does regulate pro-fibrotic gene expression and macrophage accumulation.

Topics: Animals; Apoptosis; Aryl Hydrocarbon Receptor Nuclear Translocator; Cell Proliferation; Chemical and Drug Induced Liver Injury; Collagen; Cytokines; Disease Models, Animal; Gene Deletion; Gene Expression Regulation; Hepatocytes; Liver Cirrhosis; Macrophages; Male; Mice; Mice, Knockout; RNA, Messenger; Thioacetamide

A liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS)-based metabolomics approach was employed to identify endogenous metabolites as potential biomarkers for thioacetamide (TAA)-induced liver injury. TAA (10 and 30mg/kg), a well-known hepatotoxic agent, was administered daily to male Sprague-Dawley (SD) rats for 28days. We then conducted untargeted analyses of endogenous serum and liver metabolites. Partial least squares discriminant analysis (PLS-DA) was performed on serum and liver samples to evaluate metabolites associated with TAA-induced perturbation. TAA administration resulted in altered levels of bile acids, acyl carnitines, and phospholipids in serum and in the liver. We subsequently demonstrated and confirmed the occurrence of compromised bile acid homeostasis. TAA treatment significantly increased serum levels of conjugated bile acids in a dose-dependent manner, which correlated well with toxicity. However, hepatic levels of these metabolites were not substantially changed. Gene expression profiling showed that the hepatic mRNA levels of Ntcp, Bsep, and Oatp1b2 were significantly suppressed, whereas those of basolateral Mrp3 and Mrp4 were increased. Decreased levels of Ntcp, Oatp1b2, and Ostα proteins in the liver were confirmed by western blot analysis. These results suggest that serum bile acids might be increased due to the inhibition of bile acid enterohepatic circulation rather than increased endogenous bile acid synthesis. Moreover, serum bile acids are a good indicator of TAA-induced hepatotoxicity.

Topics: Animals; Bile Acids and Salts; Biomarkers; Chemical and Drug Induced Liver Injury; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Enterohepatic Circulation; Gene Expression Profiling; Liver; Male; Membrane Transport Proteins; Metabolomics; Rats, Sprague-Dawley; RNA, Messenger; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Thioacetamide; Time Factors; Up-Regulation

Pentoxifylline (PTX) is a non-selective phosphodiesterase inhibitor with the effects of antioxidation, anti-inflammation and anti-fibrosis that has been shown to induce damage in liver. The purpose of this study is to investigate the effects and possible mechanisms of PTX on thioacetamide (TAA)-induced acute liver injury in rats. Male Sprague-Dawley (SD) rats were divided into four groups: control, PTX, TAA and PTX+TAA treated groups. Rats were administrated TAA together with or without PTX for a week and sacrificed 24 h after the last intragastric administration of PTX. Histopathological analysis was carried out. The liver function, the indices of oxidative stress including malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) in liver tissues, and pro-inflammatory cytokines expressions were examined. The mRNA level of NF-κB p65 in liver was also determined. PTX significantly attenuated TAA-induced liver injury. The serum transaminase and MDA levels were reduced while the levels of SOD and GSH were increased, as compared with the TAA-treated group. PTX also remarkably suppressed the secretions of pro-inflammatory cytokines and the nuclear factor-κB (NF-κB) activation induced by TAA. In addition, the histopathological analysis showed that the range and degree of liver tissue lesions were improved obviously in PTX treated group. Pentoxifylline could ameliorate the effects of thioacetamide-induced acute liver injury in rats by inhibiting oxidative stress, expressions of pro-inflammatory cytokines and NF-κB activation.

Topics: Animals; Chemical and Drug Induced Liver Injury; Cytokines; Glutathione; Liver; Male; Malondialdehyde; NF-kappa B; Oxidative Stress; Pentoxifylline; Protective Agents; Rats; Rats, Sprague-Dawley; Superoxide Dismutase; Thioacetamide

In vertebrates, canonical Hedgehog (Hh) pathway activation requires Smoothened (SMO) translocation to the primary cilium (Pc), followed by a GLI-mediated transcriptional response. In addition, a similar gene regulation occurs in response to growth factors/cytokines, although independently of SMO signalling. The Hh pathway plays a critical role in liver fibrosis/regeneration, however, the mechanism of activation in chronic liver injury is poorly understood. This study aimed to characterise Hh pathway activation upon thioacetamide (TAA)-induced chronic liver injury in vivo by defining Hh-responsive cells, namely cells harbouring Pc and Pc-localised SMO.. C57BL/6 mice (wild-type or Ptc1(+/-)) were TAA-treated. Liver injury and Hh ligand/pathway mRNA and protein expression were assessed in vivo. SMO/GLI manipulation and SMO-dependent/independent activation of GLI-mediated transcriptional response in Pc-positive (Pc(+)) cells were studied in vitro.. In vivo, Hh activation was progressively induced following TAA. At the epithelial-mesenchymal interface, injured hepatocytes produced Hh ligands. Progenitors, myofibroblasts, leukocytes and hepatocytes were GLI2(+). Pc(+) cells increased following TAA, but only EpCAM(+)/GLI2(+) progenitors were Pc(+)/SMO(+). In vitro, SMO knockdown/hGli3-R overexpression reduced proliferation/viability in Pc(+) progenitors, whilst increased proliferation occurred with hGli1 overexpression. HGF induced GLI transcriptional activity independently of Pc/SMO. Ptc1(+/-) mice exhibited increased progenitor, myofibroblast and fibrosis responses.. In chronic liver injury, Pc(+) progenitors receive Hh ligand signals and process it through Pc/SMO-dependent activation of GLI-mediated transcriptional response. Pc/SMO-independent GLI activation likely occurs in Pc(-)/GLI2(+) cells. Increased fibrosis in Hh gain-of-function mice likely occurs by primary progenitor expansion/proliferation and secondary fibrotic myofibroblast expansion, in close contact with progenitors.

Topics: Animals; Chemical and Drug Induced Liver Injury; Chronic Disease; Cilia; Epithelial-Mesenchymal Transition; Hedgehog Proteins; Kruppel-Like Transcription Factors; Liver; Male; Mice; Mice, Inbred C57BL; Nuclear Proteins; Receptors, G-Protein-Coupled; Signal Transduction; Smoothened Receptor; Thioacetamide; Zinc Finger Protein GLI1; Zinc Finger Protein Gli2

"Classically activated macrophages (M1)" and "alternatively activated macrophages (M2)", which appear in injured tissues, control either inflammation or remodeling. The mechanism remains unclear. To clarify the M1-/M2-macrophage polarization in acute liver injury, M1- and M2-related factors were analysed in F344 rats by a single injection of TAA (300 mg/kg BW), and liver samples were collected on post injection (PI) hour 10 and days 1 to 10. Macrophage immunophenotypes were analyzed by single and double immunolabeling. M1-/M2-related factors were analyzed by real-time RT-PCR. On PI hour 10 (when centrilobular lesions were not still developed), expressions of IFN-γ, TNF-α, IL-1β, and IL-6 for M1, and IL-4 for M2 were already increased, followed by increased expressions of IL-10 and TGF-β1 for M2 on PI days 1-3 with development of centrilobular lesions and subsequent reparative fibrosis. On PI hour 10, CD204⁺ and MHC class II⁺ macrophages already increased in the intact periportal/Glisson's sheath regions, accompanied by an increased number of granzyme B⁺ NK cells. Reactive cells at PI hour 10 might produce M1-related factors. In addition to these macrophages, CD68⁺ and CD163⁺ macrophages, and CD3⁺ T cells appeared in the injured centrilobular region on PI days 1-3; there were macrophages reacting simultaneously to CD68/MHC class II, CD163/MHC class II, CD68/CD204, CD163/CD204, and MHC class II/CD204 in varying degrees. Although CD68⁺ and CD163⁺ macrophages are regarded as M1- and M2-types, respectively, the double labeling indicated that macrophage immunophenotypes are interchangeable in injured regions and subsequent fibrosis. An M1-/M2-macrophage paradigm would be useful to analyze hepatotoxicity and to understand the pathogenesis.

Topics: Animals; Chemical and Drug Induced Liver Injury; Fluorescent Antibody Technique; Immunophenotyping; Inflammation; Macrophages; Male; Rats, Inbred F344; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Thioacetamide

Single-dose thioacetamide (TAA) administration induces inflammation and acute liver damage. The mechanism of inflammatory cell recruitment in the liver is still unclear. The aim of this study was to examine the sequence and recruitment of inflammatory cells in different liver regions in relation to CXC- and CC-chemokine and cytokine expression during acute liver injury. Single-dose TAA was administered to rats intraperitoneally, and animals were killed at different time points thereafter. Serum and liver tissue were taken and frozen immediately. Tissue was used for immunostaining cryostat sections, RNA, and protein extraction. RT-PCR and western blotting were performed for RNA and protein analysis, respectively. An early increase (3 h) in CXCL8/IL-8 levels was measured followed by a marked release in MCP1/CCL2 (24 h) serum levels after TAA administration compared with controls. Similarly, an early increase in specific RNA of hepatic chemokines CXCL1/KC and CXCL8/IL-8 was found at 3 h, followed by an upregulation of CXCL5/LIX (6 h), CXCL2/MIP-2 (12 h), and MCP1/CCL2 gene expression at 24-48 h. Further, an induction of pro-inflammatory cytokines IFN-γ and IL-1β followed by IL-6 and TNF-α was observed with a maximum at 12 h. The magnitude of increase in gene expression of TNF-α and MCP1/CCL2 was the highest among all cytokines and chemokines, respectively. By means of immunohistochemistry, an early (12-24 h) increase in the number of only neutrophil granulocytes (NGs) attached to and around portal vessel walls was observed, followed by increased numbers of mononuclear phagocytes (24-48 h) along the sinusoids. Treatment of the human monocytic cell line U-937 with TNF-α increased the gene expression of CXCL1/KC, CXCL8/IL-8, and MCP1/CCL2. Conversely, adding of infliximab (IFX) to the culture medium inhibited this upregulation significantly. In conclusion, single-dose TAA administration induces a sequence of events with a defined upregulation of gene expression of inflammatory chemokines and cytokines and a transient accumulation of NGs within the portal area and macrophages along the sinusoids throughout the liver. Periportal inflammation seems to precede hepatocellular damage.

Topics: Analysis of Variance; Animals; Antibodies, Monoclonal; Blotting, Western; Chemical and Drug Induced Liver Injury; Chemokine CCL2; Chemokines; Cytokines; DNA Primers; Gene Expression Regulation; Immunohistochemistry; Infliximab; Phagocytes; Rats; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Thioacetamide; Time Factors

Systemic iron homeostasis is tightly regulated by the interaction between iron regulatory molecules, mainly produced by the liver. However, the molecular mechanisms of iron regulation in liver diseases remain to be elucidated. Here we analyzed the expression profiles of iron regulatory molecules during transient iron overload in a rat model of thioacetamide (TAA)-induced acute liver injury. After TAA treatment, mild hepatocellular degeneration and extensive necrosis were observed in the centrilobular region at hour 10 and on day 1, respectively. Serum iron increased transiently at hour 10 and on day 1, in contrast to hypoferremia in other rodent models of acute inflammation reported previously. Thereafter, up-regulation of hepcidin, a central regulator of systemic iron homeostasis, was observed in hepatocytes on day 2. Expression of transferrin receptor 1 and ferritin subunits increased to a peak on day 3, followed by increases in liver iron content and stainable iron on day 5, in parallel with regeneration of hepatocytes. Histopathological lesions and hepatocellular iron accumulation disappeared until day 10. The hepcidin induction was preceded by activation of IL6/STAT3 pathway, whereas other pathways known to induce hepcidin were down-regulated. IL6 was expressed by MHC class II-positive macrophages in the portal area, suggestive of dendritic cells. Our results suggest that IL6 released by portal macrophages may regulate hepatocyte hepcidin expression via STAT3 activation during transient iron overload in TAA-induced acute liver injury.

Topics: Animals; Blotting, Western; Chemical and Drug Induced Liver Injury; Gene Expression Regulation; Immunohistochemistry; Iron; Iron-Regulatory Proteins; Male; Rats; Rats, Inbred F344; Real-Time Polymerase Chain Reaction; Thioacetamide

MicroRNAs are small RNA molecules that post-transcriptionally regulate gene expression. MicroRNA-122 is the most abundant and specific liver microRNA. Hepatotoxicity involves a significant alteration of liver gene expression. The aim of this work was to evaluate the microRNA-122 regulatory network in models of hepatotoxicity induced by thioacetamide or carbon tetrachloride. We report that the toxins decreased the expression of microRNA-122, which corresponded with an increase in two target genes: Cyclin G1 and the cationic amino acid transporter CAT-1. We found a decreased expression of its precursor, pri-microRNA-122, and of the transcription factors that specifically bind its promoter: CCAAT/enhancer-binding protein alpha, and members of the hepatocyte nuclear factor family. Therefore, microRNA-122 expression levels are under transcriptional control during hepatotoxicity. We propose that the changes observed are associated with the liver response to cope with the injury caused by the hepatotoxins, likely through a cell proliferation process to repair the damaged tissue.

Topics: Animals; Carbon Tetrachloride; Cationic Amino Acid Transporter 1; CCAAT-Enhancer-Binding Protein-alpha; Chemical and Drug Induced Liver Injury; Cyclin D1; Cyclin G1; Cytochrome P-450 CYP2E1; Disease Models, Animal; Glutamate-Ammonia Ligase; Hepatocyte Nuclear Factor 4; Liver; Male; MicroRNAs; Proliferating Cell Nuclear Antigen; Rats; Rats, Wistar; RNA, Messenger; Thioacetamide; Transcription, Genetic

Mammalian thioredoxin reductases (TrxR) are selenoproteins with important roles in antioxidant defense and redox regulation, principally linked to functions of their main substrates thioredoxins (Trx). All major forms of TrxR are intracellular while levels in serum are typically very low.. Serum TrxR levels were determined with immunoblotting using antibodies against mouse TrxR1 and total enzyme activity measurements were performed, with serum and tissue samples from mouse models of liver injury, as triggered by either thioacetamide (TAA) or carbon tetrachloride (CCl4).. TrxR levels in serum increased upon treatment and correlated closely with those of alanine aminotransferase (ALT), an often used serum biomarker for liver damage. In contrast, Trx1, glutathione reductase, superoxide dismutase or selenium-containing glutathione peroxidase levels in serum displayed much lower increases than TrxR or ALT.. Serum TrxR levels are robustly elevated in mouse models of chemically induced liver injury.. The exaggerated TrxR release to serum upon liver injury may reflect more complex events than a mere passive release of hepatic enzymes to the extracellular milieu. It can also not be disregarded that enzymatically active TrxR in serum could have yet unidentified physiological functions.

Topics: Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Gene Expression Regulation, Enzymologic; Humans; Mice; Thioacetamide; Thioredoxin Reductase 1; Thioredoxins

The literature indicates that retinoids can influence the metabolism and actions of xenobiotics and conversely that xenobiotics can influence the metabolism and actions of retinoids. We were interested in understanding the degree to which hepatic retinoid stores, accumulated over a lifetime, affect xenobiotic metabolism, and actions. To investigate this, we induced liver injury through administration of the hepatotoxin thioacetamide (TAA) to chow fed wild type (WT) mice and lecithin:retinol acyltransferase-deficient (Lrat(-/-)) mice that are genetically unable to accumulate hepatic retinoid stores. Within 48 h of TAA-treatment, WT mice develop liver injury as evidenced by focal necrotic areas and increases in serum ALT activity and myeloperoxidase activity in hepatic parenchyma. Simultaneously, features of hepatic encephalopathy develop, as evidenced by a 25% increase in blood ammonia and a threefold reduction of blood glucose levels. This is accompanied by reduced hepatic glutathione, and increased thiobarbituric acid reactive substances, protein carbonyl and sulfhydryl groups, and increased cytochrome P450-catalyzed hydroxylation activity and flavin-containing monooxygenase activity in microsomes prepared from WT liver. Strikingly, none of these TAA-induced effects were observed for matched Lrat(-/-) mice. To confirm that TAA hepatotoxicity depends on retinoid availability, we administered, over 48 h, four oral doses of 3000 IU retinyl acetate each to the mice. This led to the development of hepatotoxicity in Lrat(-/-) mice that was similar in extent to that observed in WT mice. Our findings establish that endogenous hepatic retinoid stores can modulate the toxicity of TAA in mice.

Topics: Acyltransferases; Administration, Oral; Animals; Chemical and Drug Induced Liver Injury; Diterpenes; Male; Mice, Inbred C57BL; Mice, Knockout; Microsomes, Liver; Mixed Function Oxygenases; Oxidative Stress; Retinoids; Retinyl Esters; Thioacetamide; Vitamin A

Activation of the renin angiotensin system resulting in stimulation of angiotensin-II (AngII) type I receptor (AT1R) is an important factor in the development of liver fibrosis. Here, we investigated the role of Janus kinase 2 (JAK2) as a newly described intracellular effector of AT1R in mediating liver fibrosis. Fibrotic liver samples from rodents and humans were compared to respective controls. Transcription, protein expression, activation, and localization of JAK2 and downstream effectors were analyzed by real-time polymerase chain reaction, western blotting, immunohistochemistry, and confocal microscopy. Experimental fibrosis was induced by bile duct ligation (BDL), CCl4 intoxication, thioacetamide intoxication or continuous AngII infusion. JAK2 was inhibited by AG490. In vitro experiments were performed with primary rodent hepatic stellate cells (HSCs), Kupffer cells (KCs), and hepatocytes as well as primary human and human-derived LX2 cells. JAK2 expression and activity were increased in experimental rodent and human liver fibrosis, specifically in myofibroblastic HSCs. AT1R stimulation in wild-type animals led to activation of HSCs and fibrosis in vivo through phosphorylation of JAK2 and subsequent RhoA/Rho-kinase activation. These effects were prevented in AT1R(-/-) mice. Pharmacological inhibition of JAK2 attenuated liver fibrosis in rodent fibrosis models. In vitro, JAK2 and downstream effectors showed increased expression and activation in activated HSCs, when compared to quiescent HSCs, KCs, and hepatocytes isolated from rodents. In primary human and LX2 cells, AG490 blocked AngII-induced profibrotic gene expression. Overexpression of JAK2 led to increased profibrotic gene expression in LX2 cells, which was blocked by AG490.. Our study substantiates the important cell-intrinsic role of JAK2 in HSCs for development of liver fibrosis. Inhibition of JAK2 might therefore offer a promising therapy for liver fibrosis.

Topics: Angiotensin II; Animals; Bile Ducts; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Hepatic Stellate Cells; Humans; Janus Kinase 2; Ligation; Liver Cirrhosis; Mice; Mice, Inbred C57BL; Mice, Knockout; Myofibroblasts; Phosphorylation; Rats; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Signal Transduction; Thioacetamide

Liver cirrhosis is the final consequence of a progressive fibrotic process characterized by excessive collagen deposition and destruction of the normal liver architecture. This study aimed to investigate the protective effects of curcumin, silybin-phytosome and alpha-R-lipoic acid against thioacetamide-induced cirrhosis. Male rats were allocated into five groups of which one group received saline and served as normal control. Animals from groups 2-5 were treated with thioacetamide administered intraperitoneally at a dose of 200 mg/kg 3 times per week for 7 weeks. Group 2 was left untreated while groups from 3 to 5 were given a daily oral dose of curcumin, silybin-phytosome or alpha-R-lipoic acid simultaneously with thioacetamide. Increases in hepatic levels of malondialdehyde (MDA) and protein carbonyls (Pr Co) associated with thioacetamide administration were partially blocked in those groups receiving supplements. Glutathione (GSH) depletion, collagen deposition, matrix metalloproteinase-2 (MMP-2) activity, transforming growth factor-β1 (TGF-β1) level as well as α-smooth muscle actin (α-SMA) and heat shock protein-47 (HSP-47) gene expressions were also decreased in response to supplements administration. Serological analysis of liver function and histopathological examination reinforced the results. In conclusion, the present study highlights the antioxidant and the antifibrotic potentials of these supplements against chronic liver diseases caused by ongoing hepatic damage.

Topics: Animals; Antioxidants; Biomarkers; Chemical and Drug Induced Liver Injury; Curcumin; Gene Expression Regulation; HSP47 Heat-Shock Proteins; Liver Cirrhosis; Male; Matrix Metalloproteinase 2; Oxidative Stress; Rats; Rats, Wistar; Silybin; Silymarin; Thioacetamide; Thioctic Acid; Transforming Growth Factor beta1

To improve the colonization rate of transplanted mesenchymal stem cells (MSCs) in the liver and effect of MSC transplantation for acute liver failure (ALF).. MSC was modified with the chemokine CXC receptor 4 (CXCR4) gene (CXCR4-MSC) or not (Null-MSC) through lentiviral transduction. The characteristics of CXCR4-MSCs and Null-MSCs were determined by real-time quantitative polymerase chain reaction, Western blotting and flow cytometry. CXCR4-MSCs and Null-MSCs were infused intravenously 24 h after administration of CCl4 in nude mice. The distribution of the MSCs, survival rates, liver function, hepatocyte regeneration and growth factors of the recipient mice were analyzed.. In vitro, CXCR4-MSCs showed better migration capability toward stromal cell-derived factor-1α and a protective effect against thioacetamide in hepatocytes. In vivo imaging showed that CXCR4-MSCs migrated to the liver in larger numbers than Null-MSCs 1 and 5 d after ALF. Higher colonization led to a longer lifetime and better liver function. Either CXCR4-MSCs or Null-MSCs exhibited a paracrine effect through secreting hepatocyte growth factor and vascular endothelial growth factor. Immunohistochemical analysis of Ki-67 showed increased cell proliferation in the damaged liver of CXCR4-MSC-treated animals.. Genetically modified MSCs expressing CXCR4 showed greater colonization and conferred better functional recovery in damaged liver.

Topics: Animals; Cell Line; Cell Movement; Cell Proliferation; Cell Survival; Cell Tracking; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Genetic Therapy; Green Fluorescent Proteins; Hepatocyte Growth Factor; Hepatocytes; Liver; Liver Failure, Acute; Liver Regeneration; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice, Nude; Paracrine Communication; Receptors, CXCR4; Thioacetamide; Time Factors; Transfection; Vascular Endothelial Growth Factor A

This study aimed to investigate the possible protective effects of genistein (GEN), a phytoestrogen, on the liver injury induced in rats by thioacetamide (TTA; 200.0 mg·(kg body mass)(-1); administered 3 times a week by intraperitoneal injection). GEN (0.5, 1.0, or 2.0 mg·(kg body mass)(-1); by subcutaneous injection) was concurrently administered on a daily basis for 8 weeks, and its effects were evaluated 24 h after the administration of the last dose. The results from this study revealed that TTA-induced liver injury was associated with massive changes in the serum levels of liver biomarkers, oxidative stress markers, and liver inflammatory cytokines. Treatment of TAA-induced liver injury in rats with GEN decreased the elevated serum levels of aspartate aminotransferase, alanine aminotransferase, and total and direct bilirubin, and increased the serum level of albumin. GEN also restored the liver levels of malondialdehyde and reduced glutathione, as well as tumor necrosis factor-alpha, interleukin-6, and their modulator nuclear factor kappa-light-chain-enhancer of activated B cells. From our results, it can be concluded that GEN attenuates the liver injury-induced in rats with TAA, and this hepatoprotective role is attributed to its anti-inflammatory and antioxidant properties.

Topics: Aneuploidy; Animals; Biomarkers; Body Weight; Chemical and Drug Induced Liver Injury; Cytokines; Genistein; Liver; NF-kappa B; Oxidative Stress; Phytoestrogens; Protective Agents; Rats, Wistar; Silymarin; Thioacetamide

Liver fibrosis is a complex disease in which several pathological processes, such as inflammation and angiogenesis, are closely integrated.. We hypothesised that treatment with the pharmacological agent, andrographolide (AP), which has multiple mechanisms of action, will provide a greater understanding of the role of AP during the multiple pathological processes that occur in advanced liver disease.. Liver fibrogenesis was induced in mice using thioacetamide (TAA), which was administrated for 6 weeks. Andrographolide (5, 20 or 100mg/kg) was then given once daily following TAA injection. Liver collagen was examined using hydroxyproline and α-SMA, while the inflammatory response was quantified by Western blot and RT-PCR assays. Liver angiogenesis, neutrophil infiltration and hypoxia were assessed using CD11b+, vWF and HIF-1α immunostaining. Mice with liver injuries that were treated with andrographolide showed improved inflammatory response and diminished angiogenesis and hepatic fibrosis. Andrographolide treatment inhibited liver neutrophil infiltration, while a decreased in TNF-α and COX-2 signalling indicated macrophage activation. Andrographolide decreased overall liver hypoxia, as shown by the downregulation of hypoxia-inducible cascade genes, such as VEGF. Andrographolide treatment resulted in a significant decrease in hepatic fibrogenesis, α-SMA abundance, and TGF-βR1 expression.. The present results suggest that multi-targeted therapies directed against angiogenesis, inflammation, and fibrosis should be considered for the treatment of advanced liver injury. They further suggest that andrographolide treatment may be a novel therapeutic agent for the treatment of liver disease.

Topics: Animals; Chemical and Drug Induced Liver Injury; Diterpenes; Liver; Liver Cirrhosis; Mice; Mice, Inbred BALB C; Neovascularization, Pathologic; Thioacetamide

Thioacetamide (TAA) is a potent hepatotoxin that causes centrilobulal necrosis and nephrotoxic damage following acute administration. Prolonged exposure to TAA can result in bile duct proliferation and liver cirrhosis histologically similar to that caused due to viral hepatitis infection. Coriander in food increases the antioxidant content, acting as a natural antioxidant and inhibiting undesirable oxidation processes. The present study investigated the antioxidant activity of Coriandrum sativum on TAA-induced hepatotoxicity in the male rats. Phenolic content and antioxidant activity were evaluated in the coriander leaves and seeds. Forty-eight adult male rats were divided into four groups. Group I (control), group II (TAA injected rats), group III (TAA injected rats fed coriander leaves) and group IV (TAA injected rats fed coriander seeds). The results revealed that serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities were significantly increased in the groups II, III and IV as compared to the normal control. Oxidative stress in the group II was manifested by a significant rise in nitric oxide (NO), thiobarbituric acid reactive substance (TBARS) levels and myloperoxidase (MPO) activities in the liver tissues as compared with the control group. Rats fed with coriander leaves and seeds showed a decrease in the serum ALT, AST and ALP activities and in the liver NO and TBARS levels as compared to the group II. Histopathological study revealed that coriander feeding attenuated TAA-induced hepatotoxicity in the rats. In conclusion, coriander leaves attenuate hepatotoxicity induced by TAA more than that of seeds due to the higher content of phenolic compounds and antioxidants in the leaves of coriander. Liver of rats intoxicated with TAA exhibited advanced CIRRHOSIS: in the form of macronodular and micronodular structure surrounded by fibrous tissue. Treatment with coriander leaves and seeds helps in improving the adverse effect of TAA-induced hepatotoxicity; also the histological study confirms this finding.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Antioxidants; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Coriandrum; Male; Oxidative Stress; Phytotherapy; Plant Leaves; Rats; Rats, Sprague-Dawley; Seeds; Thioacetamide

The aim of this study was to identify the hepatoprotective effects of reynosin, sesquiterpenes from the leaves of Laurus nobilis, against thioacetamide (TAA)-induced apoptosis in primary hepatocyte cultures and an in vivo mouse model. Rat hepatocytes were isolated and pretreated with 0.13, 0.64, or 3.22 μM reynosin and then exposed to 100 mM TAA. Reynosin treatment significantly inhibited TAA-induced apoptosis and hepatocellular DNA damage in primary rat hepatocytes. We observed an increase in levels of antiapoptotic Bcl-2, Bcl-XL mRNA and a decrease in levels of proapoptotic Bax mRNA following reynosin treatment of hepatocytes. Apoptosis in BALB/c mice was induced with intra-peritoneal injection of 200 mg/kg TAA for 2 weeks every other day. Then reynosin (5 mg/kg) and TAA were intragastrically given for 3 weeks every other day. Aspartate aminotransferase and alanine aminotransferase levels in the blood of mice were decreased in the reynosin administration group. Bcl-2 and Bcl-XL mRNA levels were increased, and the Bax mRNA level was decreased in reynosin-treated mice. Thus, reynosin inhibited TAA-induced apoptosis in primary hepatocytes and an in vivo mouse model.

Topics: Alanine Transaminase; Animals; Apoptosis; Apoptosis Regulatory Proteins; Aspartate Aminotransferases; Biomarkers; Cells, Cultured; Chemical and Drug Induced Liver Injury; Cytoprotection; Disease Models, Animal; Dose-Response Relationship, Drug; Gene Expression Regulation; Hepatocytes; Liver; Male; Mice; Mice, Inbred BALB C; Protective Agents; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sesquiterpenes; Thioacetamide

Hepatology research has focused on developing traditional therapies as pharmacological medicines to treat liver cirrhosis. Thus, this study evaluated mechanisms of the hepatoprotective activity of Curcuma longa rhizome ethanolic extract (CLRE) on thioacetamide-induced liver cirrhosis in rats.. The hepatoprotective effect of CLRE was measured in a rat model of thioacetamide-induced liver cirrhosis over 8 weeks. Hepatic cytochrome P450 2E1 and serum levels of TGF-β1 and TNF-α were evaluated. Oxidative stress was measured by malondialdehyde, urinary 8-hydroxyguanosine and nitrotyrosine levels. The protective activity of CLRE free-radical scavenging mechanisms were evaluated through antioxidant enzymes. Protein expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins in animal blood sera was studied and confirmed by immunohistochemistry of Bax, Bcl2 proteins and proliferating cell nuclear antigen.. Histopathology, immunohistochemistry and liver biochemistry were significantly lower in the Curcuma longa-treated groups compared with controls. CLRE induced apoptosis, inhibited hepatocytes proliferation but had no effect on hepatic CYP2E1 levels.. The progression of liver cirrhosis could be inhibited by the antioxidant and anti-inflammatory activities of CLRE and the normal status of the liver could be preserved.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Apoptosis; Cell Proliferation; Chemical and Drug Induced Liver Injury; Curcuma; Cytochrome P-450 CYP2E1; Disease Models, Animal; Hepatocytes; Liver; Liver Cirrhosis, Experimental; Malondialdehyde; Oxidative Stress; Phytotherapy; Plant Extracts; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Rhizome; Thioacetamide; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha

Apoferritin has been exploited to deliver simultaneously therapeutic and imaging agents (loaded into its internal cavity) to hepatocytes as this protein is efficiently taken up from blood by hepatocyte scavenger receptor class A type 5 via the ferritin transporting route. To this purpose the protein has been loaded with the magnetic resonance imaging (MRI) contrast agent GdHPDO3A and curcumin, a polyphenolic substance endowed with multiple pharmacological actions, namely: antioxidant, anti-inflammatory, antineoplastic. Curcumin and GdHPDO3A loaded apoferritin has been used with the aim to attenuate the thioacetamide-induced hepatitis together with the evaluation by MRI of drug delivery efficiency. Mice pretreated by intraperitoneal administration showed significantly attenuated hepatic injury as assessed by measuring alanine aminotransferase (ALT) activity in plasma and by histology assessment. The encapsulation of curcumin inside the apoferritin cavity significantly increases its stability and bioavailability while maintaining its therapeutic anti-inflammatory properties.

Topics: Alanine Transaminase; Animals; Anti-Inflammatory Agents; Antioxidants; Apoferritins; Chemical and Drug Induced Liver Injury; Contrast Media; Curcumin; Drug Carriers; Drug Delivery Systems; Gadolinium; Heterocyclic Compounds; Magnetic Resonance Imaging; Male; Mice; Mice, Inbred C57BL; Organometallic Compounds; Thioacetamide

Recent work has demonstrated the importance of post-transcriptional gene regulation in toxic responses. In the present study, we used two rat models to investigate mRNA translation in the liver following xenobiotic-induced toxicity. By combining polysome profiling with genomic methodologies, we were able to assess global changes in hepatic mRNA translation. Dio3 (iodothyronine deiodinase type III) was identified as a gene that exhibited specific translational repression and had a functional role in a number of relevant canonical pathways. Western blot analysis indicated that this repression led to reduced D3 (the protein expressed by Dio3) levels, enhanced over time and with increased dose. Using Northern blotting techniques and qRT-PCR (quantitative reverse transcription-PCR), we confirmed further that there was no reduction in Dio3 mRNA, suggesting that translational repression of Dio3 is an important determinant of the reduced D3 protein expression following liver damage. Finally, we show that drug-induced hepatotoxicity appears to cause localized disruptions in thyroid hormone levels in the liver and plasma. We suggest that this leads to reduced translation of Dio3 mRNA, which results in decreased D3 production. It may therefore be possible that this is an important mechanism by which the liver can, upon early signs of damage, act rapidly to maintain its own energy equilibrium, thereby avoiding global disruption of the hypothalamic-pituitary-thyroid axis.

Topics: Animals; Chemical and Drug Induced Liver Injury; Gene Expression Regulation; Iodide Peroxidase; Liver; Male; Rats; Rats, Wistar; RNA, Messenger; Thioacetamide; Thyroxine; Triiodothyronine

Hepatic stellate cells (HSCs), which can express glial fibrillary acidic protein (GFAP) in normal rat livers, play important roles in hepatic fibrogenesis through the conversion into myofibroblasts (MFs). Cellular properties and possible derivation of GFAP-expressing MFs were investigated in thioacetamide (TAA)-induced rat liver injury and subsequent fibrosis. Seven-week-old male F344 rats were injected with TAA (300mg/kg BW, once, intraperitoneally), and were examined on post single injection (PSI) days 1-10 by the single and double immunolabeling with MF and stem cell marker antibodies. After hepatocyte injury in the perivenular areas on PSI days 1 and 2, the fibrotic lesion consisting of MF developed at a peak on PSI day 3, and then recovered gradually by PSI day 10. MFs expressed GFAP, and also showed co-expressions such cytoskeletons (MF markers) as vimentin, desmin and α-SMA in varying degrees. Besides MFs co-expressing vimentin/desmin, desmin/α-SMA or α-SMA/vimentin, some GFAP positive MFs co-expressed with nestin or A3 (both, stem cell markers), and there were also MFs co-expressing nestin/A3. However, there were no GFAP positive MFs co-expressing RECA-1 (endothelial marker) or Thy-1 (immature mesenchymal cell marker). GFAP positive MFs showed the proliferating activity, but they did not undergo apoptosis. However, α-SMA positive MFs underwent apoptosis. These findings indicate that HSCs can proliferate and then convert into MFs with co-expressing various cytoskeletons for MF markers, and that the converted MFs may be derived partly from the stem cell lineage. Additionally, well-differentiated MFs expressing α-SMA may disappear by apoptosis for healing. These findings shed some light on the pathogenesis of chemically induced hepatic fibrosis.

Topics: Animals; Chemical and Drug Induced Liver Injury; Glial Fibrillary Acidic Protein; Hepatic Stellate Cells; Immunohistochemistry; In Situ Nick-End Labeling; Male; Myofibroblasts; Rats; Rats, Inbred F344; Real-Time Polymerase Chain Reaction; Thioacetamide

The liver plays an essential role in the body by regulating several important metabolic functions. Liver injury is associated with the distortion of these functions causing many health problems. Pharmaceutical drugs treat liver disorders but cause further damage to it. Hence, herbal drugs are used worldwide and are becoming increasingly popular.. The hepatoprotective activity of Phyllanthus niruri (PN) was evaluated against liver cirrhosis induced by thioacetamide (TAA) in male Sprague Dawley rats. Rats received intraperitoneal injections of thioacetamide (TAA, 200 mg/kg, b.w. three times weekly) for eight weeks. Daily treatments with plant extract (200 mg/kg) were administered orally for eight weeks. At the end of the study, hepatic damage was evaluated by monitoring transforming growth factor (TGFβ), collagen α1 (Collα1), matrix metalloproteinase-2 (MMP2) and tissue inhibitor of matrix metalloproteinase-1 (TIMP1) gene expression by real-time PCR. Moreover, different chromatographic techniques including column chromatography, thin layer chromatography, and Ultra Performance Liquid Chromatography (UPLC) with Liquid Chromatography/Mass Spectrometry (LC/MS) were used to isolate the active constituents of the plant.. The results revealed that treatment with PN significantly reduced the effect of thioacetamide toxicity and exhibited effective hepatoprotective activity. The mechanism of the hepatoprotective effect of PN is proposed to be by normalizing ROSs. Additionally, PN treatment regulated the expression of TGFβ, Collα1, MMP2, and TIMP1 genes. In the active fraction of P. niruri, the isolated chemical constituents were 4-O-caffeoylquinic acid and quercetin 3-O-rhamnoside.. The results of the present study indicate that PN ethanol extracts possess hepatoprotective activity that is most likely because of the isolated chemical constituents.

Topics: Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Gene Expression Profiling; Liver; Liver Cirrhosis; Male; Matrix Metalloproteinase 2; Phyllanthus; Phytotherapy; Plant Extracts; Quercetin; Quinic Acid; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Thioacetamide; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta

The present study was designed to investigate the protective effects of carvacrol against thioacetamide (TAA)-induced oxidative stress, inflammation and apoptosis in liver of Wistar rats. In this study, rats were subjected to concomitant prophylactic oral pretreatment of carvacrol (25 and 50 mg kg(-1) body weight (b.w.)) against the hepatotoxicity induced by intraperitoneal administration of TAA (300 mg kg(-1) b.w.). Efficacy of carvacrol against the hepatotoxicity was evaluated in terms of biochemical estimation of antioxidant enzyme activities, histopathological changes, and expressions of inflammation and apoptosis. Carvacrol pretreatment prevented deteriorative effects induced by TAA through a protective mechanism in a dose-dependent manner that involved reduction of oxidative stress, inflammation and apoptosis. We found that the protective effect of carvacrol pretreatment is mediated by its inhibitory effect on nuclear factor kappa B activation, Bax and Bcl-2 expression, as well as by restoration of histopathological changes against TAA administration. We may suggest that carvacrol efficiently ameliorates liver injury caused by TAA.

Topics: Alanine Transaminase; Animals; Anti-Inflammatory Agents; Apoptosis; Aspartate Aminotransferases; bcl-2-Associated X Protein; Chemical and Drug Induced Liver Injury; Cymenes; Glutathione; Glutathione Peroxidase; Glutathione Reductase; Inflammation; L-Lactate Dehydrogenase; Liver; Male; Monoterpenes; NF-kappa B; Oxidative Stress; Protective Agents; Rats; Rats, Wistar; Thioacetamide; Xanthine Oxidase

The geographic map of cancer prevalence differs due to environmental and dietary factors in various populations. High prevalence of a number of cancers in some regions is thought to be attributed to local dietary habits. Dorema aucheri (Bilhar) is used commonly as an herbal medicine in some regions including Iran. The aim of this study was to evaluate whether Dorema aucheri has carcinogenic effects in albino mice or not.. The Dorema aucheri leaves were extracted by Soxhlet method and were injected intraperitoneally and randomly into 28 healthy albino mice which were divided into seven groups. One was put aside as the non-injected control group. The second control group was chosen to be injected by a known carcinogen. Another group was injected by carcinogen and then, Bilhar extract. The left four groups were injected the extracts in a dose- dependent manner, increasingly in the range of 0.4 - 3.2mL/kg. Extract injections were repeated every 48- hour intervals for three times. Then, liver and serum samples were analyzed biochemically and pathologically.. The pathologic and biochemical studies showed that the injection of plant extracts caused necrosis, inflammation of the liver tissue, cell proliferation, cholestasis, and there were significant increases in release of liver enzymes [ALP, ALT (SGPT) and AST (SGOT)] and bilirubin compared to the non-injected control group. The level of liver damage was dose dependent.. Dorema aucheri has potential hepatotoxic capacities and possibly this may be related to the high prevalence of cancer in some regions of Iran.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Apiaceae; Aspartate Aminotransferases; Bilirubin; Carcinogens; Cell Proliferation; Chemical and Drug Induced Liver Injury; Cholestasis; Hepatitis; Injections, Intraperitoneal; Liver; Mice; Necrosis; Plant Leaves; Plant Preparations; Thioacetamide

Silybin (SB), a major constituent of the milk thistle, has been used to treat several liver disorders. However, liver diseases were always accompanied by CYP450 dysfunction. This study was designed to explore the relationship between the hepatoprotective effect and CYP3A regulation of SB during thioacetamide (TAA)-induced rat liver injury.. Serum biochemical analysis and histopathological study were taken to evaluate the hepatoprotectinve effect of SB. α-SMA were detected by immunohistochemical analysis and cytokine release in rat liver was determined by ELISA assay. CYP3A and PXR expression were determined by RT-PCR and Western blot analysis, and CYP3A activity was based on the midazolam 4-hydroxylation reaction. Also, siRNA transfection was induced in HepG2 cells to evaluate the effect of PXR on cytotoxicity and CYP3A4 dysregulation caused by TAA.. SB showed powerful hepatoprotective effects, and anti-inflammatory and anti-fibrosis effects, and reversed the loss of CYP3A and PXR in TAA-injured rat liver, and decreased PXR translocation into the cell nucleus. PXR silencing weakened the effect of SB on cytoprotection and CYP3A regulation.. PXR was a very important factor of CYP3A regulation and might be the target of SB in TAA-induced liver disease. Also, because of the potential interactions of SB and co-administered medicines, it might be necessary to adjust the dosage in the clinical medication of liver disease.

Topics: Animals; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP3A; Drugs, Chinese Herbal; Liver; Male; Pregnane X Receptor; Rats; Rats, Sprague-Dawley; Receptors, Steroid; Signal Transduction; Silybin; Silybum marianum; Silymarin; Thioacetamide

Our purpose in this study was to apply an empirical mathematical model (EMM) to the quantitative evaluation of thioacetamide (TAA)-induced acute liver injury in rats by use of dynamic contrast-enhanced computed tomography (DCE-CT), and to investigate its usefulness in comparison with a dual-input, single-compartment model. The rats in the TAA-treated group were injected intravenously with 140 mg/kg body weight (n = 10) or 280 mg/kg body weight (n = 10) of TAA, whereas those in the control group (n = 10) were injected with saline instead of TAA. The DCE-CT studies were performed 2 days after injection of TAA or saline by use of a 4-detector row CT. The upper limit of the time-density curve (A), the rates of contrast uptake (α) and washout (β), the parameter related to the slope of early uptake (q), the area under the curve (AUC), the time to the maximum enhancement (T (max)), the maximum enhancement (C (Lmax)), and the elimination half-life of the contrast agent (T (1/2)) were calculated by use of the EMM. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also measured. Both α and q decreased significantly in the rats of the TAA-treated group compared to those in the control group, whereas T (max) and T (1/2) increased significantly. The values of α, q, AUC, and T (max) were significantly correlated with both AST and ALT. Our results suggest that the EMM is useful for quantitative evaluation of TAA-induced acute liver injury and can be used as an alternative to the dual-input single-compartment model, especially when the vascular input functions cannot be obtained.

Topics: Animals; Chemical and Drug Induced Liver Injury; Contrast Media; Male; Models, Biological; Rats; Rats, Wistar; Thioacetamide; Tomography, X-Ray Computed

Kynurenine aminotransferase II (KAT-II) is the astrocytic enzyme catalyzing the synthesis of kynurenic acid (KYNA), an endogenous inhibitor of the α7-nicotinic receptor and the NMDA receptor (NMDAr). A previous study demonstrated an increase of KYNA synthesis in the brain of rats with thioacetamide (TAA)-induced acute liver failure. Here we show that TAA administration increases KAT-II expression in the rat cerebral cortex and the effect is mimicked in cerebral cortical astrocytes in culture treated with high (5 mM) concentration of ammonia. KAT-II expression in control and TAA-treated rats was increased by NMDAr antagonist memantine, and the effects of TAA and memantine appeared additive. In astrocytes, the NMDAr antagonist MK-801 raised KAT-II expression as well, while NMDA added alone had no effect. Glutamate decreased KAT-II mRNA level, which was attenuated by MK-801. The results suggest that stimulation of KAT-II expression during hepatic encephalopathy may be associated with a partial inactivation of astrocytic NMDAr by ammonia.

Topics: Ammonia; Analysis of Variance; Animals; Astrocytes; Brain Chemistry; Carcinogens; Chemical and Drug Induced Liver Injury; Dizocilpine Maleate; Excitatory Amino Acid Antagonists; Male; Memantine; Primary Cell Culture; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptors, N-Methyl-D-Aspartate; RNA, Messenger; Thioacetamide; Transaminases; Up-Regulation

Ionized calcium binding adaptor molecule 1 (Iba1) is associated with membrane ruffling and motility of cells. Galectin-3 (Gal-3) is a β-galactoside binding animal lectin, and regulates fibrogenesis probably through transforming growth factor-β1. To evaluate macrophage properties, expressions of Iba1 and Gal-3 were investigated, in relation to macrophages expressing CD68 (ED1; reflecting increased phagocytosis) and CD163 (ED2; implying proinflammatory factor productions) in centrilobular lesions induced in rat livers with thioacetamide (TAA; 300 mg/kg body weight, once intraperitoneally). In agreement with expression patterns of CD68(+) and CD163(+) macrophages, cells reacting to Iba1 and Gal-3 were increased in numbers on post-injection (PI) days 1-5, peaking on day 2; thereafter, the positive cells gradually decreased to control levels until PI days 7 and 10. The increased expressions of Iba1 and Gal-3 were confirmed at mRNA levels by the RT-PCR. Double immunofluorescence staining on PI days 2 and 3 demonstrated Iba1 expression in 15-46% of CD68(+) and CD163(+) macrophages, and Gal-3 expression in 65-82% of CD68(+) and CD163(+) macrophages; Gal-3 expression was observed in 84-93% of Iba1(+) cells. Interestingly, Gal-3 was also expressed in a small number of α-smooth muscle actin-positive myofibroblasts in fibrotic lesions developed in injured centrilobular areas. These findings indicate that macrophages with various functions can participate in development of liver lesions and resultant fibrosis. Besides CD68 and CD163, Iba1 and Gal-3 immunohistochemistry for macrophages would be useful to analyze the pathogenesis behind developing hepatotoxicity.

Topics: Acute Disease; Animals; Calcium-Binding Proteins; Chemical and Drug Induced Liver Injury; Fluorescent Antibody Technique; Galectin 3; Immunohistochemistry; Liver; Macrophages; Male; Microfilament Proteins; Microscopy, Confocal; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Thioacetamide

We successfully demonstrate the first solid-state sensor to have reliable responses to breath ammonia of rat. For thioacetamide (TAA)-induced hepatopathy rats, we observe that the proposed sensor can detect liver that undergoes acute-moderate hepatopathy with a p-value less than 0.05. The proposed sensor is an organic diode with vertical nanojunctions produced by using low-cost colloidal lithography. Its simple structure and low production cost facilitates the development of point-of-care technology. We also anticipate that the study is a starting point for investigating sophisticated breath-ammonia-related disease models.

Topics: Ammonia; Animals; Breath Tests; Chemical and Drug Induced Liver Injury; Female; Nanostructures; Rats; Rats, Sprague-Dawley; Thioacetamide

To assess the In vivo antioxidFant and hepatoprotective activity of methanolic extract of Daucus carota (D. carota) seeds in experimental animals.. Methanolic extracts of D. carota seeds is used for hepatoprotection assessment. Oxidative stress were induced in rats by thioacetamide 100 mg/kg s.c, in four groups of rats (two test, standard and toxic control). Two test groups received D. carota seeds extract (DCSE) at doses of 200 mg/kg and 400 mg/kg. Standard group received silymarin (25 mg/kg) and toxic control received only thioacetamide. Control group received only vehicle. On the 8th day animals were sacrificed and liver enzyme like serum glutamic pyruvic transaminase (SGPT), serum glutamic-oxaloacetic transaminase (SGOT) and alkaline phosphatase (ALP) were estimated in blood serum and antioxidant enzyme like superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GRD), glutathione peroxidase (GPX), glutathione-S-transferase (GST) and lipid peroxidation (LPO) were estimated in liver homogenate.. A significant decrease in SGPT, SGOT and ALP levels was observed in all drug treated groups as compared to thioacetamide group (P < 0.001) and in case of antioxidant enzyme a significant (P < 0.001) increase in SOD, CAT, GRD, GPX and GST was observed in all drug treated groups as compared with thioacetamide group. But in case of LPO a significant (P < 0.001) reduction was observed as compared to toxic control group.. DCSE has contributed to the reduction of oxidative stress and the protection of liver in experimental rats.

Topics: Alanine Transaminase; Animals; Antioxidants; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Daucus carota; Disease Models, Animal; Glutathione; Glutathione Peroxidase; Lipid Peroxidation; Liver; Methanol; Oxidative Stress; Phytotherapy; Plant Extracts; Rats; Seeds; Superoxide Dismutase; Thioacetamide

To evaluate the protective effect of Pisonia aculeata (P. aculeata) on thioacetamide induced hepatotoxicity in rats.. Male Wistar rats were administered 250 or 500 mg/kg p.o. of P. aculeata extract for 21 days and simultaneously administered thioacetamide (TAA) 50 mg/kg bw s.c. 1 h after the respective assigned treatments every 72 h. At the end of all experimental methods, all the animals were sacrificed by cervical decapitation. Blood samples were collected. Serum was separated and analyzed for various biochemical parameters.. TAA induced a significant rise in aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), total bilirubin, gamma glutamate transpeptidase (GGTP), lipid peroxidase (LPO) with a reduction of total protein, superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione S-transferase (GST). Treatment of rats with different doses of plant extract (250 and 500 mg/kg) significantly (P<0.001) altered serum marker enzymes and antioxidant levels to near normal against TAA treated rats. The activity of the extract at a dose of 300 mg/kg was comparable to the standard drug, silymarin (50 mg/kg, p.o.).. It can be concluded that P. aculeata extract possesses a remarkable hepatoprotective and antioxidant activity against TAA induced hepatotoxicity. More research is required to derive an optimal therapeutic dose.

Topics: Animals; Antioxidants; Blood Chemical Analysis; Chemical and Drug Induced Liver Injury; Enzymes; Gastrointestinal Agents; Histocytochemistry; Liver; Liver Function Tests; Male; Nyctaginaceae; Plant Extracts; Rats, Wistar; Thioacetamide; Treatment Outcome

To evalueate hepatoprotective effects Feronia elephantum (F. elephantum) correa against thioacetamide (TA) induced liver necrosis in diabetic rats.. Male wistar rats were made diabetic with alloxan (160 mg/kg) on day 0 of the study. They were intoxicated with hepatotoxicant (thioacetamide, 300 mg/kg, ip) on day 9 of study to produce liver necrosis. Effects of 7 day daily once administration (day 2 to day 9) of EF (400 and 800 mg/kg, po) were evaluated on necorosis of liver in terms of mortality, liver volume, liver weight, serum aspartate aminotransferase (AST) and serum alanine transaminase (ALT), and histopathology of liver sections (for signs of necorosis and inflammation) on day-9 of the study. Separate groups of rats with treated only with alloxan (DA control), thioacetamide (TA control) and both (TA+DA control) were maintained.. FE significantly lowered the mortality rate and showed improvement in liver function parameters in TA-induced diabetic rats without change in liver weight, volume and serum glucose levels.. FE showed promising activity against TA-induced liver necorsis in diabetic rats and so might be useful for prevention of liver complications in DM.

Topics: Animals; Blood Glucose; Chemical and Drug Induced Liver Injury; Diabetes Mellitus, Experimental; Disease Models, Animal; Liver Function Tests; Male; Necrosis; Plant Extracts; Protective Agents; Rats; Rutaceae; Thioacetamide

A comparison of analysis in evaluating the hepatoprotective action of fractional ethanolic (F0), ethyl acetic (F1), n-butanol (F2) and aqueous (F3) extracts of E. ulmoides Oliv. (EUO) against thioacetamide (TAA) induced hepatic damage was studied in mice. The extract (453 mg/kg-F0, 104 mg/kg-F1, 95 mg/kg-F2 and 237 mg/kg-F3 body weight, po, once daily for 15 days) restored serum marker enzymes levels to normal in TAA treated mice. The biochemical biomarkers viz., total protein, albumin and total bilirubin were also restored forward normal level expression pattern of liver protein profile of mice by using sodium dodecyl sulfate polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis showed 144 spots in TAA administered group which were significantly reduced in EUO extracts treated group. Among the four extracts ethyl acetate (F1) and n-butanol (F2) extracts showed more significant liver protection. TAA induced injury can be correlated with its high phenolic content in these extracts which may have hepatoprotective effects in regulating liver proteins by scavenging free radicals.

Topics: Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Drug Evaluation, Preclinical; Drugs, Chinese Herbal; Electrophoresis, Gel, Two-Dimensional; Eucommiaceae; Free Radical Scavengers; Liver; Liver Cirrhosis, Experimental; Mice; Phenols; Phytotherapy; Solvents; Superoxides; Thioacetamide

We undertook this study to investigate the usefulness of a dual-input single-compartment model for evaluating thioacetamide (TAA)-induced acute liver injury in rats by use of dynamic contrast-enhanced computed tomography (DCE-CT). The rats in the TAA-treated group were injected intravenously with 140 mg/kg (n = 10) or 280 mg/kg (n = 10) of TAA, whereas those in the control group (n = 10) were injected with saline. The rate constants for the transfer of the contrast agent from the hepatic artery to the liver (K(1a)), from the portal vein to the liver (K(1p)), and from the liver to the blood (k₂), as well as liver perfusion (LP), the arterial fraction of LP (AFLP), distribution volume (DV), and mean transmit time (MTT) were estimated with use of the dual-input single-compartment model. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also measured. K(1p), k₂, and LP decreased significantly in the TAA-treated group compared to those in the control group, whereas K(1a), AFLP, DV, and MTT increased significantly. The above parameters except for K (1a) were significantly correlated with both AST and ALT. We concluded that DCE-CT using the dual-input single-compartment model is useful for quantitative evaluation of TAA-induced acute liver injury.

Topics: Acute Disease; Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Contrast Media; Feasibility Studies; Male; Models, Biological; Rats; Rats, Wistar; Thioacetamide; Tomography, X-Ray Computed

Development of fibrosis is part of the pathophysiologic process of chronic liver disease. Although it is considered deleterious, it also represents a form of tissue repair. Deposition of extracellular matrix changes the cellular environment of the liver; we investigated whether it increases resistance to noxious stimuli and the role of changes in intracellular signaling to hepatocytes in mediating this effect.. Primary cultures of mouse hepatocytes were exposed to type I collagen (COL1); cell injury was assessed by morphologic and biochemical criteria. The expression of Bcl-2 family members was evaluated by immunoblot analyses. Activation of extracellular signal-regulated kinase (ERK) was assessed using phospho-specific antibodies. Liver fibrosis was induced by repeated administration of thioacetamide or carbon tetrachloride to mice; mice were then exposed to Fas antibodies.. Hepatocytes exposed to COL1 were more resistant to a variety of hepatotoxins, in a dose-dependent manner, and had lower levels of Bad, Bid, and Bax proapoptotic proteins compared with control hepatocytes. Activation of ERK1/2 was stronger and quicker in hepatocytes exposed to COL1. The MEK1/2 inhibitors U0126 and PD98059 reversed the protective effects of COL1 and the decrease in proapoptotic proteins. Hepatocytes isolated from ERK1(-/-) mice were insensitive to the protective effect of COL1. Fibrotic livers from wild-type mice had high levels of phospho-ERK1 and were resistant to Fas-induced cell death. ERK1(-/-) mice lost this effect.. Production of COL1 during liver fibrosis induces a hepatoprotective response that is mediated by activation of ERK1 signaling.

Topics: Acute Disease; Animals; Apoptosis; bcl-2-Associated X Protein; bcl-Associated Death Protein; BH3 Interacting Domain Death Agonist Protein; Blotting, Western; Carbon Tetrachloride; Cells, Cultured; Chemical and Drug Induced Liver Injury; Collagen Type I; Cytoprotection; Enzyme Activation; fas Receptor; Liver; Liver Cirrhosis, Experimental; MAP Kinase Kinase 1; MAP Kinase Kinase 2; Mice; Mice, Inbred BALB C; Mice, Knockout; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Phosphorylation; Protein Kinase Inhibitors; Signal Transduction; Thioacetamide; Time Factors

Liver fibrosis is chronic liver damage usually caused by alcohol, viruses or other toxins and is characterised by an excessive accumulation of extracellular matrix proteins such as collagen. The aim of this study was to establish an animal model of chronic liver damage and investigate molecular mechanisms of silymarin hepatoprotective effects.. Thioacetamide (TAA; 100 mg kg(-1) intraperitoneal (i.p.) injection three times weekly) effectively induced chronic liver fibrosis in male ICR mice. Then 24 ICR mice were randomly divided into four groups: (1) saline (i.p.) + water (gavage); (2) saline (i.p.) + 150 mg kg(-1) silymarin (gavage); (3) 100 mg kg(-1) TAA (i.p.) + water (gavage); (4) 100 mg kg(-1) TAA (i.p.) + 150 mg kg(-1) silymarin (gavage). Eight weeks of TAA treatment resulted in lower body weight, serum cholesterol and triglycerides as well as increased liver size, ALT, AST and LDH values (P < 0.05). These TAA-induced effects were attenuated by silymarin (P < 0.05); therefore silymarin also ameliorated TAA-induced liver lesions. Effects of silymarin on TAA-induced chronic liver damage may be attributed to down-regulation of hepatic MMP-2, MMP-13, TIMP-1, TIMP-2, AP-1, KLF6, TGF-β1, α-SMA and COL-α1.. A mouse model of chronic liver fibrosis was successfully established by injecting 100 mg kg(-1) TAA three times weekly in male ICR mice. Meanwhile, silymarin showed hepatoprotection against TAA-induced damage.

Topics: Animals; Body Weight; Chemical and Drug Induced Liver Injury; Cholesterol; Chronic Disease; Disease Models, Animal; Down-Regulation; Liver; Liver Cirrhosis, Experimental; Male; Matrix Metalloproteinases; Mice; Mice, Inbred ICR; Organ Size; Phytotherapy; Plant Extracts; Random Allocation; Silybum marianum; Silymarin; Thioacetamide; Tissue Inhibitor of Metalloproteinases; Transcription Factor AP-1; Transforming Growth Factor beta1; Triglycerides

Collagen I deposition contributes to liver fibrosis, yet little is known about other factors that mediate this process. Fibromodulin is a liver proteoglycan that regulates extracellular matrix organization and is induced by fibrogenic stimuli. We propose that fibromodulin contributes to the pathogenesis of fibrosis by regulating the fibrogenic phenotype of hepatic stellate cells (HSCs).. We analyzed liver samples from patients with hepatitis C-associated cirrhosis and healthy individuals (controls). We used a coculture model to study interactions among rat HSCs, hepatocytes, and sinusoidal endothelial cells. We induced fibrosis in livers of wild-type and Fmod(-/-) mice by bile duct ligation, injection of CCl(4), or administration of thioacetamide.. Liver samples from patients with cirrhosis had higher levels of fibromodulin messenger RNA and protein than controls. Bile duct ligation, CCl(4), and thioacetamide each increased levels of fibromodulin protein in wild-type mice. HSCs, hepatocytes, and sinusoidal endothelial cells produced and secreted fibromodulin. Infection of HSCs with an adenovirus that expressed fibromodulin increased expression of collagen I and α-smooth muscle actin, indicating increased activation of HSCs and fibrogenic potential. Recombinant fibromodulin promoted proliferation, migration, and invasion of HSCs, contributing to their fibrogenic activity. Fibromodulin was sensitive to reactive oxygen species. HepG2 cells that express cytochrome P450 2E1 produced fibromodulin, and HSCs increased fibromodulin production in response to pro-oxidants. In mice, administration of an antioxidant prevented the increase in fibromodulin in response to CCl(4). Coculture of hepatocytes or sinusoidal endothelial cells with HSCs increased the levels of reactive oxygen species in the culture medium, along with collagen I and fibromodulin proteins; this increase was prevented by catalase. Fibromodulin bound to collagen I, but the binding did not prevent collagen I degradation by matrix metalloproteinase 13. Bile duct ligation caused liver fibrosis in wild-type but not Fmod(-/-) mice.. Fibromodulin levels are increased in livers of patients with cirrhosis. Hepatic fibromodulin activates HSCs and promotes collagen I deposition, which leads to liver fibrosis in mice.

Topics: Actins; Animals; Antioxidants; Carbon Tetrachloride; Case-Control Studies; Cell Movement; Cell Proliferation; Chemical and Drug Induced Liver Injury; Coculture Techniques; Collagen Type I; Endothelial Cells; Extracellular Matrix Proteins; Fibromodulin; Hep G2 Cells; Hepatic Stellate Cells; Hepatitis C; Hepatocytes; Humans; Liver; Liver Cirrhosis; Liver Cirrhosis, Biliary; Liver Cirrhosis, Experimental; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oxidative Stress; Proteoglycans; Rats; RNA, Messenger; Thioacetamide; Time Factors; Transfection; Up-Regulation

Drug-induced liver injury (DILI) limits the development and application of many therapeutic compounds and presents major challenges to the pharmaceutical industry and clinical medicine. Acetaminophen-containing compounds are among the most frequently prescribed drugs and are also the most common cause of DILI. Here we describe a pharmacological strategy that targets gap junction communication to prevent amplification of fulminant hepatic failure and acetaminophen-induced hepatotoxicity. We demonstrate that connexin 32 (Cx32), a key hepatic gap junction protein, is an essential mediator of DILI by showing that mice deficient in Cx32 are protected against liver damage, acute inflammation and death caused by liver-toxic drugs. We identify a small-molecule inhibitor of Cx32 that protects against liver failure and death in wild-type mice when co-administered with known hepatotoxic drugs. These findings indicate that gap junction inhibition could provide a pharmaceutical strategy to limit DILI and improve drug safety.

Topics: Acetaminophen; Animals; Boron Compounds; Chemical and Drug Induced Liver Injury; Connexins; Gap Junction beta-1 Protein; Gap Junctions; HeLa Cells; Humans; Liver Failure, Acute; Mice; Mice, Inbred C57BL; Protective Agents; Thioacetamide

Intestinal bacterial overgrowth (IBO) and increased mucosal permeability are suggested to increase bacterial translocation (BT) in liver injury. Rifaximin (RIF) is a minimally absorbed oral antimicrobial agent that restores gut microflora imbalance. The aim of the present study was to investigate the effects of RIF on BT frequency in thioacetamide (TAA)-induced liver injury. Group 1 was the control. In group 2 (TAA), rats received TAA daily for 3 days. In group 3 (TAA + RIF), RIF was commenced on the same day as the first dose of TAA. In group 4 (RIF), rats received only RIF. Ileal aspirate Escherichia coli counts were significantly lower in the TAA + RIF group than in TAA group. There was no difference in BT frequency between the TAA and TAA + RIF groups. Our results suggest that factors such as intestinal barrier dysfunction and impaired host immune shield, apart from IBO, play an important role in BT in this model.

Topics: Animals; Bacterial Load; Bacterial Translocation; Chemical and Drug Induced Liver Injury; Escherichia coli; Ileum; Liver; Male; Rats; Rats, Wistar; Rifamycins; Rifaximin; Thioacetamide

Oxidative stress plays important role in the development of acute liver failure. In this study, we investigated effects of allopurinol (AP) upon thioacetamide (TAA)-induced liver injury and the potential mechanisms leading to amelioration in inflammation with AP treatment. Acute liver failure was induced by intraperitoneal administration of TAA (300 mg/kg/day for 2 days). Thirty-five rats were divided into five groups as control (group 1), TAA (group 2), TAA + 25AP (group 3), TAA + 50 AP (group 4), and TAA + 100AP (group 5). The number of animals in each group was seven. At the end of the study, histopathological, biochemical, and western blot analysis were done. TAA treatment significantly increased serum levels of aminotransferases, liver malondialdehyde (MDA), nuclear factor-kappa B (NF-қB ), activator protein-1 (AP-1), tumor necrosis factor-alpha (TNF-α), cyclooxygenase-2 (COX-2) and interleukin-6 (IL-6) levels, and the necro-inflammation scores. Nevertheless, nuclear factor E2-related factor-2 and heme oxygenase-1 (HO-1) expressions in the liver were decreased by TAA. AP treatment significantly lowered the serum levels of aminotransferases (P < 0.01) and liver MDA, NF-κB, AP-1, TNF-α, COX-2, and IL-6 expressions (P < 0.05). Moreover, AP restored the liver Nrf2 and HO-1 expressions and improved the necro-inflammation scores significantly. AP improves oxidative stress-induced liver damage by regulating cellular redox-sensitive transcriptor factors and expression of pro-inflammatory and antioxidant defense mechanisms. AP probably exerts these beneficiary features by its free radical scavenging ability in a dose-dependent manner.

Topics: Allopurinol; Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Cyclooxygenase 2; Heme Oxygenase-1; Inflammation; Interleukin-6; Liver Failure, Acute; Male; Malondialdehyde; NF-E2-Related Factor 2; NF-kappa B; Oxidation-Reduction; Oxidative Stress; Rats; Rats, Wistar; Reactive Oxygen Species; Thioacetamide; Transaminases; Transcription Factor AP-1; Transcription Factors; Tumor Necrosis Factor-alpha

Hepatotoxicity is associated with major changes in liver gene expression induced by xenobiotic exposure. Understanding the underlying mechanisms is critical for its clinical diagnosis and treatment. MicroRNAs are key regulators of gene expression that control mRNA stability and translation, during normal development and pathology. The canonical technique to measure gene transcript levels is Real-Time qPCR, which has been successfully modified to determine the levels of microRNAs as well. However, in order to obtain accurate data in a multi-step method like RT-qPCR, the normalization with endogenous, stably expressed reference genes is mandatory. Since the expression stability of candidate reference genes varies greatly depending on experimental factors, the aim of our study was to identify a combination of genes for optimal normalization of microRNA and mRNA qPCR expression data in experimental models of acute hepatotoxicity. Rats were treated with four traditional hepatotoxins: acetaminophen, carbon tetrachloride, D-galactosamine and thioacetamide, and the liver expression levels of two groups of candidate reference genes, one for microRNA and the other for mRNA normalization, were determined by RT-qPCR in compliance with the MIQE guidelines. In the present study, we report that traditional reference genes such as U6 spliceosomal RNA, Beta Actin and Glyceraldehyde-3P-dehydrogenase altered their expression in response to classic hepatotoxins and therefore cannot be used as reference genes in hepatotoxicity studies. Stability rankings of candidate reference genes, considering only those that did not alter their expression, were determined using geNorm, NormFinder and BestKeeper software packages. The potential candidates whose measurements were stable were further tested in different combinations to find the optimal set of reference genes that accurately determine mRNA and miRNA levels. Finally, the combination of MicroRNA-16/5S Ribosomal RNA and Beta 2 Microglobulin/18S Ribosomal RNA were validated as optimal reference genes for microRNA and mRNA quantification, respectively, in rat models of acute hepatotoxicity.

Topics: Acetaminophen; Actins; Animals; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Galactosamine; Gene Expression; Gene Expression Profiling; Glyceraldehyde-3-Phosphate Dehydrogenases; Liver; MicroRNAs; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Small Nuclear; Thioacetamide

Thioacetamide is widely used in industry and is known to be one of the most potent hepatotoxicants in experimental animals. We investigated the involvement of flavin-containing monooxygenase (FMO)-dependent hepatic-neutrophil activation and the release of proinflammatory mediators in thioacetamide-induced hepatic injury in rats. Thioacetamide (100 mg/kg, intraperitoneally) increased, within 12 h, hepatic serum aspartate transferase and alanine transferase levels, tumor necrosis factor-α production, interleukin-1β and nitrite levels, and myeloperoxidase activity. Rabbit anti-neutrophil serum markedly inhibited all thioacetamide-altered parameters. In addition, FMO-competitive inhibitor methimazole reduced thioacetamide-induced myeloperoxidase activity, hepatic tumor necrosis factor-α, interleukin-1β, nitrite, inducible nitric oxide synthase, and hepatic damage in thioacetamide-treated rats. Thus, we conclude that FMO-dependent hepatic neutrophil activation initiates the release of proinflammatory mediators in thioacetamide-treated rats.

Topics: Animals; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Hepatitis; Male; Neutrophil Activation; Oxygenases; Rabbits; Rats; Rats, Wistar; Thioacetamide

Coffee intake has been inversely related to the incidence of liver diseases, although there are controversies on whether these beneficial effects on human health are because of caffeine or other specific components in this popular beverage. Thus, this study evaluated the protective effects of coffee or caffeine intake on liver injury induced by repeated thioacetamide (TAA) administration in male Wistar rats. Rats were randomized into five groups: one untreated group (G1) and four groups (G2-G5) treated with the hepatotoxicant TAA (200 mg/kg b.w., i.p.) twice a week for 8 weeks. Concomitantly, rats received tap water (G1 and G2), conventional coffee (G3), decaffeinated coffee (G4) or 0.1% caffeine (G5). After 8 weeks of treatment, rats were killed and blood and liver samples were collected. Conventional and decaffeinated coffee and caffeine intake significantly reduced serum levels of alanine aminotransferase (ALT) (p < 0.001) and oxidized glutathione (p < 0.05), fibrosis/inflammation scores (p < 0.001), collagen volume fraction (p < 0.01) and transforming growth factor β-1 (TGF-β1) protein expression (p ≤ 0.001) in the liver from TAA-treated groups. In addition, conventional coffee and caffeine intake significantly reduced proliferating cellular nuclear antigen (PCNA) S-phase indexes (p < 0.001), but only conventional coffee reduced cleaved caspase-3 indexes (p < 0.001), active metalloproteinase 2 (p ≤ 0.004) and the number of glutathione S-transferase placental form (GST-P)-positive preneoplastic lesions (p < 0.05) in the liver from TAA-treated groups. In conclusion, conventional coffee and 0.1% caffeine intake presented better beneficial effects than decaffeinated coffee against liver injury induced by TAA in male Wistar rats.

Topics: Animals; Caffeine; Caspase 3; Chemical and Drug Induced Liver Injury; Coffee; Collagen; Food Handling; Glutathione; Liver; Liver Cirrhosis; Male; Matrix Metalloproteinase 2; Oxidation-Reduction; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Random Allocation; Rats; Rats, Wistar; Thioacetamide; Transforming Growth Factor beta1

Chronic liver disease promotes hepatocellular injury involving apoptosis and triggers compensatory regeneration that leads to the activation of quiescent stellate cells in the liver. The deposition of extracellular matrix from activated myofibroblasts promotes hepatic fibrosis and the progression to cirrhosis with deleterious effects on liver physiology. The role of apoptosis signaling pathways in the development of fibrosis remains undefined. The aim of the current study was to determine the involvement of the caspase-8 homologue cellular FLICE-inhibitory protein (cFLIP) during the initiation and progression of fibrosis. Liver injury and fibrosis from carbon tetrachloride (CCl(4)) and thioacetamide (TAA) were examined in mice exhibiting a hepatocyte-specific deletion of cFLIP (flip(-/-)). Acute liver injury from CCl(4) and TAA were enhanced in flip(-/-) mice. This was accompanied by increased activation of caspase-3 and -9, pronounced phosphorylation of JNK, and decreased phosphorylation of Erk. Deletion of the cJun NH(2)-terminal kinase 2 (JNK2) in flip(-/-) mice protected from injury. Hepatic fibrosis was increased at baseline in 12-wk-old flip(-/-) mice, and progression of fibrosis from TAA was accelerated compared with the wild type. In conclusion, deletion of cFLIP in hepatocytes leads to increased fibrosis and accelerated fibrosis progression. This is accompanied by increased injury involving the activation of caspases and JNK2. Thus predisposition to liver injury involving increased hepatocellular apoptosis is a critical mediator of accelerated fibrogenesis, and prevention of liver injury will be a most important measure for patients with chronic liver disease.

Topics: Animals; Apoptosis; Carbon Tetrachloride; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 3; Caspase 9; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Disease Progression; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Genotype; Hepatocytes; Liver; Liver Cirrhosis; Male; Mice; Mice, Knockout; Mitogen-Activated Protein Kinase 9; Phenotype; Phosphorylation; Signal Transduction; Thioacetamide; Time Factors

The induction of prolonged choline-deprivation (CD) in rats receiving thioacetamide (TAA) is an experimental approach of mild hepatotoxicity that could resemble commonly presented cases in clinical practice (in which states of malnutrition and/or alcoholism are complicated by the development of other liver-associated diseases).. The present study aimed to investigate the time-dependent effects of a 30-, a 60- and a 90-day dietary CD and/or TAA administration on the adult rat liver histopathology and the serum markers of hepatic functional integrity.. Rats were divided into four main groups: (a) control, (b) CD, (c) TAA and (d) CD + TAA. Dietary CD was provoked through the administration of choline-deficient diet, while TAA administration was performed ad libitum through the drinking water (300 mg/l of drinking water).. Histological examination of the CD + TAA liver sections revealed micro- and macro-vesicular steatosis with degeneration and primary fibrosis at day 30, to extensive steatosis and fibrosis at day 90. Steatosis was mostly of the macrovesicular type, involving all zones of the lobule, while inflammatory infiltrate consisted of foci of acute and chronic inflammatory cells randomly distributed in the lobule. These changes were accompanied by gradually increasing mitotic activity, as well as by a constantly high alpha-smooth muscle actin immunohistochemical staining. The determination of hepatocellular injury markers such as the serum enzyme levels' of alanine aminotransferase and aspartate aminotransferase demonstrated a decrease at day 30 (they returned to control levels at days 60 and 90). However, the determination of those serum enzymes used for the assessment of cholestatic liver injury (gamma-glutamyltransferase, alkaline phosphatase) revealed a constant (time-independent) statistically-significant increase versus control values.. Long-term combined dietary CD and TAA administration could be a more realistic experimental approach to human liver diseases involving severe steatosis, fibrosis, stellate cell activation and significant regenerative hepatocellular response.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Choline; Choline Deficiency; Diet; Fatty Liver; Hepatic Stellate Cells; Liver Cirrhosis; Male; Rats; Thioacetamide

Tumor necrosis factor (TNF)-α antibodies have been shown to reduce liver damage in different models. We investigated the effects of infliximab (a TNF-α antibody) on liver damage in thioacetamide (TAA)-induced hepatotoxicity in rats. Group 1 (n = 8) was the control group. In group 2 (n = 8), the TAA group, the rats received 300 mg/kg intraperitoneal (ip) TAA daily for 2 days. In group 3 (n = 8), the TAA + Infliximab (INF) group, infliximab (5 mg/kg ip daily) was administered 48 hours before the first dose of TAA daily for 2 days and was maintained for 4 consecutive days. In group 4 (n = 8), the INF group, the rats received only ip infliximab (5 mg/kg) daily. Livers were excised for histopathological and biochemical tests (thiobarbituric-acid-reactive substances [TBARS], and myeloperoxidase [MPO]). Serum ammonia, aspartate transaminase (AST), alanine transaminase (ALT), TNF-α, liver TBARS and MPO levels, and liver necrosis and inflammation scores in the TAA group were significantly higher than in the control and INF groups (all p < 0.01). All parameters except AST were not significantly different between TAA and TAA + INF. In conclusion, our results suggest that oxidative stress plays an important role in TAA-induced hepatotoxicity, and infliximab does not improve oxidative liver damage.

Topics: Animals; Antibodies, Monoclonal; Antidotes; Chemical and Drug Induced Liver Injury; Drug Antagonism; Infliximab; Lipid Peroxidation; Liver; Liver Function Tests; Male; Oxidative Stress; Rats; Rats, Wistar; Thioacetamide; Tumor Necrosis Factor-alpha

Heat shock protein 25 (Hsp25), which has anti-inflammatory activity, was examined for the relationship of its expression to macrophage appearance in thioacetoamide (TAA)-induced rat acute hepatic lesions. TAA-induced lesions, consisting of hepatocyte coagulation necrosis and reactive macrophages, developed in the centrilobular areas. Macrophages immuno-reacting to ED1 (CD68; exudative macrophages) were mainly seen within the lesions, whereas macrophages reacting to ED2 (CD163; resident macrophages and Kupffer cells), which have abundant cytoplasm, appeared mainly in the periphery of the lesions. Hsp25-immunopositivity was seen in hepatocytes around the lesions in relation to ED1- and ED2-positive macrophages in and around the centrilobular lesions, respectively. Because macrophages appearing in early stages of hepatic lesions produce various pro-inflammatory factors, mRNA expressions of tumor necrosis factor-α (TNF-α), monocyte chemoattractant factor-1 (MCP-1) and osteopontin (OPN) were examined in relation to Hsp25 mRNA expression. Hsp25 mRNA expression generally was correlated with TNF-α, MCP-1 and OPN expressions, suggesting their direct or indirect association with Hsp25 expression. Thus, Hsp25 might have a cytoprotection function against macrophages appearing in hepatic lesions, and factors produced by macrophages in the very early stages of hepatic lesions may influence Hsp25 expression. Hsp25 expression should be useful as an index of anti-inflammatory action for evaluation of hepatotoxicants in vivo.

Topics: Animals; Chemical and Drug Induced Liver Injury; Chemokine CCL2; Disease Models, Animal; Hepatocytes; HSP27 Heat-Shock Proteins; Immunohistochemistry; Liver; Liver Function Tests; Macrophages; Male; Osteopontin; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; RNA, Messenger; Thioacetamide; Tumor Necrosis Factor-alpha

Several lines of evidence suggest that innate immunity plays a key role in hepatic fibrogenesis. To clarify the role of natural killer (NK) T cells in hepatic inflammation and fibrogenesis, we here investigated xenobiotics-induced liver injury and subsequent fibrogenesis in mice lacking mature NKT cells caused by genetic disruption of the CD1d molecule.. Male CD1d-knockout (KO) and wild-type (WT) mice were given repeated intraperitoneal injections of thioacetamide (TAA, 3times/week; 0.1-0.2mg/g BW) for up to 9 weeks, or a single intraperitoneal injection of CCl(4) (1 μl/g). Liver histology was evaluated, and expression levels of cytokines and matrix-related genes in the liver were quantitatively measured by real-time reverse transcription-polymerase chain reaction (RT-PCR).. Mortality following repeated injections of TAA was prevented almost completely in CD1d-KO mice. TAA-induced inflammatory responses and hepatocellular damage were markedly ameliorated in CD1d-KO mice. TAA-induced expression of smooth muscle α-actin (SMA) and transforming growth factor (TGF)β1 mRNA in the liver were also prevented largely in CD1d-KO mice. In fact, CD1d-KO mice developed minimal hepatic fibrosis after 9-weeks of administration of TAA, which caused overt bridging fibrosis in WT mice. Indeed, TAA-induced increases in α1(I)procollagen (COL1A1) and tissue inhibitor of matrix metalloproteinase (TIMP)-1 mRNA were blunted significantly in CD1d-KO mice. Similarly, acute CCl(4)-induced hepatic injury and subsequent profibrogenic responses were also reduced significantly in CD1d-KO mice.. These findings clearly indicated that CD1d-restricted NKT cells contribute to xenobiotics-induced hepatic inflammation, hepatocellular damage, and subsequent profibrogenic responses in the liver.

Topics: Animals; Antigens, CD1d; Base Sequence; Cell Death; Chemical and Drug Induced Liver Injury; Collagen Type I; Collagen Type I, alpha 1 Chain; Hepatocytes; Immunity, Innate; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; RNA, Messenger; Thioacetamide; Tissue Inhibitor of Metalloproteinase-1

In hepatic toxicity induced in rats by two injections of thioacetamide (TAA, 350 mg/kg with an interval of 8 hr), the action of quercetin was investigated. After 96 hr, TAA administration resulted in hepatic necrosis, significant increases in serum transaminase activity, and increases in hepatic lipoperoxidation. Thioacetamide-induced hepatotoxicity also showed changes in antioxidant enzymes in the liver of rats, with alterations in p-ERK 1/2 (phosphorylated extracellular-signal related kinase 1/2) as well as an imbalance between proapototic protein Bax and anti-apoptotic protein Bcl-2 expression. With administration of the flavonoid quercetin (50 mg/Kg i.p.) for four consecutive days following TAA, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity were close to normal values in rats. Histological findings suggested that quercetin had a preventive effect on TAA-induced hepatic necrosis. Quercetin treatment caused significant decreases in lipid peroxide levels in the TAA-treated rats, with some changes in antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Quercetin also inhibited the change of the p-ERK1/2 by TAA and significantly prevented the increase in Bax/Bcl-2 ratio, thus preventing apoptosis. Findings indicate that quercetin may have a preventive effect on TAA-induced hepatotoxicity by modulating the oxidative stress parameters and apoptosis pathway.

Topics: Alanine Transaminase; Animals; Antioxidants; Apoptosis; Apoptosis Regulatory Proteins; Aspartate Aminotransferases; bcl-2-Associated X Protein; Blotting, Western; Catalase; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Gene Expression Regulation; Glutathione Peroxidase; Lipid Peroxidation; Lipid Peroxides; Male; MAP Kinase Signaling System; Oxidative Stress; Phosphorylation; Quercetin; Rats; Rats, Wistar; Superoxide Dismutase; Thioacetamide

It is well known that gadolinium chloride (GD) attenuates drug-induced hepatotoxicity by selectively inactivating Kupffer cells. In the present study the effect of GD in reference to cell cycle and postnecrotic liver regeneration induced by thioacetamide (TA) in rats was studied. Two months male rats, intraveously pretreated with a single dose of GD (0.1 mmol/Kg), were intraperitoneally injected with TA (6.6 mmol/Kg). Samples of blood and liver were obtained from rats at 0, 12, 24, 48, 72 and 96 h following TA intoxication. Parameters related to liver damage were determined in blood. In order to evaluate the mechanisms involved in the post-necrotic regenerative state, the levels of cyclin D and cyclin E as well as protein p27 and Proliferating Cell Nuclear Antigen (PCNA) were determined in liver extracts because of their roles in the control of cell cycle check-points. The results showed that GD significantly reduced the extent of necrosis. Noticeable changes were detected in the levels of cyclin D1, cyclin E, p27 and PCNA when compared to those induced by thioacetamide. Thus GD pre-treatment reduced TA-induced liver injury and accelerated the postnecrotic liver regeneration. These results demonstrate that Kupffer cells are involved in TA-induced liver and also in the postnecrotic proliferative liver states.

Topics: Animals; Cell Cycle; Cell Cycle Checkpoints; Cell Proliferation; Chemical and Drug Induced Liver Injury; Cyclin D; Cyclin E; Gadolinium; Kupffer Cells; Liver; Liver Regeneration; Male; Necrosis; Proliferating Cell Nuclear Antigen; Rats; Rats, Wistar; Thioacetamide

Drug-induced liver injury is a major issue of concern and has led to the withdrawal of a significant number of marketed drugs. An understanding of structure-activity relationships (SARs) of chemicals can make a significant contribution to the identification of potential toxic effects early in the drug development process and aid in avoiding such problems. This process can be supported by the use of existing toxicity data and mechanistic understanding of the biological processes for related compounds. In the published literature, this information is often spread across diverse sources and can be varied and unstructured in quality and content. The current work has explored whether it is feasible to collect and use such data for the development of new SARs for the hepatotoxicity endpoint and expand upon the limited information currently available in this area. Reviews of hepatotoxicity data were used to build a structure-searchable database, which was analyzed to identify chemical classes associated with an adverse effect on the liver. Searches of the published literature were then undertaken to identify additional supporting evidence, and the resulting information was incorporated into the database. This collated information was evaluated and used to determine the scope of the SARs for each class identified. Data for over 1266 chemicals were collected, and SARs for 38 classes were developed. The SARs have been implemented as structural alerts using Derek for Windows (DfW), a knowledge-based expert system, to allow clearly supported and transparent predictions. An evaluation exercise performed using a customized DfW version 10 knowledge base demonstrated an overall concordance of 56% and specificity and sensitivity values of 73% and 46%, respectively. The approach taken demonstrates that SARs for complex endpoints can be derived from the published data for use in the in silico toxicity assessment of new compounds.

Topics: Chemical and Drug Induced Liver Injury; Databases, Factual; Humans; Structure-Activity Relationship; Tetracyclines; Thiophenes

Drug-induced liver injury (DILI) is one of the most important reasons for drug development failure at both preapproval and postapproval stages. There has been increased interest in developing predictive in vivo, in vitro, and in silico models to identify compounds that cause idiosyncratic hepatotoxicity. In the current study, we applied machine learning, a Bayesian modeling method with extended connectivity fingerprints and other interpretable descriptors. The model that was developed and internally validated (using a training set of 295 compounds) was then applied to a large test set relative to the training set (237 compounds) for external validation. The resulting concordance of 60%, sensitivity of 56%, and specificity of 67% were comparable to results for internal validation. The Bayesian model with extended connectivity functional class fingerprints of maximum diameter 6 (ECFC_6) and interpretable descriptors suggested several substructures that are chemically reactive and may also be important for DILI-causing compounds, e.g., ketones, diols, and α-methyl styrene type structures. Using Smiles Arbitrary Target Specification (SMARTS) filters published by several pharmaceutical companies, we evaluated whether such reactive substructures could be readily detected by any of the published filters. It was apparent that the most stringent filters used in this study, such as the Abbott alerts, which captures thiol traps and other compounds, may be of use in identifying DILI-causing compounds (sensitivity 67%). A significant outcome of the present study is that we provide predictions for many compounds that cause DILI by using the knowledge we have available from previous studies. These computational models may represent cost-effective selection criteria before in vitro or in vivo experimental studies.

Topics: Bayes Theorem; Chemical and Drug Induced Liver Injury; Humans; Ligands

Octanoate (also known as sodium octanoate), a medium-chain fatty acid metabolized in the liver, is a potential substrate for non-invasive breath testing of hepatic mitochondrial beta-oxidation.. We evaluated the 13C-octanoate breath test (OBT) for assessing injury in acute hepatitis and two rat models of liver cirrhosis, first testing octanoate absorption (per os or intraperitoneally (i.p.)) in normal rats. We then induced acute hepatitis with thioacetamide (300 mg/kg/i.p., 24-h intervals). Liver injury end points were serum aminotransferase levels and 13C-OBT (24 and 48 h following initial injection). Thioacetamide (200 mg/kg/i.p., twice per week, 12 weeks) was used to induce liver cirrhosis. OBT and liver histological assessment were performed every 4 weeks. Bile duct ligation (BDL) was used to induce cholestatic liver injury. We completed breath tests with 13C-OBT and 13C-methacetin (MBID), liver biochemistry, and liver histology in BDL and sham-operated rats (baseline, 6, 14, 20 days post-BDL).. Octanoate absorbs well by either route. Peak amplitudes and cumulative percentage dose recovered at 30 and 60 min (CPDR30/60), but not peak time, correlated with acute hepatitis. Fibrosis stage 3 at week 8 significantly correlated with each OBT parameter. Cholestatic liver injury (serum bilirubin, ALP, gamma-GT, liver histology) was associated with significant suppression of the maximal peak values and CPDR30/60, respectively (P<0.05),using MBID but not 13C-octanoate.. OBT is sensitive for potentially evaluating liver function in rat models of acute hepatitis and thioacetamide-induced liver cirrhosis but not in cholestatic liver injury. The MBID test may be better for evaluation of cholestatic liver disease in this model.

Topics: Acetamides; Acute Disease; Animals; Breath Tests; Caprylates; Carbon Dioxide; Carbon Isotopes; Chemical and Drug Induced Liver Injury; Cholestasis, Extrahepatic; Common Bile Duct; Disease Models, Animal; Ligation; Liver; Liver Cirrhosis, Experimental; Male; Predictive Value of Tests; Rats; Rats, Wistar; Thioacetamide; Time Factors

The present study investigated the preventive effect of eugenol, a naturally occurring food flavouring agent on thioacetamide (TA)-induced hepatic injury in rats. Adult male Wistar rats of body weight 150-180 g were used for the study. Eugenol (10.7 mg/kg b.w./day) was administered to rats by oral intubation for 15 days. TA was administered (300 mg/kg b.w., i.p.) for the last 2 days at 24h interval and the rats were sacrificed on the 16th day. Markers of liver injury (aspartate transaminase, alanine transaminase, alkaline phosphatase, gamma-glutamyl transferase and bilirubin), inflammation (myeloperoxidase, tumor necrosis factor-alpha and interleukin-6), oxidative stress (lipid peroxidation indices, protein carbonyl and antioxidant status) and cytochrome P4502E1 activity were assessed. Expression of cyclooxygenase-2 (COX-2) and the extent of DNA damage were analyzed using immunoblotting and comet assay, respectively. Liver injury and collagen accumulation were assessed using histological studies by hematoxylin and eosin and Masson trichrome staining. Rats exposed to TA alone showed increased activities of hepatocellular enzymes in plasma, lipid peroxidation indices, inflammatory markers and pro-inflammatory cytokines and decreased antioxidant status in circulation and liver. Hepatic injury and necrosis were also evidenced by histology. Eugenol pretreatment prevented liver injury by decreasing CYP2E1 activity, lipid peroxidation indices, protein oxidation and inflammatory markers and by improving the antioxidant status. Single-cell gel electrophoresis revealed that eugenol pretreatment prevented DNA strand break induced by TA. Increased expression of COX-2 gene induced by TA was also abolished by eugenol. These findings suggest that eugenol curtails the toxic effects of TA in liver.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Blotting, Western; Body Weight; Chemical and Drug Induced Liver Injury; Comet Assay; Cyclooxygenase 2; Cytochrome P-450 CYP2E1; Cytokines; DNA Damage; Enzymes; Eugenol; Lipid Peroxidation; Liver; Male; Organ Size; Peroxidase; Protective Agents; Rats; Rats, Wistar; Thioacetamide

Thioacetamide (TAA) is a hepatotoxin frequently used for experimental purposes which produces centrilobular necrosis after a single dose administration. In spite of the fact that oxidative stress seems to play a very important role in the mechanism of TAA-induced injury, the effect of TAA on hepatocytes in primary culture with respect to the influence on mitochondria has yet to be verified. Hepatocytes were incubated for 24h in a medium containing TAA (0-70 mmol/l). Glutathione content (GSH/GSSG), reactive oxygen species and malondialdehyde formation were assessed as markers of cell redox state. Toxicity was determined by lactate dehydrogenase leakage and WST-1 assay. The functional capacity of hepatocytes was evaluated from albumin and urea production. Mitochondrial metabolism was assessed by measuring mitochondrial membrane potential and oxygen consumption. Our results show that a profound decrease in the GSH level in hepatocytes precedes a sharp rise in endogenous ROS production. ROS production correlates with an increase in lipoperoxidation. Mitochondria are affected by TAA secondarily as a consequence of oxidative stress. Oxidation of the NADH-dependent substrates of respiratory Complex I is significantly more sensitive to the toxic action of TAA than oxidation of the flavoprotein-dependent substrate of Complex II. Mitochondria can also maintain their membrane potential better when they utilize succinate as a respiratory substrate. It appears that GSH should be depleted below a certain critical level in order to cause a marked increase in lipid peroxidation. Mitochondrial injury can then occur and cell death develops.

Topics: Animals; Cells, Cultured; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Hazardous Substances; Hepatocytes; L-Lactate Dehydrogenase; Liver; Male; Malondialdehyde; Membrane Potential, Mitochondrial; Oxidative Stress; Rats; Rats, Wistar; Reactive Oxygen Species; Thioacetamide

Thioacetamide (TA) is a commonly used drug that can trigger acute hepatic failure (AHF) through generation of oxidative stress. Vitamin D3 upregulated protein 1 (VDUP1) is an endogenous inhibitor of thioredoxin, a ubiquitous thiol oxidoreductase, that regulates cellular redox status. In this study, we investigated the role of VDUP1 in AHF using a TA-induced liver injury model. VDUP1 knockout (KO) and wild-type (WT) mice were subjected to a single intraperitoneal TA injection, and various parameters of hepatic injury were assessed. VDUP1 KO mice displayed a significantly higher survival rate, lower serum alanine aminotransferase and aspartate aminotransferase levels, and less hepatic damage, compared to WT mice. In addition, induction of apoptosis was decreased in VDUP1 KO mice, with the alteration of caspase-3 and -9 activities, Bax-to-Bcl-2 expression ratios, and mitogen activated protein kinase (MAPK) signaling pathway. Importantly, analysis of TA bioactivation revealed lower plasma clearance of TA and covalent binding of [¹⁴C]TA to liver macromolecules in VDUP1 KO mice. Furthermore, the level of oxidative stress was significantly less in VDUP1 KO mice than in their WT counterparts, as evident from lipid peroxidation assay. These results collectively indicate that VDUP1 deficiency protects against TA-induced acute liver injury via lower bioactivation of TA and antioxidant effects.

Topics: Animals; Apoptosis; Carrier Proteins; Chemical and Drug Induced Liver Injury; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Random Allocation; Thioacetamide; Thioredoxins

The aerial parts of Tephrosia purpurea (L.) pers. (Fabaceae) and stem bark of Tecomella undulata seem. (Bignoniaceae) are used for liver disorders in the traditional system of medicine.. To evaluate the hepatoprotective activity of aerial parts of Tephrosia purpurea and stem bark of Tecomella undulata against thioacetamide-induced hepatotoxicity.. Hepatotoxicity was induced in albino rats of either sex by subcutaneous injection of thioacetamide. Aqueous-ethanolic extract of aerial parts of Tephrosia purpurea (100, 300 and 500 mg/kg/day and ethanolic extract of stem bark of Tecomella undulata (200, 500 and 1000 mg/kg/day were evaluated.. Oral administration of Tephrosia purpurea at 500 mg/kg and Tecomella undulata at 1000 mg/kg resulted in a significant reduction in serum aspartate aminotransaminase (35% and 31%, respectively), alanine aminotransaminase (50% and 42%, respectively), gamma glutamyl transpeptidase (56% and 49%, respectively), alkaline phosphatase (46% and 37%, respectively), total bilirubin (61% and 48%, respectively) and liver MDA levels (65% and 50%, respectively), and significant improvement in liver glutathione (73% and 68%, respectively) when compared with thioacetamide damaged rats. Histology of the liver sections of the animals treated with the extracts also showed dose-dependent reduction of necrosis.. The present study demonstrates the hepatoprotective activity of the aerial parts of Tephrosia purpurea and stem bark of Tecomella undulata against thioacetamide-induced hepatotoxicity.

Topics: Animals; Bignoniaceae; Bilirubin; Chemical and Drug Induced Liver Injury; Female; Glutathione; Liver; Male; Malondialdehyde; Phytotherapy; Plant Bark; Plant Components, Aerial; Plant Extracts; Plant Stems; Protective Agents; Rats; Rats, Wistar; Tephrosia; Thioacetamide

Estimation of liver damage is important in the pathophysiological and toxicological study of liver disease. As a novel, non-invasive marker of liver damage, we studied the efficacy of urine bile acids (UBA) in a rat model of liver disease. Thioacetamide (TAA)-treated rats were used in this study. Single intraperitoneal administration of high-dose TAA induces severe damage to the liver, and thus is used as a model of acute hepatitis. Continuous administration of low-dose TAA yields mild damage to the liver, and induces cirrhosis and hepatic tumors. In this study, it was found that both acute and chronic administration of TAA was associated with a dose-dependent elevation of UBA. The elevation of UBA content correlated with the alteration of blood biochemical indicators, and UBA screening showed a remarkable ability to distinguish liver-damaged rats from healthy rats. In particular, UBA analysis was found to have high sensitivity, specificity, and positive predictive value for the screening of rats with abnormal serum alkaline phosphatase (ALP) activity due to chronic liver damage, which was confirmed to include cholestasis and subsequent cirrhosis by liver histological analysis. In conclusion, we demonstrated that measurement of UBA is a simple, non-invasive and effective method for the screening of cholestasis in TAA-treated rats. We suggest that UBA analysis may have potent applicability for monitoring the progress of liver damage in animal models of chronic liver disease, such as cirrhosis and hepatic encephalopathy.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Aspartate Aminotransferases; Bile Acids and Salts; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Drug Administration Schedule; Injections, Intraperitoneal; Liver Diseases; Male; Rats; Rats, Wistar; Thioacetamide

Macrophages are crucial in hepatic fibrogenesis. In acute hepatic necrosis induced in rats by a single injection of 300 mg/kg body weight (BW) of thioacetamide (TAA), macrophage properties were investigated using single or double immunohistochemistry. Macrophages reacting with anti-CD68, anti-CD163, or major histocompatibility complex (anti-MHC) class II antibody appeared in injured centrilobular areas on days 1-5 after injection. Increased expression of CD68 and CD163 reflect phagocytosis and production of pro-inflammatory factors, respectively. There were also macrophages double-positive to CD68/CD163, CD68/MHC class II, or CD163/MHC class II; of these, macrophages double-positive to CD68/MHC class II were most frequent, indicating that macrophages with enhanced phagocytic activity came to express MHC class II. The appearance of these macrophages corresponded to increased expression of mRNAs of monocyte chemoattractant protein-1 (MCP-1), a chemokine, on day 1, and TGF-beta1, a fibrogenic factor, on day 3. Some hepatic stellate cells (HSCs) in injured areas reacted with anti-MCP-1 antibody. To investigate the effects of MCP-1, we added MCP-1 to HS-P, a rat macrophage line. Addition of MCP-1 increased immunoexpression for CD68 and CD163 and up-regulated TGF-beta1 mRNA expression. Collectively, macrophages in acute hepatic necrosis may express different properties such as phagocytosis, MHC class II expression, and TGF-beta1 production; such expression may be influenced by MCP-1 produced by HSCs.

Topics: Analysis of Variance; Animals; Antigens, CD; Antigens, Differentiation; Antigens, Differentiation, Myelomonocytic; Cells, Cultured; Chemical and Drug Induced Liver Injury; Chemokine CCL2; Gene Expression Regulation; Hepatic Stellate Cells; Histocompatibility Antigens Class II; Immunohistochemistry; Liver; Liver Diseases; Macrophages; Male; Necrosis; Rats; Rats, Inbred F344; Receptors, Cell Surface; Thioacetamide; Transforming Growth Factor beta1

Cleome viscosa Linn. (Family Capparidaceae) is naturalised throughout the hot and moist parts of India. Fresh leaves of this plant are used very effectively for the treatment of jaundice in the folk medicines of the Bundelkhand region of India. The hepatoprotective activity of the ethanolic extract of leaves was investigated against thioacetamide-induced hepatotoxicity in rats. The test material was found to be effectively hepatoprotective, as evidenced by biochemical parameters and histopathological studies. The hepatoprotective effect of ethanolic extract was comparable to that of silymarin, a standard hepatoprotective agent. The results of the present study support the traditional beliefs of the hepatoprotective effects of C. viscosa Linn.

Topics: Animals; Chemical and Drug Induced Liver Injury; Cleome; Liver; Male; Microscopy; Plant Extracts; Plant Leaves; Rats; Silymarin; Thioacetamide

Hepatocellular carcinoma (HCC) is one of the common cancers worldwide, caused by Hepatitis C virus (HCV) and hepatotoxins. Here we report the development of HCC in wild type as well as HCV core protein (HCP)-transgenic zebrafish upon treatment with a hepatotoxin, thioacetamide (TAA). Two-fold accelerated HCC development could be achieved in the TAA-treated transgenic fish, that is, the progression of the disease in TAA-treated wild type zebrafish developed HCC in 12 weeks whereas that of HCP-transgenic zebrafish shortened the HCC progression to 6 weeks. Histopathological observation showed the specific pathological features of HCC. The HCC progression was confirmed through RT-PCR that revealed an up and down regulation of different marker genes at various stages of HCC progression such as, steatohepatitis, fibrosis and HCC. Moreover, HCV core protein expressed in the HCP-transgenic zebrafish and TAA synergistically accelerate the HCC development. It must be mentioned that, this is the first report revealing HCV core protein along with TAA to induce HCC in zebrafish, particularly, in a short period of time comparing to mice model. As zebrafish has already been considered as a good human disease model and in this context, this HCC-zebrafish model may serve as a powerful preclinical platform to study the molecular events in hepatocarcinogenesis, therapeutic strategies and for evaluating chemoprevention strategies in HCC.

Topics: Animals; Animals, Genetically Modified; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; DNA Primers; Fatty Liver; Hepacivirus; Liver; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Microscopy, Confocal; Reverse Transcriptase Polymerase Chain Reaction; Thioacetamide; Viral Core Proteins; Zebrafish

Thioacetamide (TAA) has been used extensively in the development of animal models of acute liver injury. Frequently, TAA is administered intraperitoneally to induce liver damage under anaesthesia. However, it is rarely administered by intravenous injection in conscious rats. The experiments in this study were designed to induce acute liver damage by single intravenous injection of TAA (0, 70 and 280 mg/kg) in unrestrained rats. Biochemical parameters and cytokines measured during the 60-h period following TAA administration, included white blood cells (WBC), haemoglobulin (Hb), platelet, aspartate transferase (GOT), alanine transferase (GPT), total bilirubin (TBIL), direct bilirubin (DBI), albumin, ammonia (NH3), r-glutamyl transpeptidase (r-GT), tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Rats were sacrificed by decapitation 60 h after TAA administration and livers were removed immediately for pathology and immunohistochemical (IHC) examination. Another group of rats were sacrificed by decapitation 1, 6 and 24 h after TAA administration and livers were removed immediately for time course change of pathology and IHC examination. TAA significantly increased blood WBC, GOT, GPT, TBIL, DBIL, NH3, r-GT, TNF-alpha and IL-6 levels but decreased the blood Hb, platelet and albumin level. The levels of histopathological damage in the liver after intravenous TAA administration were also increased with a dose-dependent trend and more increased at 60 h after TAA administration. The levels of inducible nitric oxide synthase (iNOS) and nuclear factor-kappaB (NF-kappaB) detected by IHC in the liver after intravenous TAA administration were also increased with a dose-dependent trend and more increased at 1 h after TAA administration. Single intravenous TAA administration without anaesthesia is a restorable animal model which may be used to investigate acute liver damage.

Topics: Acute Disease; Alanine Transaminase; Animals; Aspartate Aminotransferases; Bilirubin; Carcinogens; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; gamma-Glutamyltransferase; Immunohistochemistry; Injections, Intravenous; Interleukin-6; Leukocyte Count; Liver; Liver Diseases; Male; Models, Animal; NF-kappa B; Nitric Oxide Synthase Type II; Random Allocation; Rats; Rats, Inbred WKY; Thioacetamide; Time; Tumor Necrosis Factor-alpha

We evaluated the usefulness of serum type-I arginase (ARG) and ornithine carbamoyltransferase (OCT) in thioacetamide (TAA)-induced acute and chronic liver injury in rats.. In an acute injury model, we measured the time-courses of serum concentrations of ARG and OCT using ELISA, together with AST and ALT using biochemical enzymatic assays after a single administration of TAA (200 mg/kg, i.p.). In the chronic model, TAA was repeatedly administered (20 mg/kg/day, p.o.) for 16 weeks and serum concentrations of the enzymes were evaluated.. In the acute model, the concentrations of the enzymes were increased in a similar manner, peaking 24 h after the administration, and ARG showed the earliest and greatest increase among the enzymes tested. In the chronic model, the serum concentration of OCT was significantly increased only 1 week after oral treatment, while concentrations of the other enzymes were increased at 8 to 12 weeks. In the histological analysis, TAA treatment damaged hepatocytes in both the acute and chronic model.. These results clearly show the usefulness of ARG and OCT for the evaluation of acute and chronic liver injury, respectively.

Topics: Alanine Transaminase; Animals; Arginase; Aspartate Aminotransferases; Biomarkers; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Liver; Liver Diseases; Male; Ornithine Carbamoyltransferase; Rats; Rats, Wistar; Thioacetamide

Thioacetamide (TA) is bioactivated by CYP2E1 to TA sulfoxide (TASO), and to the highly reactive sulfdioxide (TASO(2)), which initiates hepatic necrosis by covalent binding. Previously, we have established that TA exhibits saturation toxicokinetics over a 12-fold dose range, which explains the lack of dose-response for bioactivation-based liver injury. In vivo and in vitro studies indicated that the second step (TASO-->TASO(2)) of TA bioactivation is less efficient than the first one (TA-->TASO). The objective of the present study was to specifically test the saturation of the second step of TA bioactivation by directly administering TASO, which obviates the contribution from first step, i.e. TA-->TASO. Male SD rats were injected with low (50mg/kg, ip), medium (100mg/kg) and high (LD(70), 200mg/kg) doses of TASO. Bioactivation-mediated liver injury that occurs in the initial time points (6 and 12h), estimated by plasma ALT, AST and liver histopathology over a time course, was not dose-proportional. Escalation of liver injury thereafter was dose dependent: low dose injury subsided; medium dose injury escalated upto 36h before declining; high dose injury escalated from 24h leading to 70% mortality. TASO was quantified in plasma by HPLC at various time points after administration of the three doses. With increasing dose (i.e., from 50 to 200mg/kg), area under the curve (AUC) and C(max) increased more than dose proportionately, indicating that TASO bioactivation exhibits saturable kinetics. Toxicokinetics and initiation of liver injury of TASO are similar to that of TA, although TASO-initiated injury occurs at lower doses. These findings indicate that bioactivation of TASO to its reactive metabolite is saturable in the rat as suggested by previous studies with TA.

Topics: Alanine Transaminase; Animals; Area Under Curve; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; DNA Replication; Dose-Response Relationship, Drug; Histocytochemistry; Liver; Male; Microsomes, Liver; Rats; Rats, Sprague-Dawley; Thioacetamide; Thymidine

The hexane extract of Phyllanthus maderaspatensis (200 and 100 mg/kg) showed significant hepatoprotection on carbon tetrachloride and thioacetamide induced liver damage in rats. The protective effect was evident from serum biochemical parameters and histopathological analysis. Rats treated with P. maderaspatensis remarkably prevented the elevation of serum AST, ALT and LDH and liver lipid peroxides in CCl(4) and thioacetamide treated rats. Hepatic glutathione levels significantly increased by the treatment with the extracts. Histopathological changes induced by CCl(4) and thioacetamide were also significantly reduced by the extract treatment. The activity of hexane extracts of P. maderaspatensis was comparable to that of silymarin, the reference hepatoprotective drug.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Female; L-Lactate Dehydrogenase; Male; Phyllanthus; Phytotherapy; Plant Extracts; Protective Agents; Rats; Rats, Wistar; Thioacetamide

Thioacetamide (TA) undergoes saturation toxicokinetics in ad libitum (AL) fed rats. Diet restriction (DR) protects rats from lethal dose of TA despite increased bioactivation-mediated liver injury via CYP2E1 induction. While a low dose (50 mg TA/kg) produces 6-fold higher initial injury, a 12-fold higher dose produces delayed and mere 2.5-fold higher injury. The primary objective was to determine if this less-than-expected increase in injury is due to saturation toxicokinetics. Rats on AL and DR for 21 days received either 50 or 600 mg TA/kg i.p. T(1/2) and AUCs for TA and TA-S-oxide were consistent with saturable kinetics. Covalent binding of (14)C-TA-derived-radiolabel to liver macromolecules after low dose was 2-fold higher in DR than AL rats. However, following lethal dose, no differences were found between AL and DR. This lack of dose-dependent response appears to be due to saturation of bioactivation at the higher dose. The second objective was to investigate the effect of phenobarbital pretreatment (PB) on TA-initiated injury following a sub-lethal dose (500 mg/kg). PB induced CYP2B1/2 approximately 350-fold, but did not increase covalent binding of (14)C-TA, TA-induced liver injury and mortality, suggesting that CYP2B1/2 has no major role in TA bioactivation. The third objective was to investigate the role of CYP2E1 using cyp2e1 knockout mice (KO). Injury was assessed over time (0-48 h) in wild type (WT) and KO mice after LD(100) dose (500 mg/kg) in WT. While WT mice exhibited robust injury which progressed to death, KO mice exhibited neither initiation nor progression of injury. These findings confirm that CYP2E1 is responsible for TA bioactivation.

Topics: Alanine Transaminase; Animals; Aryl Hydrocarbon Hydroxylases; Aspartate Aminotransferases; Biotransformation; Caloric Restriction; Carcinogens; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2B1; Cytochrome P-450 CYP2E1; DNA, Complementary; Half-Life; Kinetics; Male; Mice; Mice, Knockout; Microsomes, Liver; Phenobarbital; Rats; Rats, Sprague-Dawley; Steroid Hydroxylases; Sulfoxides; Thioacetamide

Liver injury initiated by non-lethal doses of CCl(4) and thioacetamide (TA) progresses to hepatic failure and death of type 2 diabetic (DB) rats due to failed advance of liver cells from G(0)/G(1) to S-phase and inhibited tissue repair. Objective of the present study was to investigate cellular signaling mechanisms of failed cell division in DB rats upon hepatotoxicant challenge. In CCl(4)-treated non-diabetic (non-DB) rats, increased IL-6 levels, sustained activation of extracellular regulated kinases 1/2 (ERK1/2) MAPK, and sustained phosphorylation of retinoblastoma protein (p-pRB) via cyclin D1/cyclin-dependent kinase (cdk) 4 and cyclin D1/cdk6 complexes stimulated G(0)/G(1) to S-phase transition of liver cells. In contrast to the non-DB rats, CCl(4) administration led to lower plasma IL-6, decreased ERK1/2 activation, lower cyclin D1, and cdk 4/6 expression resulting in decreased p-pRB and inhibition of liver cell division in the DB rats. Furthermore, higher TGFbeta1 expression and p21 activation may also contribute to decreased p-pRB in DB rats compared to non-DB rats. Similarly, after TA administration to DB rats, down-regulation of cyclin D1 and p-pRB leads to markedly decreased advance of liver cells from G(0)/G(1) to S-phase and tissue repair compared to the non-DB rats. Hepatic ATP levels did not differ between the DB and non-DB rats obviating its role in failed tissue repair in the DB rats. In conclusion, decreased p-pRB may contribute to blocked advance of cells from G(0)/G(1) to S-phase and failed cell division in DB rats exposed to CCl(4) or TA, leading to progression of liver injury and hepatic failure.

Topics: Adenosine Triphosphate; Animals; Carbon Tetrachloride Poisoning; Cell Cycle; Chemical and Drug Induced Liver Injury; Cyclin D1; Cyclin-Dependent Kinases; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Immunoblotting; Interleukin-6; Liver Diseases; Male; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Rats; Rats, Sprague-Dawley; Retinoblastoma Protein; Thioacetamide; Transforming Growth Factor beta1

The ratio of ornithine carbamoyltransferase (OCT) to alanine aminotransferase (ALT) or glutamate dehydrogenase (GDH) in serum has been suggested as an indicator for the diagnosis of hepatocellular carcinoma and alcoholic liver disease, respectively. However, the mechanisms responsible for the increase in these ratios are still unclear.. Wistar rats were pretreated with lipopolysaccharide (LPS) or gadolinium chloride (GD) before being administered with thioacetamide (TAA, 200 mg/kg, ip). Serum OCT and ALT levels were compared with control values. Half-lives of the enzymes in circulation were evaluated after the intravenous injection of the purified enzymes into rats with or without the pretreatment.. The serum level of OCT at 24 h after the administration of TAA was significantly lower in the LPS-treated group, and not influenced by pretreatment with GD. The half-life of OCT was prolonged from 1.06+/-0.14 to 2.07+/-0.29 h (p<0.05) by the pretreatment with GD, but not influenced by the administration of LPS. No change was observed in the clearance of GDH or ALT among the pretreatments.. Leakage into and clearance from the circulation of OCT are influenced by whether Kupffer cells are activated or not. OCT alone or in combination with other markers may be a useful indicator for Kupffer cell activation as well as mitochondrial damage in hepatic cells.

Topics: Alanine Transaminase; Animals; Anti-Inflammatory Agents; Chemical and Drug Induced Liver Injury; Gadolinium; Glutamate Dehydrogenase; Hepatocytes; Kupffer Cells; Lipopolysaccharides; Liver; Liver Diseases; Male; Ornithine Carbamoyltransferase; Rats; Rats, Wistar; Thioacetamide

Eukaryotic cell cycle is regulated by signal transduction pathways mediated by complexes of cyclin dependent kinases (CDKs) and their partner cyclins, or by interaction with CDK inhibitors. Thioacetamide (TA) is a weak hepatocarcinogen causing several types of liver damage in a dose dependent manner and ultimately producing malignant transformation. We investigated alterations of expression of cell cycle regulators in the rat liver, involved in G1 entry and progression during TA administration.. We studied expression patterns of cyclin D1, CDK4, CDK6, p21(CIP1) and p16(INK4a) during daily intraperitoneal injection of low dose TA (50 mg/kg) till 7 day. We used western blot and immunohistochemistry for detection.. Expression of cyclin D1, CDK4, CDK6 and p21(CIP1) increased from 6 hour and peaked at 2, 3 day, then decreased next 2 days, and re-increased at 6 day. Cytoplasmo-nuclear translocation of cyclin D1 and p21(CIP1) was evident within 1 day and prominent at 2 and 7 day. Expression of p16(INK4a) increased immediately after TA treatment and remarkably increased from 3 day and progressed till 7 day, showing cytoplasmic location, suggestive of inactive form. Most of in situ immunoreactions occurred at the centrilobular hepatocytes. Concomitant nuclear translocation of p21(CIP1) and cyclin D1, different with p16(INK4a) suggests that p21(CIP1) might be a transporter for nuclear translocation rather than cell cycle inhibitor.. Daily administration of low dose TA makes cell cycle open and G1 progress, possibly due to cyclin D1, CDK4 and CDK 6, their transporter p21(CIP1), and inactive p16(INK4a), which occur at quiescent hepatocytes, not stem cells.

Topics: Animals; Cell Cycle Proteins; Chemical and Drug Induced Liver Injury; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase 6; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p21; G1 Phase; Immunohistochemistry; Liver; Liver Diseases; Male; Rats; Rats, Sprague-Dawley; Thioacetamide

In this study, we performed urinary metabolic fingerprinting using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) in the thioacetamide (TAA)-induced rat model of acute hepatic injury to search for useful biomarkers involved in the acute hepatic toxicity. TAA was intraperitonealy administered a single dose of 300 mg/kg, and urine sample and livers were collected on predose, and days 1, 3, 5, and 7 postdose (Days 1, 3, 5, and 7). Histopathologically, infiltration of macrophages occurred in the TAA-induced centrilobular injured area on Days 1 and 3, and the injured liver recovered on Days 5 and 7. On the scores plot of principal component analysis (PCA), the ion profiles of Days 1 and 3 were different from those of the predose, Days 5 and 7. The loading plot revealed that the metabolites causing PCA results were m/z 266.05390, 401.20737, and 429.23882. The ion at m/z 266.05390 was identified as a potassium ion adduct of deoxycytidine (dCyt). Because the appearance of urinary dCyt was corresponding to macrophage infiltration in the rat-injured liver, it was considered that the urinary dCyt might be released from infiltrated macrophages. dCty might be a biomarker for the acute hepatotoxicity in rats.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Biomarkers; Chemical and Drug Induced Liver Injury; Cyclotrons; Fourier Analysis; Liver; Macrophages; Male; Mass Spectrometry; Principal Component Analysis; Rats; Rats, Inbred F344; Thioacetamide

A previous study (Oliver, J.R., Mara, T.W., Cherian, M.G. 2005. Impaired hepatic regeneration in metallothionein-I/II knockout mice after partial hepatectomy. Exp. Biol. Med. 230, 61-67) has shown an impairment of liver regeneration following partial hepatectomy (PH) in metallothionein (MT)-I and MT-II gene knockout (MT-null) mice, thus suggesting a requirement for MT in cellular growth. The present study was undertaken to investigate whether MT may play a similar role in hepatic injury and regeneration after acute treatment with thioacetamide (TAA). Hepatotoxicity of TAA is caused by the generation of oxidative stress. TAA was injected ip to both wild-type (WT) and MT-null mice. Mice were killed at 6, 12, 24, 48, 60, and 72 h after injection of TAA (125 mg/kg) or 48 h after injection of saline (vehicle control), and different parameters of hepatic injury were measured. The levels of hepatic lipid peroxidation were increased at 12 h in both types of mice; however, lipid peroxidation was significantly less in WT mice than MT-null mice at 48 h after injection of TAA. Analysis of hepatic glutathione (GSH) levels after TAA injection showed depletion of GSH at 12 h in WT mice and at 6 h in MT-null mice; however, significantly more GSH was depleted early (6-24 h) in MT-null mice than WT mice. An increase in hepatic iron (Fe) levels was observed in both types of mice after injection of TAA, but Fe levels were significantly higher in MT-null mice than WT mice at 6-60 h. The levels of hepatic copper (Cu) and zinc (Zn) were significantly higher in WT mice than MT-null mice at 6-60 h for Cu, and at 24 h and 60 h for Zn, respectively. Histopathological examination showed hemorrhagic necrosis in the liver of both types of mice at 12-72 h, with hepatic injury being more prominent in MT-null mice than WT mice. The hepatic MT levels were increased in WT mice after injection of TAA, and were highest at 24-72 h. Immunohistochemical staining for MT in WT mice indicated the presence of MT in both nucleus and cytoplasm of hepatocytes at 24-72 h after TAA injection. Cell proliferation, as assessed by immunohistochemical staining for proliferating cell nuclear antigen, was detected mainly in the livers of WT mice at 48-72 h after TAA treatment. Hepatic proliferation index in MT-null mice was very low as compared to WT mice during liver regeneration after injection of TAA. These results show that the liver cells of MT-null mice with no functional MT are unable to regenerate afte

Topics: Acute Disease; Animals; Cell Proliferation; Chemical and Drug Induced Liver Injury; Glutathione; Iron; Lipid Peroxidation; Liver; Liver Regeneration; Metallothionein; Mice; Mice, Knockout; Necrosis; Thioacetamide

Previously, we reported high hepatotoxic sensitivity of type 2 diabetic (DB) rats to three dissimilar hepatotoxicants. Additional work revealed that a normally nonlethal dose of CCl4 was lethal in DB rats due to inhibited compensatory tissue repair. The present study was conducted to investigate the importance of compensatory tissue repair in determining the final outcome of hepatotoxicity in diabetes, using another structurally and mechanistically dissimilar hepatotoxicant, thioacetamide (TA), to initiate liver injury. A normally nonlethal dose of TA (300 mg/kg, ip), caused 100% mortality in DB rats. Time course studies (0 to 96 h) showed that in the non-DB rats, liver injury initiated by TA as assessed by plasma alanine or aspartate aminotransferase and hepatic necrosis progressed up to 48 h and regressed to normal at 96 h resulting in 100% survival. In the DB rats, liver injury rapidly progressed resulting in progressively deteriorating liver due to rapidly expanding injury, hepatic failure, and 100% mortality between 24 and 48 h post-TA treatment. Covalent binding of 14C-TA-derived radiolabel to liver tissue did not differ from that observed in the non-DB rats, indicating similar bioactivation-based initiation of hepatotoxicity. S-phase DNA synthesis measured by [3H]-thymidine incorporation, and advancement of cells through the cell division cycle measured by PCNA immunohistochemistry, were substantially inhibited in the DB rats compared to the non-DB rats challenged with TA. Thus, inhibited cell division and compromised tissue repair in the DB rats resulted in progressive expansion of liver injury culminating in mortality. In conclusion, it appears that similar to type 1 diabetes, type 2 diabetes also increases sensitivity to dissimilar hepatotoxicants due to inhibited compensatory tissue repair, suggesting that sensitivity to hepatotoxicity in diabetes occurs in the absence as well as presence of insulin.

Topics: Animals; Chemical and Drug Induced Liver Injury; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Susceptibility; Immunohistochemistry; Liver; Male; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Thioacetamide

The present study was carried out to study the effect of Butea monosperma, a known liver acting drug on the tumor promotion related events of carcinogenesis in rat liver. Thioacetamide (TAA) was used to induce tumor promotion response and oxidative stress and caused significant depletion in the detoxification and antioxidant enzyme armory with concomitant elevation in malondialdehyde (MDA) formation, hydrogen peroxide (H(2)O(2)) generation, ornithine decarboxylase (ODC) activity and unscheduled DNA synthesis. However, B. monosperma pretreatment at two different doses restored the levels of the above-said parameters (p < 0.001) in a dose-dependent manner. The alcoholic extract of B. monosperma used in the present study seems to offer dose-dependent protection and maintain the structural integrity of hepatic cells. This was evident from the significant reduction in TAA-induced serum GOT, GPT, Lactate dehydrogenase (LDH) and gamma-Glutamyl transpeptidase activity (GGT) activities (p < 0.001). These investigations validate the use of B. monosperma in liver disorders by Ayurvedic physicians. Overall results indicate that the methanolic extract of B. monosperma possesses hepatoprotective effects and also it might suppress the promotion stage via inhibition of oxidative stress and polyamine biosynthetic pathway.

Topics: Animals; Biomarkers; Butea; Carcinogens; Chalcone; Chalcones; Chemical and Drug Induced Liver Injury; DNA; Flavonoids; gamma-Glutamyltransferase; Glutathione; L-Lactate Dehydrogenase; Liver; Liver Diseases; Male; Medicine, Ayurvedic; Ornithine Decarboxylase; Oxidative Stress; Plant Extracts; Rats; Rats, Wistar; Thioacetamide; Transaminases

Steatohepatitis has recently been increasing as a cofactor influencing the progression of fibrosis, cirrhosis, adenoma and carcinoma in liver; however, the mechanisms by which it contributes to liver injury remain uncertain. We induced steatohepatitis in zebrafish embryos using thioacetamide (TAA). TUNEL assay revealed significant increasing of apoptosis in liver after 5 days post fertilization and the increasing of apoptosis was observed to be associated with the up-regulation of apoptotic genes such as, bad, bax, P-38a, caspase-3 and 8, and JNK-1. Histological sections by oil red O stain showed the accumulation of fatty droplets which causes the pushing of the nucleus towards one side. Up-regulation of steatosis markers such as, ACC, adiponectin, PTL, CEBP- alpha and beta, SREBP-1 was also observed. Furthermore, the elevation of glutathione peroxidase in TAA treated embryos indicated that TAA induces lipid peroxidation which leads to causes liver damage. Zebrafish has already been considered as a good human disease model and in this context; TAA-treated zebrafish may serve as a good animal model to study the molecular pathogenesis of steatohepatitis. Moreover, non-availability of specific drugs to prevent steatohepatitis, this animal model may serve as a powerful preclinical platform to study the therapeutic strategies and for evaluating chemoprevention strategies for this disease.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Embryo, Nonmammalian; Fat Necrosis; Hepatitis; Thioacetamide; Up-Regulation; Zebrafish

Exenatide is a 39 amino acid incretin mimetic for the treatment of type 2 diabetes, with glucoregulatory activity similar to glucagon-like peptide-1 (GLP-1). Exenatide is a poor substrate for the major route of GLP-1 degradation by dipeptidyl peptidase-IV, and displays enhanced pharmacokinetics and in vivo potency in rats relative to GLP-1. The kidney appears to be the major route of exenatide elimination in the rat. We further investigated the putative sites of exenatide degradation and excretion, and identified primary degradants. Plasma exenatide concentrations were elevated and sustained in renal-ligated rats, when compared to sham-operated controls. By contrast, exenatide elimination and degradation was not affected in rat models of hepatic dysfunction. In vitro, four primary cleavage sites after amino acids (AA)-15, -21, -22 and -34 were identified when exenatide was degraded by mouse kidney membranes. The primary cleavage sites of exenatide degradation by rat kidney membranes were after AA-14, -15, -21, and -22. In rabbit, monkey, and human, the primary cleavage sites were after AA-21 and -22. Exenatide was almost completely degraded into peptide fragments <3 AA by the kidney membranes of the species tested. The rates of exenatide degradation by rabbit, monkey and human kidney membranes in vitro were at least 15-fold slower than mouse and rat membranes. Exenatide (1-14), (1-15), (1-22), and (23-39) were not active as either agonists or antagonists to exenatide in vitro. Exenatide (15-39) and (16-39) had moderate-to-weak antagonist activity compared with the known antagonist, exenatide (9-39). In conclusion, the kidney appears to be the primary route of elimination and degradation of exenatide.

Topics: Animals; Chemical and Drug Induced Liver Injury; Chromatography, Liquid; Exenatide; Galactosamine; In Vitro Techniques; Kidney; Liver Cirrhosis; Male; Mass Spectrometry; Mice; Mice, Inbred Strains; Peptides; Rats; Rats, Sprague-Dawley; Thioacetamide; Venoms

As exposure to heterocyclic amines might increase the risk of liver cancer, we investigated the carcinogenic potential of MeIQx under conditions of liver damage caused by TAA. Male, 6-week-old F344 rats (n = 280) were divided into 14 groups; groups 1-7 received TAA (0.03% in drinking water) and groups 8-14 received water for the first 12 weeks. Thereafter, the animals received MeIQx at doses from 0, 0.001, 0.01, 0.1, 1, 10 to 100 p.p.m. (groups 1-7 and 8-14, respectively) in pellet basal diet for 16 weeks. All survivors were killed at week 28 for assessment of numbers and areas of GST-P positive foci, considered to be pre-neoplastic lesions of the liver. Values were increased significantly in all the groups receiving TAA-->MeIQx compared to MeIQx alone (P < 0.01). Numbers of GST-P positive foci were significantly increased in groups 7 and 14 (treated with 100 p.p.m. MeIQx) as compared to 0 p.p.m.-MeIQx (groups 1 and 8) (P < 0.01), along with areas in group 14 compared to group 8 (P < 0.01). However, with the maximum likelihood method, the data for numbers of GST-P positive foci (groups 1-7 and groups 8-14) fitted the hockey stick regression model, representing no differences from groups 1-5 and from groups 8-13, despite a linear dose-dependent increase of MeIQx-DNA adducts from 0.1 to 100 p.p.m. We conclude that there is a no effect level for MeIQx hepatocarcinogenicity, even on a background of TAA-induced liver damage.

Topics: 5-Methylcytosine; Animals; Carcinogens; Chemical and Drug Induced Liver Injury; Chromatography, High Pressure Liquid; DNA Adducts; Dose-Response Relationship, Drug; Glutathione Transferase; Immunohistochemistry; Liver Diseases; Liver Neoplasms, Experimental; Male; Quinoxalines; Rats; Thioacetamide

The hexane extract of oleo-gum-resin of Boswellia serrata (BSHE) was evaluated for its effect on liver injury induced by carbon tetrachloride, paracetamol or thioacetamide. The BSHE was given in two different doses (87.5 mg/kg p.o. and 175 mg/kg p.o.). Silymarin, a known hepatoprotective agent was used as standard. The lower dose of BSHE (87.5 mg/kg p.o.) significantly reduced the elevated levels of serum marker enzymes and prevented the increase in liver weight in all three models of liver injury, while the higher dose showed mild hepatoprotective activity. The hepatoprotective effect of lower dose of BSHE was supported by changes in histopathology. It was concluded that hexane extract of oleo-gum-resin of Boswellia serrata plant in lower doses possess hepatoprotective activity.

Topics: Acetaminophen; Animals; Anti-Inflammatory Agents; Boswellia; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Hexanes; Liver; Liver Diseases; Necrosis; Organ Size; Plant Extracts; Protective Agents; Rats; Rats, Wistar; Resins, Plant; Silymarin; Thioacetamide

Acute liver injury is associated with renal insufficiency, whose mechanism may be related to activation of the hepatorenal reflex. We previously showed that intrahepatic adenosine is involved in activation of the hepatorenal reflex to restrict urine production in both healthy rats and in rats with cirrhosis. The aim of the present study was to test the hypothesis that activation of intrahepatic adenosine receptors is involved in the pathogenesis of the renal insufficiency seen in acute liver injury. Acute liver injury was induced by intraperitoneal injection of thioacetamide (TAA, 500 mg/kg) in rats. The animals were instrumented 24 hours later to monitor systemic, hepatic, and renal circulation and urine production. Severe liver injury developed following TAA insult, which was associated with renal insufficiency, as demonstrated by decreased (approximately 25%) renal arterial blood flow, a lower (approximately 30%) glomerular filtration rate, and decreased urine production. Further, the increase in urine production following volume expansion challenge was inhibited. Intraportal, but not intravenous, administration of a nonselective adenosine receptor antagonist, 8-phenyltheophylline, improved urine production. To specify receptor subtype, the effects of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, an adenosine A(1) receptor antagonist) and 3,7-dimethyl-1-propargylxanthine (DMPX, an adenosine A(2) receptor antagonist) were compared. Intraportal but not intravenous administration of DPCPX greatly improved impaired renal function induced by acute liver injury, and this beneficial effect was blunted in rats with liver denervation. In contrast, neither intraportal nor intravenous administration of DMPX showed significant improvement in renal function. In conclusion, an activated hepatorenal reflex, triggered by intrahepatic adenosine A(1) receptors, contributed to the pathogenesis of the water and sodium retention associated with acute liver injury.

Topics: Adenosine A1 Receptor Antagonists; Adenosine A2 Receptor Antagonists; Animals; Chemical and Drug Induced Liver Injury; Denervation; Disease Models, Animal; Liver; Liver Diseases; Male; Rats; Rats, Sprague-Dawley; Receptor, Adenosine A1; Receptors, Adenosine A2; Renal Insufficiency; Sodium; Theobromine; Theophylline; Thioacetamide; Urine; Xanthines

Gingko biloba (GB) has antioxidant and platelet-activating factor (PAF) antagonistic effects. We investigated the protective effects of GB on thioacetamide (TAA)-induced fulminant hepatic failure in rats. Fulminant hepatic failure was induced in treatment groups by three intraperitoneal (ip) injections of TAA (350 mg/kg) at 24-hour intervals. Treatments with GB (100 mg/kg per day, orally) and N-acetylcysteine (20 mg/kg twice daily, sc) were initiated 48 hours prior to TAA administration. The liver was removed for histopathological examinations. Serum and liver thiobarbituric acid-reactive substance (TBARS) levels were measured for assessment of oxidative stress. Liver necrosis and inflammation scores and serum and liver TBARS levels were significantly higher in the TAA group compared to the control group (P < 0.001, < 0.001, 0.001, < 0.001, respectively). Liver necrosis and inflammation scores and liver TBARS levels were significantly lower in the GB group compared to the TAA group (P < 0.001, < 0.001 and 0.01, respectively). GB ameliorated hepatic damage in TAA-induced fulminant hepatic failure. This may be due to the free radical-scavenging effects of GB.

Topics: Acetylcysteine; Alanine Transaminase; Ammonia; Animals; Aspartate Aminotransferases; Bilirubin; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Drugs, Chinese Herbal; Free Radical Scavengers; Ginkgo biloba; Hepatic Encephalopathy; Liver; Male; Necrosis; Oxidative Stress; Platelet Aggregation Inhibitors; Rats; Rats, Wistar; Severity of Illness Index; Thioacetamide; Thiobarbituric Acid Reactive Substances

Rolipram is a specific type IV phosphodiesterase inhibitor that suppresses the activity of immune cells and the production of pro-inflammatory cytokines. In this study, we assessed the effect of rolipram on acute liver injury using thioacetamide (TAA)-induced liver injury in rats as a model.. Rats were treated with rolipram (0.5-5 mg/kg, intraperitoneally) or vehicle and injected 30 min later with TAA (100 mg/kg, subcutaneously). Serum transaminase concentrations and tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta) and growth related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1) levels were measured and livers were examined for microscopic changes. Dose-dependent protection against TAA liver injury was based on transaminase levels and inflammatory cytokine production, and was measured 9 h after TAA when the peak release of cytokines occurred.. Rolipram suppressed liver injury based on serum aspartate transaminase (AST), alanine transaminase (ALT) and histology and reduced TNF-alpha, IL-1beta and GRO/CINC-1 levels. Rolipram, at doses of 0.5-5 mg/kg, suppressed serum transaminase and TNF-alpha production in a dose-dependent manner, and these effects were significant at doses of 2.5 and 5 mg/kg.. In our rodent model of acute liver injury, rolipram clearly reduced liver damage and inhibited pro-inflammatory cytokine production. These results suggest that specific type IV phosphodiesterase inhibitors, such as rolipram, have potent hepatoprotective effects that are associated with suppressing inflammatory cytokine production.

Topics: Animals; Chemical and Drug Induced Liver Injury; Liver Diseases; Male; Phosphodiesterase Inhibitors; Rats; Rats, Sprague-Dawley; Rolipram; Thioacetamide

The effects of melatonin and dimethylsulfoxide (DMSO) on liver and brain oxidative stress, hepatic failure and blood urea nitrogen (BUN) level changes produced by a single dose of thioacetamide (TAA) in Wistar rats were studies. A dose of either melatonin (3 mg kg(-1)day(-1)) or DMSO (2 g kg(-1)day(-1)) was injected for 3 days before and for 2 days after the administration of TAA (150 mg kg(-1) i.p.). Blood samples were taken from the neck vascular in order to determine ammonium, BUN and liver enzymes. We estimated lipid peroxidation products, reduced glutathione (GSH) content and catalase activity in liver and brain homogenates. TAA caused significant increases in ammonium and in the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) enzymes, while it decreased BUN values. TAA also increased lipid peroxidation product levels, but reduced GSH content and catalase activity in the liver and brain. Both melatonin and DMSO, although melatonin more significantly, decreased the intensity of the changes produced by the administration of TAA alone. Furthermore, melatonin alone or combined with TAA increased the BUN levels and decreased the ammonia values compared with control animals. These results support the antioxidative and neuro-/hepato-protective action of melatonin and a lesser action of DMSO. Likewise, these data seem to support the hypothesis of an effect of melatonin on urea synthesis.

Topics: Alanine Transaminase; Ammonia; Animals; Blood Urea Nitrogen; Brain; Catalase; Chemical and Drug Induced Liver Injury; Dimethyl Sulfoxide; Glutathione; L-Lactate Dehydrogenase; Lipid Peroxidation; Liver; Liver Diseases; Male; Melatonin; Oxidative Stress; Protective Agents; Rats; Rats, Wistar; Thioacetamide

HESA-A, a marine compound, has been shown to exhibit antihepatic cancer, antitumor and anti-Parkinson effects. The hepatoprotective potential of HESA-A pretreatment at doses of 125 mg and 250 mg per day orally for a period of 40 days was evaluated against thioacetamide-induced liver damage in rabbits. Biochemical parameters such as serum glutamate oxaloacetate transaminase and lactate dehydrogenase in serum were estimated to assess liver function and lipid peroxidation products (malondialdehyde [MDA]) and the antierythrocyte lysis effect of plasma for measurement of antioxidant potential capacity. Data on the hepatic biochemical parameters revealed the hepatoprotective potential of HESA-A pretreatment against thioacetamide-induced hepatotoxicity in rabbits. There was an increase in total antioxidant and antierythrocyte lysis and a decrease in MDA in plasma after HESA-A treatment. These results strongly suggest that HESA-A has a protective action against preoperative damage to biomembranes.

Topics: Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Hemolysis; Lipid Peroxidation; Liver Function Tests; Male; Plant Preparations; Rabbits; Thioacetamide

Although hepatocyte transplantation is a promising therapy for acute liver failure in human, there is still a lack of animal models suffering from hepatic injury in which the benefits of hepatocyte transplantation could be evaluated solely, without the bias caused by immunosuppression. As a consequence, the aim of the study was first to develop reproducible models of partial hepatectomy and of thioacetamide (TA)- or Jo2-induced acute liver failure in nude mice. Chronic liver disease was also investigated by repeated injections of sublethal doses of thioacetamide. Survival rates, routine histologic observations, alanin aminotransferase sera content, Ki67, and caspase 3 immunodetection were investigated both after 40% partial hepatectomy and after toxic-induced damages. Liver injuries were more severe and/or precocious in nude mice than in Balb/c mice for a given treatment with a maximum of acute injury obtained 24 h after single toxic injection, and were found to be transitory and reversible within 10 days. Toxics induced apoptosis followed by necrosis, confirming recent published data. Onset of fibrosis leading to reproducible chronic cirrhosis in nude mice correlated with increasing number of Ki67-positive cells, indicating that high levels of cell proliferation occurred. Chronic cirrhosis progressively reversed to fibrosis when the treatment ceased. Preliminary results demonstrated that engrafted xenogeneic hepatocytes could be detected in the host liver by anti-MHC class I immunohistochemistry. Fractions enriched in 2n or 4n hepatocytes by cell sorting using a flow cytometer were equivalent to the unpurified fraction in terms of engraftment in control nude mice or in nude mice subjected to PH. However, in mice suffering from liver injury 24 h after Jo2 or TA treatment, the engraftment of 2n hepatocytes was about twice that of an unpurified hepatocyte population or of a population enriched in 4n hepatocytes.

Topics: Animals; Apoptosis; Chemical and Drug Induced Liver Injury; Chronic Disease; Disease Models, Animal; Graft Survival; Hepatectomy; Hepatocytes; Immunohistochemistry; Liver; Liver Diseases; Liver Failure, Acute; Liver Regeneration; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Rats; Rats, Sprague-Dawley; Thioacetamide

In a previous study, we identified Pistacia lentiscus was worthy for further laboratory evaluation because an aqueous extract of the plant suppressed iron-induced lipid peroxidation in rat liver homogenates without affecting mitochondrial respiration in cultured HepG2 and PC12 cells. The present study was undertaken to evaluate the efficacy of an aqueous extract prepared from the dried leaves of Pistacia lentiscus in a rat model of hepatic injury caused by the hepatotoxin, thioacetamide. We assessed the impact of daily dosing on biochemical and morphological indices and the extent of oxidative stress in the livers of healthy and thioacetamide-treated rats. In healthy rats, long-term administration of the extract induced hepatic fibrosis and an inflammatory response, mild cholestasis and depletion of reduced glutathione associated with an increase in its oxidized form. In thioacetamide-treated rats, long-term administration of extract aggravated the inflammatory and fibrotic and glutathione depleting responses without affecting the extent of lipid peroxidation. Although our previous in vitro study established that extracts prepared from the leaves of Pistacia lentiscus had antioxidant activity, this in vivo study establishes these extracts also contains hepatotoxins whose identity may be quite different from those compounds with antioxidant properties. The results of this study suggest complementing in vitro experiments with those involving animals are essential steps in establishing the safety of medicinal plants. Furthermore, these data confirm that complete reliance on data obtained using in vitro methodologies may lead to erroneous conclusions pertaining to the safety of phytopharmaceuticals.

Topics: Animals; Body Weight; Chemical and Drug Induced Liver Injury; Glutathione; Lipid Peroxidation; Liver; Liver Diseases; Male; Organ Size; Pistacia; Plant Extracts; Plant Leaves; Rats; Rats, Sprague-Dawley; Thioacetamide

To study the hepatoprotective effect of the aerial parts and the roots of G. scabra on cute liver injury models.. Acute liver injury models were induced by CCl4, TAA and D-GlanN in mice, and the levels of serum enzyme ALT, AST and AKP on acute liver injury mice with extracts of theaerial parts and the roots of G. scabra were determined.. Different dosages of theaerial part extract could significantly reduce the levels of serum enzyme ALT, AST and AKP (P < 0.05) on CCl4 and TAA model mice, but the serum enzymes reduction of D-GlanN model mice was not remarkably.. The methanolic extracts of the aerial parts and the roots of G. scabra both have certain hepatoprotective effects on acute liver injury models, and so the aerial parts of G. scabra can be used as the succedaneumm of G. scabra roots.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Aspartate Aminotransferases; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Drugs, Chinese Herbal; Female; Galactosamine; Gentiana; Male; Mice; Plant Components, Aerial; Plant Roots; Plants, Medicinal; Random Allocation; Thioacetamide

Free radical-mediated oxidative stress has been implicated in the pathogenesis of acute liver injury. The aim of our study was to investigate whether melatonin, a potent free radical scavenger could prevent fulminant hepatic failure in rats.. Liver damage was induced by two consecutive injections of thioacetamide (TAA, 300 mg/kg/i.p.) at 24 h intervals. Treatment with melatonin (3 mg/kg/daily, i.p) was initiated 24 h prior to TAA.. Twenty-four h after the second TAA injection, serum liver enzymes and blood ammonia were lower in rats treated with TAA+melatonin compared to TAA (P<0.001). Liver histology was significantly improved and the mortality in the melatonin-treated rats was decreased (P<0.001). The increased nuclear binding of nuclear factor kappa B in the livers of the TAA-treated rats, was inhibited by melatonin. The hepatic levels of thiobarbituric acid reactive substances, protein carbonyls and inducible nitric oxide synthase were lower in the TAA+melatonin-treated group (P<0.01), indicating decreased oxidative stress and inflammation.. In a rat model of TAA-induced fulminant hepatic failure, melatonin improves survival and reduces liver damage and oxidative stress. The results suggest a causative role of oxidative stress in TAA-induced hepatic damage and suggest that melatonin may be utilized to reduce liver injury associated with oxidative stress.

Topics: Ammonia; Animals; Chemical and Drug Induced Liver Injury; Free Radical Scavengers; Liver; Liver Diseases; Male; Melatonin; NF-kappa B; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Oxidative Stress; Rats; Rats, Wistar; Survival Rate; Thioacetamide; Thiobarbituric Acid Reactive Substances

The ethanolic extract of Trianthema portulacastrum L. (Aizoaceae) showed a significant dose dependent (100 mg, 200 mg/kg p.o. 10x) protective effect against paracetamol and thioacetamide induced hepatotoxicity in albino rats. The degree of protection was measured by using biochemical parameters like serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), bilirubin (BRN), and total protein (TP). The plant extract completely prevented the toxic effects of paracetamol (acetaminophen) and thioacetamide on the above serum parameters. A significant hepatoprotective activity of the ethanolic extracts of Trianthema portulacastrum L. was reported.

Topics: Acetaminophen; Aizoaceae; Animals; Chemical and Drug Induced Liver Injury; Female; Liver; Male; Phytotherapy; Plant Extracts; Plant Leaves; Protective Agents; Rats; Rats, Wistar; Thioacetamide

The effect of 1,8-cineole on cytochrome P450 (CYP) expression was investigated in male Sprague Dawley rats and female BALB/c mice. When rats were treated orally with 200, 400 and 800 mg/kg of 1,8-cineole for 3 consecutive days, the liver microsomal activities of benzyloxyresorufin- and pentoxyresorufin-omicron-dealkylases and erythromycin N-demethylase were dose-dependently induced. The Western immunoblotting analyses clearly indicated the induction of CYP 2B1/2 and CYP 3A1/2 proteins by 1,8-cineole. At the doses employed, 1,8-cineole did not cause toxicity, including hepatotoxicity. Subsequently, 1,8-cineole was applied to study the role of metabolic activation in thioacetamide-induced hepatotoxicity and/or immunotoxicity in animal models. To investigate a possible role of metabolic activation by CYP enzymes in thioacetamide-induced hepatotoxicity, rats were pre-treated with 800 mg/kg of 1 ,8-cineole for 3 days, followed by a single intraperitoneal treatment with 50 and 100 mg/kg of thioacetamide in saline. 24 h later, thioacetamide-induced hepatotoxicity was significantly potentiated by the pretreatment with 1,8-cineole. When female BALB/c mice were pretreated with 800 mg/kg of 1,8-cineole for 3 days, followed by a single intraperitoneal treatment with 100 mg/kg of thioacetamide, the antibody response to sheep red blood cells was significantly potentiated. In addition, the liver microsomal activities of CYP 2B enzymes were significantly induced by 1,8-cineole as in rats. Taken together, our results indicated that 1,8-cineole might be a useful CYP modulator in investigating the possible role of metabolic activation in chemical-induced hepatotoxicity and immunotoxicity.

Topics: Alanine Transaminase; Animals; Antibody Formation; Aspartate Aminotransferases; Blotting, Western; Body Weight; Carcinogens; Chemical and Drug Induced Liver Injury; Cyclohexanols; Drug Synergism; Erythrocytes; Eucalyptol; Immunosuppressive Agents; Male; Mice; Mice, Inbred BALB C; Microsomes, Liver; Mixed Function Oxygenases; Monoterpenes; Organ Size; Rats; Rats, Sprague-Dawley; Sheep; Thioacetamide

Heptatocyte growth factor (HGF) having a variety of biological activity was suggested as a protective agent against acute toxic hepatic injury or a potentially therapeutic agent. For the efficient in vivo application of this factor, we employed adenoviral-mediated HGF gene delivery system. In this study, we constructed E1-deleted recombinant adenovirus carrying cDNA of human HGF (Ad.hHGF) and elucidated that HGF was efficiently expressed in the liver of C57/BL mice. A mouse model of acute hepatic failure was induced by high dose (1000mg/kg) of thioacetamide (TA) administration. Mice infected with Ad.hHGF showed a dramatic resistance to TA-induced acute hepatic injury. Serum ALT was increased transiently and then the level was normalized in Ad.hHGF-infected mice with TA administration. Furthermore, the survival rate was remarkably enhanced in the mice infected with Ad.hHGF. In the histological examination, massive hepatic necrosis induced by TA was almost completely protected by HGF produced by Ad.hHGF. Our results indicate that a single dose of HGF-encoding adenoviral vector maintained liver function and prevented the progression of liver necrosis in a mouse model of acute hepatic failure.

Topics: Adenoviridae; Alanine Transaminase; Animals; Chemical and Drug Induced Liver Injury; Disease Models, Animal; DNA, Complementary; Genetic Therapy; Genetic Vectors; Hepatocyte Growth Factor; Liver; Liver Failure, Acute; Male; Mice; Mice, Inbred C57BL; Recombination, Genetic; Thioacetamide

Macrophages may play a role in fibrogenesis. The kinetics and distribution of different macrophage populations were investigated immunohistochemically in hepatic lesions following acute hepatocyte injury induced in F344 rats by a single injection of thioacetamide (TAA) (300 mg/kg body weight, intraperitoneally). Hepatocyte degeneration or necrosis induced by TAA occurred mainly in the perivenular areas of hepatic lobules as early as post-injection (PI) days 1 and 3; fibrotic lesion development began in the damaged areas on day 1, and peaked on day 5; thereafter (PI days 7 and 10), the fibrotic areas decreased and were replaced by regenerated hepatocytes on PI days 15 and 20, indicating a remodelling process. In this rat model, the number of macrophages reacting with ED1 antibody (specific for exudate macrophages), ED2 (recognizing cell membrane antigens of resident macrophages, including Kupffer cells) and OX6 (recognizing MHC class II antigens expressed in antigen-presenting macrophages and dendritic cells) began to increase on PI day 1, peaking on PI day 3. The numbers gradually decreased on PI days 5 and 7; however, the statistically significant increase was maintained in respect of ED1-positive cells up to PI day 20, whereas no significant increase in ED2- and OX6-positive cells remained from PI day 10 onwards. Interestingly, of the ED1-, ED2- and OX6-positive cells, the OX6-positive cells were the least numerous. ED1- and OX6-positive cells appeared exclusively in the injured perivenular areas, whereas ED2-positive cells were present mainly in the mid-zonal areas and in smaller numbers in the perivenular areas. These findings indicated differences in kinetics and distribution between macrophage populations appearing in hepatic fibrosis. In addition, RT-PCR revealed that mRNA expression of osteopontin, a factor for induction and maintenance of macrophages in inflammation, was markedly increased on PI days 5, 7 and 10, suggesting a role in the pathogenesis of hepatic fibrosis.

Topics: Animals; Antibodies, Monoclonal; Biomarkers; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Hepatocytes; Immunohistochemistry; Injections, Intraperitoneal; Liver Cirrhosis; Liver Regeneration; Macrophages; Male; Osteopontin; Rats; Rats, Inbred F344; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sialoglycoproteins; Thioacetamide; Transforming Growth Factor beta; Transforming Growth Factor beta1

Moderate dietary or caloric restriction (DR) modulates animal physiology in a beneficial fashion. Previously, we have reported an equitoxic dose experiment where liver injury in DR male Sprague-Dawley rats exposed to a low dose of thioacetamide (TA, 50 mg/kg) was similar to that observed in ad libitum fed (AL) rats exposed to a 12-fold higher dose (600 mg/kg). Paradoxically, the AL rats experienced 90% mortality while all of the DR rats, with the same amount of initial bioactivation-mediated liver injury, survived. The protection observed in the DR rats was due to efficient compensatory liver tissue repair, which was delayed and attenuated in the AL rats, leading to progression of liver injury. The objective of the present study was to investigate the molecular mechanisms of the enhanced tissue repair in the DR rats upon equitoxic challenge with TA. Promitogenic mechanisms and mediators such as proinflammatory cytokines (TNF-alpha and IL-6), growth factors (TGF-alpha and HGF), and inducible nitric oxide synthase (iNOS) were estimated over a time course after equitoxic challenge (50 mg/kg to DR vs. 600 mg/kg to AL rats). Except for TNF-alpha, all other molecules were expressed earlier and in greater amount in the DR rats. IL-6 was 10-fold greater and peaked 12 h earlier; HGF also peaked 12 h sooner in the DR rats, when it was 2.5-fold greater than the value in the AL rats. TGF-alpha expression in livers of DR rats increased after TA administration and peaked at 24 h. In the AL rats, it was lower and peaked at 36 h. Diet restriction alone induced iNOS 2-fold in the DR rats and remained elevated until 12 h after TA administration, then declined thereafter. The lower iNOS activity in the AL rats further decreased after TA injection. DR rats exhibited higher apoptosis after thioacetamide administration, which further increased the efficiency of tissue repair. Taken together, these data indicate that even though the liver injury is near equal in AL and DR rats, sluggish signal transduction leads to delayed liver regeneration, progression of liver injury, and death in the AL rats. The equitoxic dose experiment indicates that stimulation of tissue repair is independent of the extent of initial liver injury and is governed by physiology of diet restriction. DR stimulates promitogenic signaling leading to a quick and timely response upon liver injury, arrest of progressive injury on one hand, and recovery from injury on the other, paving the way for survival of the

Topics: Animals; Apoptosis; Caloric Restriction; Cell Division; Chemical and Drug Induced Liver Injury; Cytokines; Dose-Response Relationship, Drug; Food Deprivation; In Situ Nick-End Labeling; Liver; Liver Regeneration; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Rats; Rats, Sprague-Dawley; Signal Transduction; Survival Rate; Thioacetamide

The effect of Type 1 diabetes on the toxicity of thioacetamide was investigated in a murine model. In streptozotocin-induced diabetic C57BL6 mice a LD90 dose of thioacetamide (1000 mg/kg, ip in saline) caused only 10% mortality. Alanine aminotransferase activity revealed approximately 2.7-fold less liver injury in the diabetic (DB) mice compared to the non-DB controls, at 36 h after thioacetamide (TA) administration, which was confirmed via histopathological analysis. HPLC analyses revealed lower plasma t(1/2) of TA in the DB mice. Covalent binding of [(14)C]TA to liver tissue was lower in the DB mice, suggesting lower bioactivation of TA. Compensatory hepatic S-phase stimulation as assessed by [(3)H]thymidine incorporation occurred much earlier and was substantially higher in the DB mice compared to the non-DB cohorts. Morphometric analysis of cells in various phases of cell division assessed via immunohistochemical staining for proliferating cell nuclear antigen revealed more cells in G(1), S, G(2), and M phases in the DB mice, indicating robust tissue repair in concordance with the findings of [(3)H]thymidine pulse labeling studies. The importance of tissue repair in the resistance of DB mice was further investigated by blocking cell division in the DB mice by colchicine (1 mg/kg, ip) at 40 h after TA administration, well after the bioactivation of TA. Antimitotic action of colchicine, confirmed by decreased S-phase stimulation, led to progression of liver injury and increased mortality in DB mice. These findings suggest that lower bioactivation of TA and early onset of liver tissue repair are the pivotal underpinnings for the resistance of DB mice.

Topics: Animals; Antineoplastic Agents; Blood Glucose; Carcinogens; Chemical and Drug Induced Liver Injury; Colchicine; Diabetes Mellitus, Experimental; DNA; Enzymes; Immunohistochemistry; Liver Glycogen; Male; Mice; Mice, Inbred C57BL; Proliferating Cell Nuclear Antigen; Thioacetamide

Thioredoxin (Trx) is a small redox-active protein with antioxidant and antiapoptotic effects. Trx transgenic (Tg) mice are more resistant to cerebral infarction and survive longer than wild-type (WT) C57BL/6 mice. The aim of the present study was to investigate the protective role of Trx in acute hepatitis models. The expression of endogenous Trx was decreased in thioacetamide (TAA)-induced acute hepatitis. TAA (100 microg/g) was injected intraperitoneally in WT and Tg mice. Survival rate after TAA injection was higher in Tg mice than in WT mice. The level of oxidative stress was significantly less in Tg mice than in WT mice, as shown by the protein carbonylation assay and lipid peroxidation assay. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive cells were less in Tg mice than in WT mice, which was consistent with DNA laddering assay. Caspase-3 and caspase-9 activities and cytochrome c release were significantly inhibited in Tg mice compared with those in WT mice. In addition, lipopolysaccharide (LPS) plus d-galactosamine (GalN), or anti-Fas antibody (Jo2) were injected. Survival rate after LPS plus GalN injection was much higher in Tg mice than in WT mice. In contrast, there was no difference in survival rate after Jo2 injection between WT and Tg mice. In conclusion, transgene of Trx attenuated TAA- or LPS-induced acute lethal hepatitis. In addition to an antioxidant effect, Trx has the potential to protect acute liver injury via an antiapoptotic effect, which mainly inhibits mitochondria-mediated apoptosis signaling.

Topics: Acute Disease; Animals; Antibodies; Apoptosis; Chemical and Drug Induced Liver Injury; Down-Regulation; fas Receptor; Galactosamine; Humans; Lipopolysaccharides; Liver Failure; Male; Mice; Mice, Inbred C57BL; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Survival Rate; Thioacetamide; Thioredoxins

Kupffer cell function plays an important role in drug-induced liver injury. Thus, gadolinium chloride (GD), by selectively inactivating Kupffer cells, can alleviate drug-induced hepatotoxicity. The effect of GD was studied in reference to metallothionein and heat shock proteins expression in an in vivo model of liver necrosis induced by thioacetamide. Rats, pre-treated or not with GD (0.1 mmol/kg), were intraperitoneally injected with thioacetamide (6.6 mmol/kg), and samples of blood and liver were obtained at 0, 12, 24, 48, 72 and 96 hr. Parameters related to liver damage, Kupffer cell function, microsomal FAD monooxygenase activity, oxidative stress, and the expression of metallothionein and HSP70 were determined. GD significantly reduced serum myeloperoxidase activity and serum concentration of TNF alpha and IL-6, increased by thioacetamide. The extent of necrosis, the degree of oxidative stress and lipoperoxidation and microsomal FAD monooxygenase activity were significantly diminished by GD. The effect of GD induced noticeable changes in the expression of both metallothionein and HSP70, compared to those induced by thioacetamide. We conclude that GD pre-treatment reduces thioacetamide-induced liver injury and enhances the expression of metallothionein and HSP70. This effect, parallel to reduced levels of serum cytokines and myeloperoxidase activity, demonstrates that Kupffer cells are involved in thioacetamide-induced liver injury, the degree of contribution being approximately 50%.

Topics: Animals; Anti-Inflammatory Agents; Biotransformation; Chemical and Drug Induced Liver Injury; Drug Interactions; Gadolinium; Gene Expression; HSP70 Heat-Shock Proteins; Kupffer Cells; Male; Metallothionein; Microsomes, Liver; Mixed Function Oxygenases; NADP; Oxidative Stress; Rats; Rats, Wistar; Thioacetamide

Hepatoprotective activity of 3-bromo-6-(4-chlorophenyl)-4-methylthio-2H-pyran-2-one, an isostere of dimethyl ricinine, was evaluated in adult male albino rats intoxicated with carbon tetrachloride, paracetamol or thioacetamide. The test compound showed significant hepatoprotection at 6.0 mg kg(-1) body mass daily dose, given to the rats for seven consecutive days. The carbon tetrachloride, paracetamol and thioacetamide were given, respectively, on days 3, 5, and 7, on day 6 and on day 6 post treatment with the test compound. The protective effect was evident in a battery of serum and liver biochemical parameters related to hepatotoxicity.

Topics: Acetaminophen; Analgesics, Non-Narcotic; Animals; Carbon Tetrachloride Poisoning; Carcinogens; Chemical and Drug Induced Liver Injury; Cholesterol; DNA; Hydrocarbons, Halogenated; Liver; Liver Function Tests; Liver Glycogen; Male; Protein Biosynthesis; Pyrones; Rats; Rats, Sprague-Dawley; RNA; Thioacetamide

Intoxication of rats with thioacetamide (TAA) is a model system to investigate mechanisms involved in liver cell death and tissue reconstitution. Our study was undertaken to determine by immunohistochemistry the expression pattern of the cytoprotective chaperone proteins HSC70 and HSP25 and proliferation markers cyclin D1 and PCNA in livers of Wistar rats intraperitoneally injected with TAA at a single dose of 50 mg/kg. For each protein studied we observed distinct dynamic changes in appearance and localization in liver lobules. During 24-36 h after TAA injection the HSC70 cytoplasmic immunoreaction gradually disappeared from hepatocytes localized around central veins and a shift of immunostaining to cell nuclei took place. Then, 36-48 h after TAA injection the HSC70 cytoplasmic immunoreaction reappeared with the highest intensity in hepatocytes surrounding the areas of inflammatory cells. HSP25, undetectable in control hepatocytes began to appear at approximately 36 h after TAA injection and HSP25-immunopositive cells formed a characteristic ring around areas of inflammation. Of the proteins studied, the most rapid reaction to TAA was observed for cyclin D1. As early as 15 min after TAA administration cyclin D1-positive hepatocytes appeared in intermediate and periportal areas of liver lobules and a subsequent shift of staining to centrilobular hepatocytes took place at 36 and 48 h. There was no correlation of cyclin D1 localization either with PCNA-positive cells or mitotic cells. Our observations suggest that in TAA-treated livers HSP25 and HSC70 proteins can play an anti-inflammatory role, and the early and distinct cyclin D1 expression is not related to proliferation of hepatocytes.

Topics: Animals; Blotting, Northern; Blotting, Western; Chemical and Drug Induced Liver Injury; Cyclin D1; Disease Models, Animal; Heat-Shock Proteins; HSC70 Heat-Shock Proteins; HSP27 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Immunoenzyme Techniques; Injections, Intraperitoneal; Liver; Male; Neoplasm Proteins; Proliferating Cell Nuclear Antigen; Rats; Rats, Wistar; Thioacetamide; Time Factors

The influence of aging on the mechanisms of liver injury and regeneration was studied in a model of hepatotoxicity induced in 2-, 6-, 12-, 18- and 30-month-old rats by a sublethal dose of thioacetamide (500 mg/kg body weight), a soft nucleophilic and hepatotoxic compound metabolized by the hepatic microsomal FAD monooxygenase system. Samples-blood and hepatocytes-were obtained at 0, 12, 24, 48, 72 and 96 h following thioacetamide intoxication. Parameters of liver injury in serum (NADPH-isocitrate dehydrogenase (ICDH) activity) indicate that the severity of injury was significantly higher in the adult groups (6 and 12 months old) when compared either with the youngest (2 months old) or oldest (18 and 30 months old) groups. Parameters related to biotransformation, such as microsomal FAD monooxygenase, followed mainly the same pattern of age-dependent changes as those observed for injury. The profile of glutathione-S-transferase activity showed an initial induction parallel to liver injury and opposite to the levels of reduced glutathione and protein -SH groups. Enzyme activities and gene expression of the systems involved in the cell endogenous antioxidant defense, such as Mn- and Cu,Zn-superoxide dismutases (SOD), catalase and glutathione peroxidase (GPX) showed significant age-dependent changes that can be summarized as follows: an increase in all enzyme activities and gene expression and a decreased ability to restore the initial activities following 96 h of thioacetamide. We conclude, first, that the gene expression and activity of the enzymes involved in the intracellular antioxidant defense system increased with aging, which can be considered a consequence of the enhanced oxidative state of the cell (decreased in GSH level); and second, that the lower and delayed response in the aged groups significantly influenced the restoration towards normal of GSH and the antioxidant enzyme activities.

Topics: Age Factors; Aging; Animals; Antioxidants; Blotting, Northern; Catalase; Cells, Cultured; Chemical and Drug Induced Liver Injury; Enzyme Induction; Glutathione; Glutathione Peroxidase; Glutathione Transferase; Liver; Male; Oxygenases; Rats; Rats, Wistar; Superoxide Dismutase; Thioacetamide; Thiobarbituric Acid Reactive Substances

Thioacetamide (TAA) administration (three consecutive intraperitoneal injections of 400 mg/kg at 24-h interval) to rats resulted in hepatic injury as assessed by the measurement of serum transaminase activities and histopathological findings. This treatment caused an increase in the levels of malondialdehyde (MDA), diene conjugates (DCs) and glutathione (GSH) and the activity of superoxide dismutase SOD ), and a decrease in the levels of vitamins E and C and the activity of glutathione peroxidase (GSH-Px) in the liver of rats. Taurine administration (400 mg/kg, i.p., every 12 h and started 24 h prior to the first TAA injection) was found to decrease serum transaminase activities and hepatic lipid peroxidation without any significant change in hepatic antioxidant system. Histopathological findings also suggested that taurine has ameliorated effect on TAA-induced hepatic necrosis. These results indicate that taurine treatment, together with TAA administration, diminished the severity of the liver injury by decreasing oxidative stress due to its possible scavenger effect.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Female; Free Radicals; Liver; Rats; Rats, Wistar; Taurine; Thioacetamide

Previously we have shown that hepatotoxicity of thioacetamide (TA) was increased in streptozotocin (STZ)-induced diabetic (DB) rats due to combined effects of enhanced bioactivation-based liver injury of TA and compromised liver tissue repair response. We have also shown that TA is primarily bioactivated by hepatic CYP2E1. The present study was done to further investigate the importance of liver tissue repair in determining the final outcome of hepatotoxicity. STZ-induced DB rats were pretreated with a CYP2E1 inhibitor, diallyl sulfide (DAS), to decrease the bioactivation-based liver injury of TA. The treatments were as follows: DB/DAS/TA, DB/corn oil/TA, and DB/DAS/saline. Nondiabetic (non-DB) rats received the same treatments as controls. A dose of TA (300 mg/kg ip), which was nonlethal in non-DB rats, caused 92 and 90% mortality in DB/DAS/TA and DB/corn oil/TA groups, respectively. At various times (0--60 h) after treatment, liver injury was assessed by plasma alanine aminotransferase and histopathology. Cell proliferation was evaluated by [(3)H]thymidine incorporation and immunohistochemical staining of proliferating cell nuclear antigen (PCNA). In the DB/DAS/TA rats, DAS pretreatment markedly reduced the CYP2E1-dependent liver injury of TA compared to that in DB/corn oil/TA rats. However, subsequent hepatic DNA synthesis in both DB groups was inhibited approximately 50%. PCNA analysis showed a corresponding decrease in cell-cycle progression. This compromised tissue repair response in DB rats was insufficient to compensate for cell loss, resulting in progression of liver injury and culminating in high mortality in both DB groups. Furthermore, non-DB rats were pretreated with a CYP2E1 inducer, isoniazid, to increase the bioactivation-based TA liver injury equal to the liver injury observed in DB/DAS/TA rats. Despite equal injury up to 36 h following TA treatment, the tissue repair response in the non-DB rats was highly stimulated to compensate for liver injury and led to 70% survival in this group. These studies underscore the importance of adequate and timely tissue repair in compensating for liver injury and protecting from lethality.

Topics: Alanine Transaminase; Allyl Compounds; Animals; Cell Division; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2E1 Inhibitors; Diabetes Mellitus, Experimental; DNA; Enzyme Inhibitors; Immunohistochemistry; Liver; Liver Diseases; Male; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Sulfides; Thioacetamide

Earlier studies have shown highly exaggerated mechanism-based liver injury of thioacetamide (TA) in rats following moderate diet restriction (DR) and in diabetes. The objective of the present study was to investigate the mechanism of higher liver injury of TA in DR rats. Since both DR and diabetes induce CYP2E1, we hypothesized that hepatic CYP2E1 plays a major role in the bioactivation-based liver injury of TA. When male Sprague-Dawley rats (250-275 g) were maintained on diet restriction (DR, 35% of ad libitum fed rats, 21 days) the total hepatic microsomal cytochrome P450 (CYP450) was increased 2-fold along with a 4.6-fold increase in CYP2E1 protein, which corresponded with a 3-fold increase in CYP2E1 activity as measured by chlorzoxazone hydroxylation. To further test the involvement of CYP2E1, 24 and 18 h after pretreatment with pyridine (PYR) and isoniazid (INZ), specific inducers of CYP2E1, male Sprague-Dawley rats received a single administration of 50 mg of TA/kg (i.p.). TA liver injury was >2.5- and >3-fold higher at 24 h in PYR + TA and INZ + TA groups, respectively, compared with the rats receiving TA alone. Pyridine pretreatment resulted in significantly increased total CYP450 content accompanied by a 2.2-fold increase in CYP2E1 protein and 2-fold increase in enzyme activity concordant with increased liver injury of TA, suggesting mechanism-based bioactivation of TA by CYP2E1. Hepatic injury of TA in DR rats pretreated with diallyl sulfide (DAS), a well known irreversible in vivo inhibitor of CYP2E1, was significantly decreased (60%) at 24 h. CCl(4) (4 ml/kg i.p.), a known substrate of CYP2E1, caused lower liver injury and higher animal survival confirming inhibition of CYP2E1 by DAS pretreatment. The role of flavin-containing monooxygenase (FMO) in TA bioactivation implicated by previous in vitro studies, and consequent increased TA-induced liver injury in DR rats was tested in vivo with a relatively selective inhibitor of FMO, indole-3-carbinol, and then treated with 50 mg of TA/kg. FMO activity and alanine aminotransferase levels measured at different time points revealed that TA liver injury was not decreased although FMO activity was significantly decreased, suggesting that hepatic FMO is unlikely to bioactivate TA. These findings suggest induction of CYP2E1 as the primary mechanism of increased bioactivation-based liver injury of TA in DR rats.

Topics: Animals; Antioxidants; Blotting, Western; Body Weight; Carbon Tetrachloride; Carcinogens; Chemical and Drug Induced Liver Injury; Chromatography, High Pressure Liquid; Cytochrome P-450 CYP2E1; Diet; Indoles; Male; Microsomes, Liver; Monoamine Oxidase; Organ Size; Rats; Rats, Sprague-Dawley; Thioacetamide

Lines of evidence suggested a possible link between leptin and hepatic fibrosis; however, whether leptin modulates the fibrogenesis in the liver remains unclear. The purpose of this study, therefore, was to evaluate the effect of leptin on inflammatory and profibrogenic responses in the liver caused by hepatotoxic chemicals. Male C57Bl/6 mice were given carbon tetrachloride (CCl(4)) (0.1 microL/g body weight [BW], intraperitoneally [IP]) and/or recombinant murine leptin (1 microg/g BW, IP) simultaneously, and sacrificed up to 72 hours later. Further, some mice were given thioacetamide (TAA; 200 microg/g BW, IP) and leptin 3 times per week for 4 weeks to evaluate the effect of leptin on chronic fibrogenic responses. A simultaneous injection of leptin enhanced acute CCl(4)-induced necroinflammatory and subsequent fibrotic changes in the hepatic lobules. The steady-state messenger RNA (mRNA) levels of alpha1(I) procollagen and heat shock protein 47 (HSP47) in the liver were potentiated when leptin was injected together with CCl(4). Expression of alpha smooth muscle actin (alpha-SMA) in the liver after CCl(4) treatment was also augmented markedly in combination with leptin. Further, leptin increased transforming growth factor beta1 (TGF-beta1) mRNA in the liver 24 hours after acute CCl(4) about 4-fold higher than CCl(4) alone. Moreover, leptin enhanced hepatic fibrosis and induction of alpha1(I) procollagen mRNA caused by chronic TAA administration. Collectively, these findings indicated that leptin augments both inflammatory and profibrogenic responses in the liver caused by hepatotoxic chemicals. It is postulated that the increase in systemic leptin levels enhances up-regulation of TGF-beta1, leading to activation of stellate cells, thereby augmenting the fibrogenic response in the liver.

Topics: Actins; Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Endotoxins; Heat-Shock Proteins; HSP47 Heat-Shock Proteins; Leptin; Liver; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; Muscle, Smooth; Portal System; Procollagen; RNA, Messenger; Thioacetamide; Transaminases; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha

After 12 h of thioacetamide (500 mg/kg body weight) administration to rats, the activity of caspase-3-like protease in the liver increased significantly compared to that in the control group. In plasma, the activity of caspase-3 was barely detectable in the control rat, but had increased significantly after 24 h of drug administration along with a dramatic increase in GOT. These results indicate that thioacetamide causes apoptosis in the liver by activating caspase-3, which is released to plasma by successive necrosis. At 24 h, the concentration of liver lipid hydroperoxides, a mediator of radical reaction, was 2.2 times as high as that of control rats. After 12 and 24 h of thioacetamide administration, the liver concentrations of vitamins C and E decreased significantly. The decrease of antioxidants and formation of lipid hydroperoxides 24 h after thioacetamide administration support the view that extensive radical reactions occur in the liver during the necrotic process.

Topics: Animals; Apoptosis; Ascorbic Acid; Aspartate Aminotransferases; Caspase 3; Caspases; Chemical and Drug Induced Liver Injury; Enzyme Activation; Enzyme Induction; Free Radicals; Lipid Peroxidation; Liver; Male; Necrosis; Oxidation-Reduction; Oxidative Stress; Rats; Rats, Wistar; Thioacetamide; Thiobarbituric Acid Reactive Substances; Vitamin E

Metallothioneins (MT), a group of ubiquitous low molecular weight proteins, implicated primarily in metal ion detoxification, are known to be expressed during hepatocellular proliferation after partial hepatectomy in rats. In the present study, we investigated the expression of MT in a rat model of liver injury and regeneration, induced by intraperitoneal administration of thioacetamide (TAA). The animals were killed at 0, 12, 24, 36, 48, 60, 72, 84, 96, 108 and 120 hours after TAA administration. The rate of tritiated thymidine incorporation into hepatic DNA, the enzymatic activity of thymidine kinase, and the assessment of the mitotic index in hepatocytes were used as indices of liver regeneration. Liver MTs were detected immunohistochemically. TAA administration caused severe hepatic injury, followed by regeneration. MT expression became prominent in hepatocytes as early as 12 hours post-TAA administration. At 24 and 36 hours post-TAA administration intense nuclear and cytoplasmic staining of hepatocytes was found in the vicinity of necrotic areas. The maximal nuclear and cytoplasmic MT expression coincides with the peak of hepatocyte proliferative capacity, occurring at 48 and 60 hours post-TAA administration. MT expression correlated positively with the Zn content of liver tissue, but negatively with serum one, at the time of maximum hepatocyte proliferative capacity. This study suggests that MT participates in hepatocyte replication after toxin-induced liver injury.

Topics: Animals; Chemical and Drug Induced Liver Injury; DNA; Injections, Intraperitoneal; Liver; Liver Regeneration; Male; Metallothionein; Mitotic Index; Rats; Rats, Wistar; Thioacetamide; Thymidine; Thymidine Kinase; Zinc

Diabetes is known to potentiate thioacetamide (TA)-induced liver injury via enhanced bioactivation. Little attention has been given to the role of compensatory tissue repair on ultimate outcome of hepatic injury in diabetes. The objective of this study was to investigate the effect of diabetes on TA-induced liver injury and lethality and to investigate the underlying mechanisms. We hypothesized that hepatotoxicity of TA in diabetic rats would increase due to enhanced bioactivation-mediated liver injury and also due to compromised compensatory tissue repair, consequently making a nonlethal dose of TA lethal. On day 0, male Sprague-Dawley rats (250-300 g) were injected with streptozotocin (STZ, 60 mg/kg ip) to induce diabetes. On day 10 the STZ-induced diabetic rats and the nondiabetic rats received a single dose of TA (300 mg/kg ip). This normally nonlethal dose of TA caused 90% mortality in the STZ-induced diabetic rats. At various times (0-60 h) after TA administration, liver injury was assessed by plasma alanine aminotransferase (ALT), sorbitol dehydrogenase (SDH), and liver histopathology. Liver function was evaluated by plasma bilirubin. Cell proliferation and tissue repair were evaluated by [(3)H]thymidine ((3)H-T) incorporation and proliferating cell nuclear antigen (PCNA) assays. In the nondiabetic rat, liver necrosis peaked at 24 h and declined thereafter toward normal by 60 h. In the STZ-induced diabetic rat, however, liver necrosis was significantly increased from 12 h onward and progressed, culminating in liver failure and death. Liver tissue repair studies showed that, in the liver of nondiabetic rats, S-phase DNA synthesis was increased at 36 h and peaked at 48 h following TA administration. However, DNA synthesis was approximately 50% inhibited in the liver of diabetic rats. PCNA study showed a corresponding decrease of cell-cycle progression, indicating that the compensatory tissue repair was sluggish in the diabetic rats. Further investigation of tissue repair by employing equitoxic doses (300 mg TA/kg in the non-diabetic rats; 30 mg TA/kg in the diabetic rats) revealed that, despite equal injury up to 24 h following injection, the tissue repair response in the diabetic rats was much delayed. The compromised tissue repair prolonged liver injury in the diabetic rats. These studies suggest that the increased TA hepatotoxicity in the diabetic rat is due to combined effects of increased bioactivation-mediated liver injury of TA and compromised

Topics: Alanine Transaminase; Animals; Bilirubin; Chemical and Drug Induced Liver Injury; Diabetes Mellitus, Experimental; DNA; Drug Synergism; L-Iditol 2-Dehydrogenase; Liver; Liver Regeneration; Male; Necrosis; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Survival Rate; Thioacetamide; Thymidine; Time Factors

Thioacetamide (TA)-induced hepatotoxicity is potentiated in streptozotocin (STZ)-induced diabetic rats. The relative roles of CYP2E1 and FMO1 in the mechanism of TA-associated liver injury were investigated. In the STZ-induced diabetic rat, hepatic CYP2E1 protein concentration and p-nitrophenol hydroxylation were induced 8- and 5.6-fold, respectively. Pretreatment with the CYP2E1 inducer, isoniazid (INH, 250 mg/kg, i.p.) before TA (300 mg/kg, i.p.) administration significantly increased TA-associated liver injury as assessed by plasma alanine aminotransferase (ALT). Hepatic CYP2E1 expression and p-nitrophenol hydroxylation were induced 2.2- and 2. 5-fold in the INH-pretreated rat, respectively. Inhibition of CYP2E1 by diallyl sulfide (DAS, 200 mg/kg, p.o., two doses) before TA administration, decreased plasma ALT activity by 60% in the nondiabetic rat and by 75% in the diabetic rat. Abolition of microsomal p-nitrophenol hydroxylation and CCl(4)-induced liver injury confirmed that hepatic CYP2E1 was highly inhibited by DAS. Hepatic flavin-containing monooxygenase (FMO) form 1 expression and methimazole-dependent oxidation of thiocholine were induced 2.5- and 1.8-fold in the diabetic rat, respectively. Dietary administration of 0.25% indole-3-carbinol (I3C) for 10 days inhibited FMO1 expression and enzyme activity in both nondiabetic and diabetic rats. Paradoxically, TA-induced liver injury was increased in these I3C-pretreated rats. These findings indicate that hepatic CYP2E1 appears to be primarily involved in bioactivation of TA. In the STZ-induced diabetic rat, diabetes-induced CYP2E1 appears to be responsible for the potentiated liver injury; Even though hepatic FMO1 is induced in the diabetic rat, it is unlikely to mediate the potentiated TA hepatotoxicity.

Topics: Alanine Transaminase; Allyl Compounds; Animals; Biotransformation; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2E1; Cytochrome P-450 CYP2E1 Inhibitors; Diabetes Mellitus, Experimental; Enzyme Induction; Enzyme Inhibitors; Indoles; Isoniazid; Liver; Liver Diseases; Male; Oxygenases; Rats; Sulfides; Thioacetamide

R. tomentosus is a vegetal species closely related to the culinary rosemary (R. officinalis), a plant reported to contain antihepatotoxic agents. A dried ethanol extract of the aerial parts of Rosmarinus tomentosus (Lamiaceae) and its major fraction separated by column chromatography (fraction F19) were evaluated for antihepatotoxic activity in rats with acute liver damage induced by a single oral dose of thioacetamide. Silymarin was used as a reference antihepatotoxic substance. Pre-treatment with R. tomentosus ethanol extract, fraction F19 or silymarin significantly reduced the impact of thioacetamide toxicity on plasma protein and urea levels as well as on plasma aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and gamma-glutamyl transpeptidase activities compared with thioacetamide-treated animals (group T). Pre-treatment with R. tomentosus ethanol extract significantly reduced the impact of thioacetamide damage on alkaline phosphatase and gamma-glutamyl transpeptidase activities compared with group T. Silymarin administration significantly reduced alkaline phosphatase and gamma-glutamyl transpeptidase activities compared with group T. Fraction F19 administration reduced only alkaline phosphatase activity compared with group T. According to these data, R. tomentosus extract shows promising antihepatotoxic activity, suggesting the need to isolate the chemical principles responsible for this activity and to study this activity in a model of thioacetamide-induced cirrhosis.

Topics: Animals; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Female; Lamiaceae; Liver; Plant Extracts; Protective Agents; Random Allocation; Rats; Rats, Wistar; Thioacetamide

The objective of this paper was to evaluate serum glutathione S-transferasethe (GST) in thioacetimide (TAA)-induced hepatotoxicity in mice. The results showed that intraperitoneal injection of TAA (25-100 mg/kg) increased serum GST activity. The activity of GST was dose- and time-related to TAA. There was a good positive correlation between serum GST and serum alanine transaminase(ALT) activities. The content of reduced glutathione(GSH) and activities of GST, glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) were significantly decreased while serum GST activity induced by TAA was high. The results suggested that the reduced hepatic antioxidative function is one of the mechanism of TAA-induced hepatotoxicity, and serum GST activity is a sensitive and early marker in detecting TAA-induced hepatotoxicity.

Topics: Alanine Transaminase; Animals; Biomarkers; Chemical and Drug Induced Liver Injury; Glutathione Peroxidase; Glutathione Transferase; Male; Mice; Thioacetamide

Age-dependent changes related to liver injury and regeneration were studied in rats aged 2, 12, and 30 months in a time period of 96 hr following a sublethal dose of thioacetamide (6.6 mmoles/kg body wt). Serum aspartate aminotransferase activity increased earlier in young rats, but the severity of injury was higher in those aged 12 months when compared to young and to old. Microsomal hepatocyte FAD monooxygenase activity was induced earlier in 2-month-old rats following intoxication and the increase was significantly lower both in the youngest and in the oldest groups when compared to adults. As a parameter of hepatocellular postnecrotic regeneration, DNA synthesis (2C --> 4C) was evaluated. The population of hepatocytes in S phase peaked more sharply and earlier in young rat hepatocytes, and was 8 to 12 times higher than the initial in hepatocytes from 2- and 12-month-old rats, while the rise was only 3 times in the oldest group. At 96 hr of intoxication the restoration towards normal in all these parameters was complete in young, incomplete in adult, and slightly detected in the oldest. Serum proliferative activity, assayed on mouse NIH 3T3 fibroblast cultures, increased preceding the necrosis and this increase was higher in 2- and 12-month-old (171% and 224%, respectively), while in the oldest the increase was only 110%. This mitogenic activity decreased in all groups during necrosis, showing a second peak, nondetectable in rats aged 30 months, parallel to regeneration. Serum TNFalpha level was absent in untreated animals and increased markedly following intoxication, the highest values being recorded at 72 hr of intoxication in serum from rats aged 12 months (347 +/- 30 pg/ml) and the lowest at 30 months (4.1 +/- 0.3 pg/ml). The serum ability to induce nitric oxide synthase activity on peritoneal macrophages ex vivo showed significant time- and age-dependent changes in nitric oxide release: a decrease throughout necrosis and an increase during regeneration. We conclude that the main age-related changes in the sequenced process of liver injury and regeneration are the delayed response in the development of cell killing and regeneration and the decreased regenerative ability, which significantly delays the restoration of liver function.

Topics: 3T3 Cells; Aging; Animals; Aspartate Aminotransferases; Carcinogens; Cell Division; Chemical and Drug Induced Liver Injury; Glutathione; Liver; Liver Diseases; Liver Regeneration; Male; Mice; Necrosis; Nitric Oxide; Oxygenases; Rats; Rats, Wistar; Thioacetamide; Tumor Necrosis Factor-alpha

A possible role of metabolic activation by cytochrome P450 (P450) in thioacetamide-induced hepatotoxicity was investigated in male BALB/c mice. The mice were pretreated with the P450 inducer, beta-ionone, subcutaneously at 600 mg/kg, 72 and 48 h prior to an intraperitoneal administration of either 100 or 200 mg/kg of thioacetamide. The elevated activities of serum alanine aminotransferase and serum aspartate aminotransferase by thioacetamide were greatly potentiated by the pretreatment with beta-ionone. Moreover, the potentiation of thioacetamide-induced hepatotoxicity was also observed in the histopathological examination of livers. The hepatic necrosis by thioacetamide was potentiated when mice were pretreated with beta-ionone. In liver microsomes, the activities of P450 2B-specific pentoxyresorufin O-depentylase and benzyloxyresorufin O-debenzylase were significantly induced by the treatment with beta-ionone. Beta-ionone also induced other P450-associated monooxygenases. Because the pretreatment with beta-ionone was not hepatotoxic at the dose inducing P450s. our present results suggest that beta-ionone may be a useful model inducer of P450 enzyme(s) in studying toxic mechanism of certain chemicals which require metabolic activation by P450s in mice.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Carcinogens; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Drug Synergism; Enzyme Induction; Isoenzymes; Liver; Liver Function Tests; Male; Mice; Mice, Inbred BALB C; Microsomes, Liver; Norisoprenoids; Terpenes; Thioacetamide

We have previously reported that high-fat diets develop hepatic steatosis and, depending on the fat quality, affect serum lipid levels differently (J Nutr Sci Vitaminol, 1997, 43, 155-160). The aim of this work is to study the influence of high-fat diets (14% sunflower or olive oils) on serum lipids in a model of hepatic acute damage induced by thioacetamide, and their influence when dexamethasone is administered before thioacetamide injection. Serum lipids and hepatic collagen have been evaluated using biochemical methods, and the steatotic process by histological staining. The results showed that hepatic steatosis and fibrosis are developed either by high-fat diets or thioacetamide injection. Pretreatment with dexamethasone did not decrease the hepatic collagen content. Thioacetamide injection alone or pretreatment with dexamethasone produced increase in serum tryglicerides (TG), total cholesterol (TC) and LDL-C in both high-fat diet groups, and a HDL-C increase in the olive-oil group, even though the atherogenic indices (HDL/TC and HDL/TG) were different depending on the enriched diet. The administration of high-fat diets to study the influence of the fat quality on health and disease should be interpreted carefully due to the ability of the diets themselves to cause hepatic damage.

Topics: Animals; Chemical and Drug Induced Liver Injury; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Dexamethasone; Dietary Fats; Histocytochemistry; Laparotomy; Lipids; Liver; Liver Diseases; Male; Plant Oils; Rats; Rats, Wistar; Thioacetamide; Triglycerides

It has been shown recently that granulocyte colony-stimulating factor (G-CSF) accelerates and enhances the hepatocyte proliferative capacity of partially hepatectomized rats. In the present study, we investigated the effect of G-CSF administration in a rat model of liver injury and regeneration, induced by thioacetamide (TAA) injection. TAA (300 mg/kg body weight) was injected intraperitoneally in male Wistar rats, and this was followed by administration of either saline (group A) or G-CSF at a dose of 150 microg/kg body weight (group B), 24 hr later. The animals were killed at different time points after TAA treatment and the rate of tritiated thymidine incorporation into hepatic DNA, the activity of the enzyme thymidine kinase (EC 2.7.1.21) in the liver, and the assessment of the mitotic index of hepatocytes, were employed to estimate liver regeneration. The administration of TAA caused severe hepatic injury, recognized histopathologically and by the raised activities of the serum hepatic enzymes aspartate and alanine aminotransferases. The hepatic injury, which peaked 36 hr after TAA injection, was followed by a regenerative process of hepatocytes presenting peaks at time points of 48 and 60 hr (group A). The administration of G-CSF 24 hr after the injection of TAA (group B) caused a statistically significantly increase in the hepatocyte proliferation indices examined (P < 0.001), compared to those found in group A at the same time points. It was concluded that G-CSF administration enhanced the hepatocyte proliferative capacity in this model of liver injury induced by TAA administration.

Topics: Animals; Chemical and Drug Induced Liver Injury; Granulocyte Colony-Stimulating Factor; Liver; Liver Regeneration; Male; Rats; Rats, Wistar; Thioacetamide; Time Factors

N-acetylcysteine (NAC) is a glutathione precursor used to treat several clinical conditions where intracellular oxidant-antioxidant balance is disturbed, among which, acetaminophen induced hepatotoxicity may be counted. In this study, administering thioacetamide (TAA) as a hepatotoxic agent, a rat model of hepatotoxicity has been established, to investigate some of the immune mediated basic oxidant-antioxidant homeostatic mechanisms involved, and potential serum markers for follow-up of disease and treatment. To do this, four experimental groups receiving saline/saline, saline/NAC, saline/TAA and NAC/TAA as intraperitoneal injections, have been formed. Rat serum tumor necrosis factor-alpha (TNF-alpha), Interleukin1-beta (IL1-beta), malondialdehyde (MDA) as a measure of final oxidant damage and the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) have been assayed. Hepatocellular damage has been measured via the biochemical estimates ALT, AST and LDH as well as histopathological grading. It was found that both TNF-alpha and IL1-beta were significantly elevated in saline/TAA receivers (P<0.01) when compared to NAC/TAA receivers. Serum MDA was also increased in TAA receivers in addition to SOD (P<0.05) and GSH-Px (P<0.05). Serum nitrite levels have also been assayed to give an estimate of nitric oxide that is suggested as a counter-balancer of oxidant stress. NAC/saline receivers had the highest levels of nitrites in the serum (P<0.05). Our results indicate that part of the hepatocellular injury to rat liver, induced by TAA is mediated by oxidative stress caused by the action of cytokines imparted by the enzymatic SOD and GSH-Px and non-enzymatic gaseous nitric oxide mechanisms causing an alleviation on administration of NAC. In addition, TNF-alpha, IL1-beta, MDA, SOD, GSH-Px and nitrites are potential candidates of serum indicators for monitorization of pathophysiological stage of liver disease.

Topics: Acetylcysteine; Animals; Biomarkers; Chemical and Drug Induced Liver Injury; Cytotoxins; Disease Models, Animal; Free Radical Scavengers; Liver Diseases; Male; Oxidative Stress; Rats; Rats, Sprague-Dawley; Thioacetamide

Hepatic stimulator substance (HSS) is a known hepatic growth factor which appears to be organ-specific but species non-specific. We have recently shown that the administration of HSS enhanced hepatocyte proliferation occurring due to thioacetamide (TAA)-induced liver injury in rats (Theocharis SE, et al., Scand J Gastroenterol 1998; 33: 656-63). In the present study, we examined the activity of the endogenously produced HSS in the liver of TAA administered rats during injury and regeneration.. TAA at a dose of 300 mg/kg of body weight was injected intraperitoneally in male Wistar rats. The animals were sacrificed at 0, 12, 24, 36, 48, 60 and 72 h after TAA administration. The rate of tritiated thymidine incorporation into hepatic DNA, the enzymatic activity of liver thymidine kinase and the assessment of mitotic index in hepatocytes were used to estimate liver regeneration. HSS extract was obtained from the livers of TAA-treated rats, sacrificed at the above mentioned time points. This HSS extract was injected in 34% partially hepatectomized rats, to assess its activity. The ability of the injected HSS extract to increase hepatocellular proliferation over that normally occurring 24 h following 34% partial hepatectomy was used to express the activity of HSS by determining the above mentioned indices of liver regeneration.. The administration of TAA caused severe hepatic injury recognized histopathologically as well as by the increased activities of serum hepatic enzymes aspartate and alanine aminotrasferases. The hepatic injury, which peaked at 24 and 36 h post-TAA treatment (p<0.001), was followed by hepatocyte proliferation, presenting peaks at 48 and 60 h (p<0.001). The activity of the endogenously produced HSS from livers of TAA-treated rats increased at 36 h after TAA administration as well as being highly expressed at 48 and 60 h thus coinciding with the peak of hepatocyte proliferation. At other time points, HSS activity was decreased.. The observed variations of HSS activity in rat liver suggest active participation of this growth factor in hepatocyte replication which follows toxin-induced liver injury as a repair mechanism process.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; DNA; Growth Substances; Hepatectomy; Injections, Intraperitoneal; Intercellular Signaling Peptides and Proteins; Liver; Liver Regeneration; Male; Mitotic Index; Peptides; Rats; Rats, Wistar; Thioacetamide; Thymidine; Thymidine Kinase

Monomethyl fumarate, isolated for the first time from the methanolic extract of the whole plant of Fumaria indica, was characterised and screened for its antihepatotoxic activity in albino rats. The compound showed significant (P < 0.01) antihepatotoxic activity against thioacetamide in vitro, and against hepatotoxicities induced by carbon tetrachloride, paracetamol and rifampicin in vivo to an extent almost similar to that of silymarin, a known antihepatotoxic agent.

Topics: Acetaminophen; Alanine Transaminase; Alkaline Phosphatase; Animals; Aspartate Aminotransferases; Bilirubin; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Female; Fumarates; Galactosamine; Liver; Male; Maleates; Plant Extracts; Rats; Rats, Wistar; Rifampin; Silymarin; Thioacetamide

The protective effects of 1,3-dithia-2-thioxo-cyclopent-4-ene (DT827A),4-phenyl-1,3-dithia-2-thioxo-cyclopent- 4-ene (DT827B) and 4-(4-fluorophenyl)-1,3-dithia-2-thioxo-cyclopent-4-ene (DT827C) on liver injury induced by D-galactosamine plus carbon tetrachloride (D-GalN + CCl4) and that of DT827B on liver injury induced by thioacetamide were studied using male rats. Out of the three DT827 series of compounds, DT827B was more effective on liver injury induced by the combination exposure to D-GalN + CCl4 for 4 weeks, and accordingly the following two experiments were carried out using DT827B only. Twelve-week administration of DT827B at dose levels of 5, 10 and 20 mg/kg/day revealed a therapeutic effect against liver injury induced by D-GalN + CCl4 dose-dependently, and another twelve-week administration of DT827B at the same three dose levels also revealed a therapeutic effect against liver injury induced by thioacetamide dose-dependently. A hepatoprotective potential of DT827B was suggested under the conditions of these studies.

Topics: Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Galactosamine; Heterocyclic Compounds, 1-Ring; Liver Diseases; Male; Rats; Rats, Wistar; Thioacetamide; Thiones

Hepatic stimulator substance (HSS) is a known hepatic growth factor that appears to be organ-specific but species-nonspecific. In the present study we investigated the effect of HSS administration in a rat model of liver injury and regeneration induced by thioacetamide (TAA) injection.. TAA (300 mg/kg body weight) was injected intraperitoneally in male Wistar rats (group I). HSS (50 mg protein/kg body weight) was administered intraperitoneally either at 24 h (group II) or at 36 h (group III) after TAA treatment. The animals were killed at different time points after TAA injection, and the rate of tritiated thymidine incorporation into hepatic DNA, the activity of the enzyme thymidine kinase in liver, and the assessment of the mitotic index in hepatocytes were used to estimate liver regeneration.. The administration of TAA caused severe hepatic injury recognized histopathologically and by increased activities of the serum hepatic enzymes aspartate and alanine aminotransferases. The hepatic injury, which peaked at 24 h and 36 h after TAA injection, was followed by a regenerative process of hepatocytes which presented peaks after 48 h and 60 h (group I). The regenerative process of hepatocytes remained unaffected when HSS was administered 24 h after the injection of TAA (group II). In the case of HSS administration 36 h after the injection of TAA (group III) the examined indices of hepatocyte proliferation were statistically significantly increased at 48 h (P < 0.001), compared with those observed in group I.. The administration of HSS enhanced the hepatocyte proliferative capacity, induced by TAA treatment, depending on the time of its administration.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Carcinogens; Chemical and Drug Induced Liver Injury; Growth Substances; Intercellular Signaling Peptides and Proteins; Liver Regeneration; Male; Mitogens; Peptides; Rats; Rats, Wistar; Thioacetamide; Time Factors

A recent examination of retinae of patients who had died with symptoms of liver insufficiency (LI) including hepatic encephalopathy (HE) revealed morphological changes in retinal Müller glia similar to the astrocytic changes normally accompanying HE, and the term "hepatic retinopathy" (HR) was coined to define these changes. In the present study, the immunomorphology and ultrastructure of Müller cells were examined in rats in which LI with accompanying HE was induced with a hepatotoxin, thioacetamide (TAA). Light microscopically, retinae of rats with LI were characterized by swelling of the Muller cell cytoplasm. Immunostaining for glia-specific marker proteins in Müller cells from LI rats revealed a strongly enhanced expression of glial fibrillary acidic protein, and a considerable increase in glutamine synthetase immunoreactivity, as compared to control animals. Ultrastructurally, the Müller cells of LI rats showed swelling and vacuolization of cell processes. In particular, the endfeet contained many swollen mitochondria. By contrast, LI produced no morphologically demonstrable changes in retinal neurons and photoreceptor cells. Thus, the retinal changes induced by TAA in the rats strongly resembled those described in human HR, rendering the present rat model suitable for more detailed investigations of the pathomechanism(s) of HR.

Topics: Animals; Chemical and Drug Induced Liver Injury; Glial Fibrillary Acidic Protein; Glutathione Synthase; Humans; Immunohistochemistry; Microscopy, Electron; Neurons; Rats; Retina; Retinal Diseases; Thioacetamide

Although, diet restriction (DR) has been shown to substantially increase longevity while reducing or delaying the onset of age-related diseases, little is known about the mechanisms underlying the beneficial effects of DR on acute toxic outcomes. An earlier study (S. K. Ramaiah et al., 1998, Toxicol. Appl. Pharmacol. 150, 12-21) revealed that a 35% DR compared to ad libitum (AL) feeding leads to a substantial increase in liver injury of thioacetamide (TA) at a low dose (50 mg/kg, i.p.). Higher liver injury was accompanied by enhanced survival. A prompt and enhanced tissue repair response in DR rats at the low dose (sixfold higher liver injury) occurred, whereas at equitoxic doses (50 mg/kg in DR and 600 mg/kg in AL rats) tissue repair in AL rats was substantially diminished and delayed. The extent of liver injury did not appear to be closely related to the extent of stimulated tissue repair response. The purpose of the present study was to investigate the time course (0-120 h) of liver injury and liver tissue repair at the high dose (600 mg TA/kg, i.p., lethal in AL rats) in AL and DR rats. Male Sprague-Dawley rats (225-275 g) were 35% diet restricted compared to their AL cohorts for 21 days and on day 22 they received a single dose of TA (600 mg/kg, i.p.). Liver injury was assessed by plasma ALT and by histopathological examination of liver sections. Tissue repair was assessed by [3H]thymidine incorporation into hepatonuclear DNA and proliferating cell nuclear antigen (PCNA) immunohistochemistry during 0-120 h after TA injection. In AL-fed rats hepatic necrosis was evident at 12 h, peaked at 60 h, and persisted thereafter until mortality (3 to 6 days). Peak liver injury was approximately twofold higher in DR rats compared to that seen in AL rats. Hepatic necrosis was evident at 36 h, peaked at 48 h, persisted until 96 h, and returned to normal by 120 h. Light microscopy of liver sections revealed progression of hepatic injury in AL rats whereas injury regressed completely leading to recovery of DR rats by 120 h. Progression of injury led to 90% mortality in AL rats vs 30% mortality in DR group. In the surviving AL rats, S-phase DNA synthesis was evident at 60 h, peaked at 72 h, and declined to base level by 120 h, whereas in DR rats S-phase DNA synthesis was evident at 36 h and was consistently higher until 96 h reaching control levels by 120 h. PCNA studies showed a corresponding increase in cells in S and M phase in the AL and DR groups. DR resulted in

Topics: Animals; Carcinogens; Cell Division; Chemical and Drug Induced Liver Injury; Diet; Glycogen; Liver; Liver Diseases; Liver Function Tests; Liver Regeneration; Male; Rats; Rats, Sprague-Dawley; Thioacetamide

HD-03 is a polyherbal formulation containing plant drugs which are known for their hepatoprotective properties in the Ayurvedic system of medicine. In the present study, the formulation was evaluated for its protective effect against diverse hepatotoxic agents viz., paracetamol, thioacetamide and isoniazid. Treatment with HD-03 led to significant amelioration of toxin-induced changes in the biochemical parameters. Since the protective effect of HD-03 was observed in all three types of intoxication, which are different in their primary mechanism of inducing hepatotoxicity, a protective mode of action of HD-03, not specific to the hepatotoxin, is suggested.

Topics: Acetaminophen; Animals; Chemical and Drug Induced Liver Injury; Female; Isoniazid; Liver Function Tests; Male; Plant Extracts; Plants, Medicinal; Rats; Rats, Wistar; Thioacetamide

The roots of Boerhaavia diffusa L., commonly known as 'Punarnava', are used by a large number of tribes in India for the treatment of various hepatic disorders. In the present study the effect of seasons, thickness of roots and form of dose (either aqueous or powder) were studied for their hepatoprotective action to prove the claims made by the different tribes of India. The hepatoprotective activity of roots of different diameters collected in three seasons, rainy, summer and winter, was examined in thioacetamide intoxicated rats. The results showed that an aqueous extract (2 ml/kg) of roots of diameter 1-3 cm, collected in the month of May (Summer), exhibited marked protection of a majority of serum parameters, i.e. GOT, GPT, ACP and ALP, but not GLDH and bilirubin, thereby suggesting the proper size and time of collection of B. diffusa L. roots for the most desirable results. Further, the studies also proved that the aqueous form of drug (2 ml/kg) administration has more hepatoprotective activity than the powder form; this is probably due to the better absorbtion of the liquid form through the intestinal tract.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Aspartate Aminotransferases; Carcinogens; Chemical and Drug Induced Liver Injury; Ethnobotany; India; Male; Plant Extracts; Plant Roots; Plants, Medicinal; Powders; Rats; Thioacetamide

Heat shock proteins are ubiquitous intracellular proteins induced by various physiological stress-related events. A 72-kDa heat shock protein (HSP72) has been reported to be an endogenous cytoprotectant in variety of cells in vitro. In order to study the cytoprotective function of HSP72 in the liver, the effect of preinduction of HSP72 in rat liver by systemic hyperthermia on thioacetamide-induced hepatic injury was investigated in this study. Expression of HSP72 in the liver was investigated by immunoblot and densitometric analysis. Rats were injected with thioacetamide (100 mg/kg, subcutaneously) with or without preinduction of HSP72 by hyperthermia. Serum AST and ALT concentrations were measured before and after thioacetamide injection in both group. Histologic alteration of the liver was evaluated also. Systemic hyperthermia (42.5 degrees C, 20 min) significantly induced HSP72 in the liver. Thioacetamide-induced hepatic injury was clearly prevented by preinduction of HSP72 by hyperthermia. Prevention of hepatocyte damage was more clear in the area around central veins where HSP72 induction was apparent. Our findings might suggest that HSP72 has an important function in the liver with respect to cytoprotection. These results might be important for understanding the mechanism of "adaptive cytoprotection" in the liver mediated by the function of heat shock proteins as "molecular chaperons" as reported in vitro.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Heat-Shock Proteins; HSP72 Heat-Shock Proteins; Hyperthermia, Induced; Liver; Male; Premedication; Rats; Rats, Sprague-Dawley; Thioacetamide

Oral administration of two doses of corynoline, acetylcorynoline or protopine at 50 and 100 mg.kg-1 in an interval of 8 to 24 h before i.p. injection of CCl4, acetaminophen or thioacetamide significantly impeded the elevation of serum transaminase (SGPT) and liver damage in mice. The three compounds were found to inhibit CCl4-induced microsomal lipid peroxidation and CCl4 conversing to carbon monoxide in liver microsomes in vitro. Of these compounds, acetylcorynoline was shown to be more potent than corynoline and protopine. In addition, all the three compounds exhibited biphasic effects on the hepatic cytochrome P450, i.e. inhibition followed by induction, in mice.

Topics: Acetaminophen; Alanine Transaminase; Alkaloids; Animals; Benzophenanthridines; Berberine Alkaloids; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Liver; Male; Mice; Microsomes, Liver; Thioacetamide

In an earlier study we established that timely and adequate tissue repair response following the administration of a six-fold dose-range of thioacetamide (TA; 50, 150, and 300 mg/kg) prevented progression of injury and led to recovery and animal survival. Delayed and attenuated repair response after the 600 mg/kg TA dose resulted in a marked progression of injury and 100% lethality. The objective of the present study was to further scrutinize this concept in an experimental protocol in which we hypothesized that a selective ablation of the tissue repair response should lead to lethality from the nonlethal, moderately toxic doses of 150 and 300 mg/kg TA. In this study we investigated the effect of the antimitotic agent colchicine (CLC, 1 mg/kg) on the outcome of TA hepatotoxicity. Male Sprague-Dawley rats (175-225 g) were injected intraperitoneally (ip) with 150 and 300 mg/kg TA. We assessed liver injury by serum enzyme elevations and histopathology. Tissue regeneration response was measured by 3H-thymidine incorporation into hepatonuclear DNA and by proliferating cell nuclear antigen (PCNA) assay. S-Phase stimulation, as indicated by 3H-thymidine incorporation, was noted at 36 and 48 hr following the administration of 150 mg/kg TA, whereas with the 300 mg/kg TA S-phase stimulation was elicited at 48 hr following treatment. Therefore, two doses of CLC (30 hr and 42 hr, 1 mg/kg, ip) were administered to the 150 mg/kg treated group while a single dose of CLC (42 hr, 1 mg/kg, ip) was administered to the 300 mg/kg group. CLC treatment resulted in 100% lethality in both groups. Thus, CLC administration converted nonlethal doses into lethal doses. The 150 mg/kg TA dose was then chosen to further investigate the underlying mechanism. Rats treated with TA alone recovered from injury by 36-48 hr while CLC treatment resulted in a progression of injury as indicated by serum enzyme elevation and histopathology. Tissue repair, as evidenced by 3H-thymidine incorporation and PCNA studies explained this dichotomy. Antimitotic intervention with CLC resulted in a significantly diminished repair response leading to unrestrained progression of injury and lethality even from nonlethal doses. This model demonstrates the critical role of tissue repair response in determining the final outcome of toxicity.

Topics: Animals; Antineoplastic Agents; Chemical and Drug Induced Liver Injury; Colchicine; Liver Regeneration; Male; Rats; Rats, Sprague-Dawley; Thioacetamide

The dibasic amino acids arginine (ARG), ornithine (ORN) and lysine (LYS) are transported by a common saturable transporter (system gamma +) at the blood-brain barrier (BBB). In the present study we compared the brain uptake index (BUI) for radiolabelled ORN, ARG and LYS in control rats and in rats treated with thioacetamide (TAA) to induce hepatic encephalopathy (HE). Some animals received i.v. ornithine aspartate (OA), a drug structurally related to the gamma + substrates that ameliorates neurological symptoms following liver damage by improving detoxification of ammonia in peripheral tissues: the compound was administered either by continuous infusion for 6h at a concentration of 2 g/kg (final blood concentration ranging from 0.19-0.5 mM), or as a 15 sec. bolus together with the radiolabelled amino acids, at a concentration of 0.35 mM. TAA treatment resulted in a delayed and progressive increase of BUI for ORN, to 186% of control at 7d post-treatment and to 345% of control at 21d post-treatment, when despite sustained liver damage, HE symptoms were already absent. In contrast, the BUI for ARG decreased to 30% of control at 7d post-treatment and remained low (42% of control) at 21d post-treatment. A 6h infusion of OA to untreated rats resulted in a reduction of the BUI for ARG and ORN to 51% and 62% of the control levels, respectively. Reductions of a similar magnitude were noted with both amino acids following the 15 sec OA bolus, indicating direct interaction of OA with the transport site in both cases. OA administered by either route abolished the enhancement of BUI for ORN, but did not further inhibit the BUI for ARG in the TAA-treated animals. The results indicate that some as yet unspecified factors released from damaged liver either modify the structure or conformation of the gamma + transporter at the BBB from the normally ARG-preferring to the ORN-preferring state, or activate (induce) a different transporter specific for ORN which is normally latent.

Topics: Animals; Arginine; Blood-Brain Barrier; Brain; Chemical and Drug Induced Liver Injury; Dipeptides; Hepatic Encephalopathy; Infusions, Intravenous; Lysine; Male; Ornithine; Rats; Rats, Wistar; Thioacetamide

Thioacetamide (TA) is a well-known hepatotoxicant. It has been reported that an obligate intermediate of TA binds to proteins with the formation of acetylimidolysine derivatives that are responsible for TA-induced hepatotoxic effects. TA has also been reported to cause chemically induced cell death via both apoptosis and necrosis. The objective of this study was 2-fold: first, to investigate the effect of TA exposure on protein charge modifications in the rat liver and second, to study the role of these molecular correlates in the regulation of cell death. Male Sprague-Dawley rats (200-225 g, 7-8 weeks old) were divided into four major groups and treated intraperitoneally with a 12-fold dose range of TA (50, 150, 300, and 600 mg TA/kg) dissolved in water. Using whole liver extracts, alterations in the hepatic protein pattern following treatment with the 12-fold dose range of TA were studied using high-resolution, two-dimensional polyacrylamide gel electrophoresis and computerized image analysis. The results indicate that charge modification was clearly evident as early as 2 hr with the lowest dose of 50 mg TA/kg. At this dose and time endoplasmic reticulum proteins, calreticulin, grp78, and ER6O exhibited acidic charge variants. The effect of TA became more prominent with dose and time. Generally the elevation of charge modification indices (CMI) by TA appeared to reach a peak between 4 and 6 hr and then while CMI either leveled off or declined in the lower two doses of 50 and 150 mg TA/kg, it continued to remain elevated with the higher doses of 300 and 600 mg TA/kg. This dichotomy in the elevation of CMI is in close correspondence to the pattern of cell death observed with a similar dose range of TA, where lower doses (50 and 150 mg TA/kg) predominantly cause cell death via apoptosis while higher doses cause cell death via necrosis. Delayed charge modification was observed with the cytosolic hsc70s with the 300 and 600 mg TA/kg treatments, indicating that the reactive metabolite(s) slowly leak out into the cytosol from the endoplasmic reticulum. There were no alterations in the mitochondrial proteins hsp60 and grp75, suggesting that TA has no effect on the mitochondrion, its effects primarily being confined to the endoplasmic reticulum. The concept of looking at these proteins as biomarkers of tissue injury has validity. These changes may be indicators of bioactivation and adduct formation and also may be signaling events in the regulation of the mode o

Topics: Animals; Apoptosis; Carcinogens; Cell Division; Chemical and Drug Induced Liver Injury; Electrophoresis, Gel, Two-Dimensional; Heat-Shock Proteins; Image Processing, Computer-Assisted; Liver; Male; Molecular Chaperones; Protons; Rats; Rats, Sprague-Dawley; Thioacetamide

Acetaminophen (APAP) is a widely used analgesic and antipyretic drug that causes massive centrilobular hepatic necrosis at high doses, leading to death. The objectives of this study were to test our working hypothesis that preplaced cell division and hepatic tissue repair by prior thioacetamide (TA) administration provides protection against APAP-induced lethality and to investigate the underlying mechanism. Male Sprague-Dawley rats were treated with a low dose of TA (50 mg/kg, intraperitoneally [i.p.]) before challenge with a 90% lethal dose (1,800 mg/kg, i.p.) of APAP. This protocol resulted in a 100% protection against the lethal effect of APAP. Because TA caused a 23% decrease of hepatic microsomal cytochromes P-450, the possibility that TA protection may be caused by decreased bioactivation of APAP was examined. A 30% decrease in cytochromes P-450 induced by cobalt chloride failed to provide protection against APAP lethality. Time course of serum enzyme elevations (alanine aminotransferase, aspartate aminotransferase, and sorbitol dehydrogenase) indicated that actual infliction of liver injury by APAP peaked between 12 to 24 hours after the administration of APAP, whereas the ultimate outcome of that injury depended on the biological events thereafter. Although liver injury progressed in rats receiving only APAP, it regressed in rats pretreated with TA. Acetaminophen t1/2 was not altered in TA-treated rats, indicating that significant changes in APAP disposition and bioactivation are unlikely. Moreover, hepatic glutathione was decreased to a similar extent regardless of TA pretreatment, suggesting that decreased bioactivation of APAP is unlikely to be the mechanism underlying TA protection. [3H]Thymidine incorporation studies confirmed the expected stimulation of S-phase synthesis, and proliferating cell nuclear antigen studies showed a corresponding stimulation of cell division through accelerated cell cycle progression. Intervention with TA-induced cell division by colchicine antimitosis ended the TA protection in the absence of significant changes in the time course of serum enzyme elevations during the inflictive phase of APAP hepatotoxicity. These studies suggest that hepatocyte division and tissue repair induced by TA facilitate sustained hepatic tissue repair after subsequent APAP-induced liver injury, producing recovery from liver injury and protection against APAP lethality.

Topics: Acetaminophen; Animals; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Evaluation Studies as Topic; Liver Regeneration; Male; Microsomes, Liver; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Thioacetamide; Time Factors

It is likely that the hepatocellular metabolism of potent mediators of inflammation is impaired in chronic liver injury. Therefore, in this study the degradation of the leukotrienes LTC4, LTE4 and LTB4 was investigated in isolated liver parenchymal cells (LPC) from rats with thioacetamide-induced macronodular liver cirrhosis or after bile duct ligation. The degradation of LTE4 as well as the formation of N-acetyl-LTE4 was significantly delayed in LPC from macronodular cirrhotic rats but not in those from bile duct-ligated rats. LPC from macronodular cirrhotic rats eliminated LTC4 at the same rate as isolated hepatocytes from control animals. The rate of LTB4 degradation was significantly decreased by 35% in LPC from macronodular cirrhotic rats. Furthermore, the rate of LTB4 hydroxylation was significantly lower by 50% in microsomes isolated from hepatocytes of macronodular cirrhotic rats than in those from controls. In summary, one may conclude that the N-acetylation reaction of LTE4 and the hydroxylation reaction of LTB4 is impaired in LPC from rats with thioacetamide-induced macronodular cirrhosis.

Topics: Animals; Bile Ducts; Cells, Cultured; Chemical and Drug Induced Liver Injury; Female; Leukotrienes; Ligation; Liver; Liver Cirrhosis, Experimental; Rats; Rats, Inbred Strains; Thioacetamide

Seeds of Apium graveolens L. (Apiaceae) and Hygrophila auriculata (K. Schum.) Heine (Syn. Astercantha auriculata Nees, Acanthaceae) are used in Indian systems of medicine for the treatment of liver ailments. The antihepatotoxic effect of methanolic extracts of the seeds of these two plants was studied on rat liver damage induced by a single dose of paracetamol (3 g/kg p.o.) or thioacetamide (100 mg/kg, s.c.) by monitoring several liver function tests, viz. serum transaminases (SGOT and SGPT), alkaline phosphatase, sorbitol dehydrogenase, glutamate dehydrogenase and bilirubin in serum. Furthermore, hepatic tissues were processed for assay of triglycerides and histopathological alterations simultaneously. A significant hepatoprotective activity of the methanolic extract of the seeds of both the plants was reported.

Topics: Acetaminophen; Animals; Chemical and Drug Induced Liver Injury; Drug Interactions; Female; India; Liver; Liver Diseases; Liver Function Tests; Male; Medicine, Ayurvedic; Plant Extracts; Plants, Medicinal; Rats; Thioacetamide

Male Sprague-Dawley rats (n = 10/group) were fully protected from a lethal dose (600 mg/kg, i.p.) of thioacetamide by adding 8% (w/w) palmitic acid to the diet and L-carnitine (2 mg/ml) to drinking water for the previous 7 days. Supplements of palmitic acid or L-carnitine alone did not confer protection. Liver injury induced by thioacetamide peaked between 36 and 48 h in both control and supplemented rats. Liver damage regressed thereafter in supplemented rats but progressed in control rats. Immunohistochemical and histopathological observations confirmed biochemical indicators of liver damage. Thus, hepatic tissue repair after thioacetamide-induced tissue injury seems to be stimulated by supplements of fatty acids together with L-carnitine, a mitochondrial transfer agent. The extent to which nutritional supplements may aid in inducing the recovery of liver from injury caused by other hepatotoxic agents remains to be explored.

Topics: Analysis of Variance; Animals; Carnitine; Cell Division; Chemical and Drug Induced Liver Injury; Dietary Fats; Fatty Acids, Nonesterified; Liver Diseases; Male; Palmitic Acid; Palmitic Acids; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Thioacetamide

Heat shock protein (hsp), which changes both its concentration and localization in reaction to stresses such as heating, ischemia, etc., is thought to protect protein structure and act as a chaperone in intracellular transportation. We examined one of the hsps, hsp 70, in rat liver with necrosis and regeneration produced by thioacetamide (TAA). Hsp 70 was determined by immunoblotting and detected histologically by immunostaining, using a specific antibody. Generally, hsp 70 moves from the cytosol to the nucleus, where it concentrates 15 min after TAA injection. After 15 min, hsp 70 was not detected in the nuclei of hepatocytes around the central vein, where the hepatocytes later became necrotic. However, hsp 70 immunostaining was increasingly strong in the nuclei of hepatocytes around the portal area, which did not become necrotic. These findings show that, in acute necrosis, hsp 70 seems to correlate with nuclear protection or with the transportation of some protein from the cytosol to the nucleus. Hepatocytes probably neither survive nor regenerate without hsp 70 in their nuclei.

Topics: Animals; Chemical and Drug Induced Liver Injury; Heat-Shock Proteins; Immunoblotting; Liver; Liver Regeneration; Male; Necrosis; Rats; Rats, Wistar; Thioacetamide; Time Factors

Blumeatin (Blu, 5,3',5'-trihydroxy-7-methoxy-dihydro-flavone) was first isolated from Blumea balsamifera DC by Department of Chemistry, Sunyatsen University of China. Blu ip inhibited the increase of serum alanine aminotransferase (AAT) and liver triglyceride and increased serum triglyceride, beta-lipoprotein, and liver glycogen content in CCl4-intoxicated rats. Histological lesions of liver were less severe than those of hepatic injury control. Blu ip 0.65 and 3.25 mg.kg-1 inhibited the increase of serum AAT and hepatic TG in thioacetamide (TAA)-intoxicated mice. Blu ip shortened the pentobarbital sleeping time in CCl4-intoxicated mice. It suggested that Blu could protect liver against injury induced by CCl4 and TAA.

Topics: Alanine Transaminase; Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Drugs, Chinese Herbal; Female; Flavonoids; Liver; Male; Mice; Rats; Rats, Sprague-Dawley; Thioacetamide; Triglycerides

To determine whether lysosomal lipid composition is altered in hepatic necrosis, we studied this parameter in thioacetamide-induced necrosis and in its regenerating stage as well as in the recovery of thioacetamide-induced injury. Results showed that in liver necrosis there is an increase in the protein and phospholipid lysosomal contents. This effect may be related to an increased number of lysosomes. These organelles also suffered a decrease in cholesterol content. When liver necrosis was recovered either pharmacologically or spontaneously all three parameters recovered their normal values. These results suggest that lysosomes and their lipid composition play a role in progression of hepatic necrosis.

Topics: Acid Phosphatase; Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Cholesterol; Lipid Metabolism; Lysosomes; Male; Membranes; Necrosis; Rats; Rats, Wistar; S-Adenosylmethionine; Thioacetamide

Experiments have shown that the root of Polygonum multiflorum exhibits inhibitory effect on triglyceride (TG) accumulation in the liver of mice induced by CCl4, cortisone acetate and thioacetamide (TAA). Its processed products (I, II) were found to be effective in lowering the accumulated TG induced by cortisone acetate. The root of Polygonum multiflorum and its processed products also reduced the enlargement of liver by CCl4.

Topics: Animals; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Drugs, Chinese Herbal; Hot Temperature; Liver; Mice; Prednisone; Thioacetamide; Triglycerides

In order to determine whether acute toxic hepatitis in the rat is associated with an accumulation of methionine enkephalin in plasma and increased blood-to-brain transfer of methionine enkephalin, immunoreactive methionine enkephalin levels were determined by radioimmunoassay in plasma, cerebrospinal fluid and whole brain samples from rats with thioacetamide induced acute toxic hepatitis. Thioacetamide treatment was associated with an 8.7-fold increase in plasma immunoreactive methionine enkephalin levels (P less than or equal to 0.005) 24 h after treatment. However, this marked elevation in plasma immunoreactive methionine enkephalin levels was not associated with an increase in whole brain or cerebrospinal fluid immunoreactive methionine enkephalin levels. These data suggest that increased plasma-to-brain transfer of methionine enkephalin does not occur in this model of acute toxic hepatitis.

Topics: Acute Disease; Animals; Brain; Chemical and Drug Induced Liver Injury; Enkephalin, Methionine; Liver; Male; Rats; Rats, Sprague-Dawley; Thioacetamide

5-Fluoromethylornithine (5FMOrn) is a selective inactivator of ornithine aminotransferase. Its administration causes a dramatic increase of ornithine concentrations in all tissues. Treatment of mice with 20 mg.kg-1 5FMOrn shortly before or after a lethal dose (600 mg.kg-1, intraperitoneally) of thioacetamide (TAA), followed by a second dose 24 hr later, prevented death of 60% of the mice. Pathologic symptoms of TAA intoxication (liver haemorrhage, elevation of amino acids in blood and tissues, diminution of liver spermidine and spermine concentrations, elevation of the activity of liver enzymes in the plasma) were significantly ameliorated by the treatment. The liver protective action of 5FMOrn is related to the elevation of ornithine concentration, as appears from the fact that other, less selective inactivators of ornithine aminotransferase, also produced some protection against acute intoxication with TAA, but not a structurally related compound with no effect on this enzyme.

Topics: Amino Acids; Ammonia; Animals; Biogenic Polyamines; Chemical and Drug Induced Liver Injury; Hemorrhage; Liver Diseases; Male; Mice; Ornithine; Ornithine-Oxo-Acid Transaminase; Pilot Projects; Poisoning; Thioacetamide

A sequential study of the appearance of liver cell death after thioacetamide (TH) administration was performed in male Wistar rats. Within 3 hours of a single dose of TH, occurrence of cell death by apoptosis was evident around the centrilobular area. Light as well as electron microscopic examination demonstrated the presence of eosinophilic globules, often containing nuclear remnants (apoptotic bodies); they frequently were found within the cytoplasm of intact hepatocytes. The number of apoptotic bodies (ABs) was further enhanced at 6 hours, resulting in a 70-fold increase over the control values. Although necrosis or inflammation could not be observed at this time, as monitored by microscopic analysis as well as by determination of serum glutamate pyruvate transaminase levels, centrilobular necrosis accompanied by massive inflammatory reaction was evident at 12 hours and even more pronounced at 24 to 36 hours. Evidence of liver regeneration was found to occur at 48 hours, and the liver regained its normal architecture between 72 and 96 hours. Studies performed to analyze the activity of 'tissue' transglutaminase (tTG), a presumptive marker of apoptosis, showed that, 1 hour after treatment, TH caused a drastic dose-dependent inhibition of the enzyme activity. This early inhibition was followed by a rapid recovery in tTG activity that paralleled the induction of apoptosis in the liver. Treatment with cycloheximide (CH) 2 hours after TH partially inhibited the incidence of ABs at 6 hours (approximately 30% inhibition). The present study indicates that two different modes of cell death, apoptosis and necrosis, may be induced in a sequential fashion by a single dose of TH.

Topics: Alanine Transaminase; Animals; Cell Death; Chemical and Drug Induced Liver Injury; Cycloheximide; Dose-Response Relationship, Drug; Immunohistochemistry; Liver; Liver Regeneration; Male; Microscopy, Electron; Nafenopin; Necrosis; Rats; Rats, Inbred Strains; Thioacetamide; Time Factors; Transglutaminases

This study characterized the effects of liver damage produced by a variety of hepatotoxicants on several components of the sulfation pathway in rats. Specifically, the concentration of cosubstrate, adenosine 3'-phosphate 5'-phosphosulfate (PAPS), and the hepatic capacity for PAPS synthesis were measured in livers of rats treated with carbon tetrachloride (CCl4), 1,1-dichloroethylene (DCE), alpha-naphthylisothiocyanate (ANIT), aflatoxin B1 (ATX), allyl alcohol (AA), bromobenzene (BB), cadmium chloride (Cd), or thioacetamide (TA). Liver damage was assessed by measuring serum sorbitol dehydrogenase (SDH) and alanine aminotransferase (ALT) activities as well as by histopathological examination. Hepatic PAPS concentration was generally decreased as a result of treatment with hepatotoxicants (35-80% of control), although BB, AA, and ANIT were without effect. Maximal hepatic capacity for PAPS synthesis, determined as the activities of PAPS synthetic enzymes, ATP sulfurylase, and APS kinase, was selectively decreased by the hepatotoxicants. ATP sulfurylase activity was decreased by Cd and TA (55 and 62% of control, respectively), whereas APS kinase activity was decreased by Cd, TA, BB, and DCE (60-77% of control, respectively). In addition, phenol sulfotransferase (PST) activity was measured toward 1- and 2-naphthol in order to determine whether apparent changes in PST activity in damaged livers are substrate-dependent. Treatment with hepatotoxicants generally decreased 1-naphthol-directed PST activity but not PST activity directed toward 2-naphthol. In conclusion, (1) not all xenobiotic-induced liver injury results in decreased hepatic PAPS concentration, (2) some hepatotoxicants decrease PAPS concentration by a mechanism other than decreased cosubstrate synthesis, and (3) the effect of hepatotoxicants on PST activity is dependent upon the choice of substrate used in the enzymatic assay.

Topics: 1-Naphthylisothiocyanate; 1-Propanol; Aflatoxin B1; Alanine Transaminase; Animals; Arylsulfotransferase; Bromobenzenes; Cadmium; Cadmium Chloride; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Cytosol; Dichloroethylenes; L-Iditol 2-Dehydrogenase; Liver; Liver Diseases; Male; Phosphoadenosine Phosphosulfate; Propanols; Rats; Rats, Inbred Strains; Sulfates; Thioacetamide

Thioacetamide (100 mg/kg), when administered to normal rats, caused a significant increase in the activities of 5'-nucleotidase and gamma-glutamyl transpeptidase and a decrease in the activities of glucose 6-phosphatase and succinate dehydrogenase enzymes in the liver. DNA, RNA, and proteins were increased while the cytochrome P450 in the microsomal fraction and the glycogen content in the liver were decreased significantly. Elevations in the activities of GOT, GPT, and alkaline phosphatase and bilirubin content in serum were also observed. Picroliv, a standardised glycoside fraction of Picrorhiza kurroa, in doses of 12.5 and 25 mg/kg prevented most of the biochemical changes induced by thioacetamide in liver and serum. The hepatoprotective activity of Picroliv was comparable with that of silymarin, a known hepatoprotective agent obtained from seeds of Silybum marianum.

Topics: Animals; Chemical and Drug Induced Liver Injury; Cinnamates; Glycosides; Liver Diseases; Male; Rats; Rats, Inbred Strains; Silymarin; Thioacetamide; Vanillic Acid

The urinary excretion of taurine by rats after dosing with various hepatotoxins has been investigated by 1H NMR spectroscopy. After single hepatotoxic doses of hydrazine, carbon tetrachloride, 1-naphthylisothiocyanate, or thioacetamide there was biochemical and histopathological evidence of hepatic damage. Proton NMR spectroscopy of the urine collected for 24 h after dosing from these animals revealed a marked elevation in taurine (control 11.9 mumole/h/kg) after dosing with thioacetamide (42.2 mumole/h/kg), carbon tetrachloride (52.5 mumole/h/kg), 1-naphthyl-isothiocyanate (80.4 mumole/h/kg) and hydrazine (52.9 mumole/h/kg). After allyl alcohol administration there was no increase in taurine excretion (7.5 mumol/h/kg). The excretion of taurine after hydrazine administration was dose related. High resolution proton NMR spectroscopic analysis of urine also revealed resonances from several metabolites of hydrazine, an N-acetylcysteine conjugate of allyl alcohol, and acetamide as a metabolite of thioacetamide after dosing with the respective compounds. Changes in endogenous substances that may be related to the pathological events were also detected, such as a decrease in the excretion of 2-oxoglutarate and citrate after both hydrazine and carbon tetrachloride administration. The results confirm that proton NMR spectroscopic analysis of urine is a powerful analytical tool for the evaluation and study of toxic substances. Furthermore, measurement of urinary taurine may provide a non-invasive indicator of acute hepatic damage with certain classes of hepatotoxins.

Topics: 1-Naphthylisothiocyanate; Alanine Transaminase; Animals; Aspartate Aminotransferases; Bilirubin; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Hydrazines; Magnetic Resonance Spectroscopy; Male; Protons; Rats; Taurine; Thioacetamide

A method for simultaneous determination of cardiac output and regional blood flow distribution in a chronically instrumented, unrestrained rat preparation for different experimental conditions (i.e. conscious, free movement; general anesthesia) and in an experimental chronic liver injury model is described. The use of a modified radioactive microsphere reference sample method using 99mTc labelled HSA-microspheres provides valid measurements of cardiac output [255 +/- 21.6 ml/(min.kg b.wt.)] and of the determined blood flow rates of abdominal organs (with separate determination of arterial and portal-venous hepatic blood flow rates; the latter by means of arterial blood flow measurement of the gastrointestinal tract and the spleen), the myocard, the adrenals, the kidneys, and various brain regions. Furthermore, it is demonstrated that this measuring approach with chronical preparation can also advantageously be used in pharmacological or pathogenetical studies, especially because of the simple measuring equipment and the comparatively low costs that offer a broader application.

Topics: Abdomen; Anesthesia, General; Animals; Cardiac Output; Cerebrovascular Circulation; Chemical and Drug Induced Liver Injury; Chronic Disease; Female; Humans; Liver Diseases; Microspheres; Rats; Rats, Inbred Strains; Reference Values; Regional Blood Flow; Serum Albumin; Technetium; Thioacetamide

An imbalance of excitatory and inhibitory amino acid-ergic neurotransmission has been suggested to play a role in the pathogenesis of hepatic encephalopathy. For further evaluation of this hypothesis, several parameters of amino acid-ergic neurotransmission were studied in rats with acute liver failure induced by the administration of 300 mg per kg thioacetamide by gavage on two consecutive days. By appropriate supportive care, hypoglycemia, renal failure and hypothermia were avoided. Rats were monitored clinically and neurologically. Hepatic encephalopathy evolved in four distinct, easily recognizable stages. Light and electron microscopic examination of brains of rats with hepatic encephalopathy revealed only a slight swelling of nuclei of neurons and astrocytes without signs of neuronal degeneration or brain edema. In rats with hepatic encephalopathy, the concentrations of GABA, glutamate and taurine were decreased in the cerebral cortex, the hippocampus and the striatum, whereas those of aspartate and glycine were unchanged or increased. GABAA and benzodiazepine receptors were studied as parameters for the postsynaptic GABAA-benzodiazepine receptor complex, glutamic acid decarboxylase as parameter for presynaptic GABA-ergic neurons and stimulation of benzodiazepine binding by GABA as a parameter for a GABA-mediated postsynaptic event. None of these parameters was different in hepatic encephalopathy as compared to controls. Similarly, Ca++/Cl(-)-dependent and -independent glutamate receptors as parameters for glutamatergic neurons were unchanged in rats with hepatic encephalopathy. Thus, in rats with thioacetamide-induced liver failure and hepatic encephalopathy, changes of the concentrations of neurotransmitter amino acids occur in the brain. Other neurochemical parameters, however, failed to identify alterations of GABA-ergic or glutamatergic neurotransmission in hepatic encephalopathy.

Topics: Acetamides; Animals; Brain; Chemical and Drug Induced Liver Injury; gamma-Aminobutyric Acid; Glutamate Decarboxylase; Glutamates; Hepatic Encephalopathy; Kidney; Liver; Lung; Male; Neurotransmitter Agents; Rats; Rats, Inbred Strains; Receptors, GABA-A; Spleen; Thioacetamide

Kopsinine F is an indole alkaloid. The present studies show that prior oral administration of kopsinine F 150 mg/kg significantly protected mice from liver injuries induced by intraperitoneal injection of CCl4, thioacetamide and acetaminophen. The alkaloid also inhibited CCl4 induced lipid peroxidation (MDA formation) of liver microsomes and 14CCl4 covalent binding to lipids of liver microsomes in vitro. In addition, kopsinine F significanty induced hepatic microsomal cytochrome P-450 in mice. The results indicate that kopsinine F has hpatoeprotective activity in mice.

Topics: Acetaminophen; Alkaloids; Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Lipid Peroxidation; Male; Mice; Microsomes, Liver; Thioacetamide

Single 200 mg/Kg body weight i.p. injections of thioacetamide administered to litter mate male and female rats at 09.00, 13.00, 17.00 and 21.00 h caused body weight losses, elevated plasma glutamate pyruvate transaminase (GPT) levels, decreases in hepatic glycogen, zone 3-specific necrosis and leucocyte infiltration. All of these changes were more marked in males. The effects of thioacetamide on females were more severe at later injection times while no diurnal variations were apparent in males. Decreases in hepatic glycogen were most obvious in necrotic perivenous hepatocytes and correlated with increases in active glycogen phosphorylase which were probably caused by raised cytosolic calcium concentrations resulting from thioacetamide induced damage to cell membranes.

Topics: Acetamides; Alanine Transaminase; Animals; Chemical and Drug Induced Liver Injury; Circadian Rhythm; Female; Histocytochemistry; Liver; Liver Glycogen; Male; Rats; Rats, Inbred Strains; Sex Factors; Staining and Labeling; Thioacetamide

Male Wistar rats were given drinking water ad libitum with 0.075% thioacetamide (TAA) for 4 weeks. TAA treatment did not affect serum aminotransferase activities and total bilirubin content. The activities of 5'-nucleotidase, K+, Na+- and Mg2+-adenosine triphosphatases in liver plasma membrane preparations were strongly depressed, while that of gamma-glutamyl transferase was considerably increased. A decline in liver microsomal cytochrome P-450 and cytochrome b5 concentrations was also recorded. In contrast, the content of reduced glutathione in liver homogenate supernatant (9000 g) increased about 2-fold. As plasma membrane associated enzymes seem to be exclusively affected, the liver plasma membrane could be involved in the pathogenesis of the TAA-induced precirrhotic liver changes.

Topics: Acetamides; Administration, Oral; Animals; Cell Membrane; Chemical and Drug Induced Liver Injury; gamma-Glutamyltransferase; Liver Diseases; Male; Microsomes, Liver; Nucleotidases; Rats; Rats, Inbred Strains; Sodium-Potassium-Exchanging ATPase; Thioacetamide; Transaminases

Topics: Animals; Chemical and Drug Induced Liver Injury; Liver; Liver Diseases; Parenteral Nutrition; Protein Biosynthesis; Swine; Thioacetamide

Experimental liver injury was provoked experimentally in rats with intraperitoneal injections of thioacetamide. Traumatized rats received further intraperitoneal injections of Hepasor, a protoberberine alkaloid extract from Enantia chlorantha (Annonaceae) containing palmatine, columbamine and jatrorrhizine. The development of body weight was kept under continuous control. Biochemical assays of blood plasma, serum alanine transferase (S-ALT), serum alkaline phosphatase (S-AP), serum creatinine S-CREAT, serum hydroxyproline (S-OH-PROL) and serum calcium (S-Ca) were done and liver samples for histological processing were taken. The biochemical results obtained indicate Hepasor exerted a marked influence on the S-ALT activities and S-OH-PROL values in female rats, but more incidental one in male rats. Some reduction in S-AP activity and S-CREAT values, which was also dependent on sex, was also found. The histological findings in the liver sections of female rats show that Hepasor improves the blood flow and mitotic activity in thioacetamide-traumatized livers.

Topics: Acetamides; Animals; Berberine; Berberine Alkaloids; Chemical and Drug Induced Liver Injury; Drug Combinations; Female; Liver; Male; Plants; Rats; Rats, Inbred Strains; Thioacetamide

Topics: Alanine Transaminase; Animals; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Female; Fruit; Liver; Male; Medicine, Chinese Traditional; Mice; Thioacetamide; Triglycerides

A reproducible liver lesion was caused in 28 pigs by intermittent, intraperitoneal administration of thioacetamide. The morphological degree of the liver lesion was checked by histological investigations (material drawn from the liver by biopsy). During a 3-day infusion period a so-called liver solution (Aminofusin hepar) was given to one group of animals, a normal solution (Infesol) to a second group, and only an electrolyte infusion solution under oral nutrition ad libitum to a third one. The solutions were labelled with (15N) glycine. The amounts of total N, total 15N, 15N with single non-protein fractions, a number of enzymes of 15N incorporated into the liver protein were measured in urine, and the following points were established: 1. The catabolic situation of metabolism is eliminated both by the so-called normal solution and the specific amino acid solution. The two mixtures of L-amino acids thus have a nutritive effect. 2. The toxic liver lesion is an indication for parenteral nutrition. Oral nutrition alone is not sufficient. 3. The so-called liver solution influences the liver metabolism of the protracted liver lesion more than the so-called normal solution does, and considerably more than an electrolyte infusion solution under oral nutrition ad libitum.

Topics: Amino Acids; Amino Acids, Branched-Chain; Amino Acids, Essential; Animals; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Hepatic Encephalopathy; Liver Regeneration; Nitrogen; Parenteral Nutrition, Total; Swine; Thioacetamide

Liver injury was induced by one subcutaneous administration of thioacetamide (200 mg/kg b.wt.) and studied 24 and 48 hrs later. Levels of aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) increased after 24 and 48 hrs. The lysosomal enzymes beta-hexosaminidase (beta-NAG) and beta-glucuronidase (beta-GLU) increased significantly after 24 hrs, while the level of beta-GLU returned to normal after 48 hrs, but the activity of beta-NAG remained significantly high even after 48 hrs. Histopathological examination showed necrotic hepatocytes around the central vein with infiltration of macrophages, neutrophils and eosinophils. The plasma zinc level decreased after 24 hrs and returned to normal after 48 hrs. Liver zinc content increased simultaneously at 24 hrs, returning to normal after 48 hrs. No alterations of plasma copper were observed after 24 and 48 hrs. Copper content of the liver increased significantly after 24 and 48 hrs. The present study thus shows that one dose of thioacetamide results in profound liver injury and supplementation of zinc prior to and simultaneously with thioacetamide normalized plasma zinc, increased liver zinc content and reduced the increase of beta-NAG, but did not influence the histological changes.

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Copper; Liver; Male; Rats; Rats, Inbred Strains; Thioacetamide; Time Factors; Zinc

The effect of previous fasting on the liver morphological changes and microsomal cytochrome P-450 and b5 content was studied in thioacetamide-induced (100 mg/kg) rat liver necrosis. Starvation for 48 hours immediately before thioacetamide administration aggravates the dystrophic and necrotic processes, as revealed by histology, electron microscopic investigations and serum aminotransferase activity. The liver microsomal cytochrome P-450 concentration tended to decrease after thioacetamide challenge, with fasting resulting in a more significant loss of cytochrome P-450. Cytochrome b5 content, however, was found to increase in acute liver necrosis induced by thioacetamide.

Topics: Acetamides; Acute Disease; Animals; Chemical and Drug Induced Liver Injury; Liver; Liver Diseases; Male; Rats; Starvation; Thioacetamide

Experimental liver injury with different stages was provoked in rats with daily injected doses of thioacetamide (ThAA). The dose recommended for both male and female rats was 50 mg/kg body weight. The liver damages caused were acute, subacute, cirrhotic and necrotic, with a traumatization period of 2, 7, 14 and 21 days. The loss of body weight under traumatization, indicating osteopenia, was in the case of female rats during the first experimental week markedly accelerated, and in the two subsequent weeks apparently inhibited when compared to male rats. The loss of body weight of male rats revealed a progressive fall. Vital staining was made giving intraperitoneally 200 mg/kg body weight of alizarin red S (ARS). The staining intensity was improved in the acute stage for both calvaria and tibia and in the necrotic stage for tibia only. It was impaired in the subacute stage for calvaria and tibia and in the necrotic stage for calvaria only. Prolonged traumatization with ThAA causes pathological defects in the liver and kidneys. Furthermore, the epiphyseal cartilage of necrotic-stage rats was bright red without any ARS staining.

Topics: Animals; Anthraquinones; Body Weight; Bone and Bones; Bone Resorption; Calcium; Cartilage; Chemical and Drug Induced Liver Injury; Coloring Agents; Female; Kidney Diseases; Liver; Liver Diseases; Male; Rats; Sex Factors; Staining and Labeling; Thioacetamide

Sulphoxidation of cimetidine was investigated in male and female rats after pretreatment with the hepatotoxins allyl alcohol, dl-ethionine, thioacetamide and carbon tetrachloride. There was a marked sex difference in cimetidine sulphoxidation in response to the hepatotoxin pretreatment. All the hepatotoxins enhanced cimetidine sulphoxidation in the male rat (P less than 0.01). Carbon tetrachloride and thioacetamide inhibited cimetidine sulphoxidation in the female rat (P less than 0.01) but dl-ethionine and allyl alcohol had no effect on this metabolic pathway.

Topics: 1-Propanol; Animals; Bromobenzenes; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Cimetidine; Propanols; Rats; Rats, Inbred Strains; Sulfoxides; Thioacetamide

Experimental liver injury with different stages was induced to adult female test rats with daily injection of thioacetamide (ThAA). The doses administered intraperitoneally were 50 mg/kg body weight. In the liver sections progressive changes of damage, regeneration and fat substitution were noticed. Kidney sections revealed enhanced glomerular atrophy, particularly in the cortical tubules, provoked in the 3-week traumatization period. The influence of ThAA on female rat blood was assayed using standard biochemical methods. The analyses done were: the percentage of blood obtainable and the serum/blood ratio; the serum alanine transferase; serum alkaline phosphatase; serum creatinine; serum hydroxyproline and serum beta-glucuronidase activity in the acute, subacute, chronic and highly chronic stage of liver injury. The biochemical findings show continuously progressing damages when traumatization proceeds. In the 3-week test period the histological findings processed showed an increase in osteoclastic resorption in the alveolar bone around the occlusally stressed tooth simultaneously with a horizontal bone loss. Some indications of recovering incidents were seen, too. Only in the histological findings was no difference seen in the deterioration between both sexes, contrarily to the biochemical results also discussed in this study.

Topics: Alveolar Process; Animals; Bone Resorption; Chemical and Drug Induced Liver Injury; Female; Kidney; Liver Diseases; Rats; Rats, Inbred Strains; Stress, Mechanical; Thioacetamide

Carbon tetrachloride, chloroform, dimethylnitrosamine, thioacetamide or acetaminophen was each administered to rats in a single hepatotoxic dose. Nifedipine, verapamil or chlorpromazine was administered in association with the hepatotoxic agents to determine if calcium channel blocking agents would prevent an increase in liver cell calcium associated with hepatotoxicity and to determine if these agents would protect against the development of centrilobular necrosis. Following a latent period different for each toxic agent, a 4- to 18-fold increase in liver cell calcium content had occurred by 24 hr. The calcium increase and the centrilobular necrosis (mean histologic score) were correlated. A relatively high calcium to necrosis ratio was obtained with dimethylnitrosamine, thioacetamide and acetaminophen. A lesser calcium to necrosis ratio was obtained with chloroform and carbon tetrachloride, the two toxic agents that destroyed the intracellular calcium sequestration activity of the liver endoplasmic reticulum. Nifedipine or chlorpromazine, administered prior to and 7 hr after the toxic agent, completely prevented the centrilobular necrosis caused by thioacetamide, carbon tetrachloride and acetaminophen; almost completely prevented necrosis with dimethylnitrosamine; and provided partial protection against chloroform toxicity. Two doses of verapamil provided partial protection against necrosis when carbon tetrachloride was the toxic agent and provided almost complete protection with dimethylnitrosamine. A reduction in liver cell calcium was associated with the protective action of the three calcium channel blocking agents. These findings are compared with earlier studies of the protective effects of calcium channel blocking agents in cardiac ischemia.

Topics: Acetaminophen; Animals; Calcium; Calcium Channel Blockers; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Chloroform; Dimethylnitrosamine; Liver; Male; Microsomes, Liver; Necrosis; Rats; Rats, Inbred Strains; Thioacetamide

Topics: Animals; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Drug Evaluation, Preclinical; Galactosamine; Liver Diseases; Rabbits; Rats; Rats, Inbred Strains; Thioacetamide

Using mini-pigs with an indwelling vascular catheter, the pharmacokinetics of chloramphenicol were investigated in healthy and liver-damaged animals. The liver damage was induced by thioacetamide and its degree was estimated by measuring the level of bile acids in serum. Employing a two-compartment open model for analysing the time-dependent course of the chloramphenicol concentration in serum, it was shown that in liver-damaged animals the elimination half-time was almost doubled as a result of reduced total body clearance. The consequences of liver damage for withdrawal times and dosage schedules are discussed.

Topics: Animals; Chemical and Drug Induced Liver Injury; Chloramphenicol; Female; Half-Life; Liver Diseases; Male; Swine; Swine, Miniature; Thioacetamide

67Ga uptake of the liver began to elevate from the 1st day and reached a maximum at the 2nd day of treatment with thioacetamide (TIAA). Incorporation of 3H-thymidine into the liver DNA fraction was reached a maximum at the 1.5th day, and the value was 5.7 times of the control. The uronic acid content and 35S incorporation in the 1.2 M NaCl-soluble fraction which contained predominantly heparan sulfate (HS), were both peaked at the 2nd day. These patterns were in good agreement with that of 67Ga uptakes in the liver treated with TIAA. Pretreatment of aminoacetonitrile, an inhibitor of fibrosis, was effective in lowering the elevated uptake of 67Ga in TIAA-treated rat liver. Uptake of the 67Ga in the TIAA-treated liver was also inhibited when they were treated with cycloheximide, an inhibitor of protein synthesis. On the other hand no significant inhibition was observed in the cytosine arabinoside-treated-TIAA rats. These results suggest that HS may be involved in the 67Ga uptake in damaged liver, and that relation between 67Ga uptake and cell proliferation is secondary.

Topics: Acetamides; Animals; Cell Differentiation; Chemical and Drug Induced Liver Injury; Cycloheximide; Cytarabine; DNA; Gallium Radioisotopes; Heparitin Sulfate; Liver; Male; Rats; Thioacetamide; Thymidine

To study the relationship between lipid peroxidation and cellular damage we studied three compounds known to evoke lipid peroxidation (cumene hydroperoxide, CHP), hepatocellular injury (thioacetamide, TAA) or both (carbon tetrachloride, CCl4). Phenobarbital-induced male rats were treated with one of the three agents and lipid peroxidation was monitored via the measurement of exhaled ethane. Treatment with both, CCl4 and CHP resulted in an increased ethane expiration, whereas TAA did not. When liver-specific serum enzyme activities (GPT, SDH) were investigated 24 h later, however, hepatotoxicity was evident only in rats treated with either CCl4 or TAA. The ATP-dependent Ca2+-sequestration activity of microsomal membranes, suggested to be a final common pathway leading to cellular death, was studied in microsomes isolated from rats treated with either agent. 2 h after treatment with CCl4 or TAA a clear inhibition was seen which persisted after 24 h in the case of CCl4 only. CHP did not affect the Ca2- -pump activity. Thus, a clear correlation between cellular damage and lipid peroxidation cannot be expected in every case. An impairment of the microsomal calcium-pump, however, seems to be a crucial event which leads to hepatocellular injury.

Topics: Animals; Benzene Derivatives; Calcium; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Lipid Peroxides; Male; Microsomes, Liver; Rats; Rats, Inbred Strains; Thioacetamide; Time Factors

Plasma amino acids, serum enzymes, liver glutathione and the hepatic lipid peroxidation capacity of the rat were investigated in acute thioacetamide toxicity. These were examined in parallel with the earliest pathological changes shown by electron microscopy. Plasma arginine levels were significantly lowered 3 h after dosing thioacetamide and by 9 h were indistinguishable. This finding correlates with other workers demonstrating urea cycle damage in alcohol and carbon tetrachloride damaged rat liver. Depressed arginine plasma levels were detectable before any of the biochemical or pathological processes co-examined and as such may prove useful as a sensitive in vivo method for detection of acute liver damage.

Topics: Acetamides; Alanine Transaminase; Amino Acids; Animals; Arginine; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Liver; Liver Diseases; Male; Microscopy, Electron; Rats; Thioacetamide

As a result of traumata, cancer or chemical poisoning the level of acute-phase proteins released by the liver undergoes a significant change which can be measured by two-dimensional immunoelectrophoresis. To investigate whether inflammatory reactions following chemical poisoning, tissue necrosis or other treatments result in an uniform change of the plasma protein profile, we examined quantitatively the change in plasma protein profile in the following model situations: 1) alloxan-induced diabetes in rats, 2) thioacetamide-induced liver cirrhosis and 3) ixoten-induced blocking of DNA synthesis in rat liver. Even though the three agents used in the present study or their metabolites directly interacted with liver cells, they did not evoke a uniform change of the plasma protein profile.

Topics: Animals; Blood Proteins; Chemical and Drug Induced Liver Injury; Cyclophosphamide; Diabetes Mellitus, Experimental; Immunoelectrophoresis; Rats; Rats, Inbred Strains; Sarcoma, Yoshida; Thioacetamide

Liver damage was produced in male Wistar rats aged 15 weeks by daily oral administration of 40 mg/kg thioacetamide over a period of 24 weeks. All of the animals were weighed once a week. Furthermore, the duration of hexobarbital anaesthesia and the activities of the enzymes ASAT, ALAT, GIDH, LDH, LAP and alkaline phosphatase in the serum were determined in 6 experimental and 4 control animals after 3 d and 1, 2 and 4 weeks, and then at intervals of 4 weeks. For the purpose of comparison the same investigations were performed (under identical experimental conditions) both in rats fed normally and rats starved for 24 h to which a single dose of thioacetamide was applied. The histological study of the livers revealed destruction of the lobule architecture and profuse bile-duct proliferations after 12 weeks. Cirrhosis was observed after 16 weeks. The activities of ASAT, ALAT, GIDH and LDH increased for a short time and then returned closely to normal. During the whole experimental period, the LAP and alkaline phosphatase activities remained in the pathological range, as well as the duration of hexobarbital anaesthesia. Enzyme diagnosis is not suitable for assessing the degree of severity of a liver damage produced by thioacetamide.

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Hexobarbital; Liver; Liver Diseases; Male; Rats; Rats, Inbred Strains; Sleep; Thioacetamide; Time Factors

Topics: 2-Acetylaminofluorene; Acute Disease; Animals; Carbon Tetrachloride; Carcinogens; Chemical and Drug Induced Liver Injury; Dactinomycin; Diet; Ethionine; Hydrocortisone; Liver Neoplasms, Experimental; Methyldimethylaminoazobenzene; Polyribosomes; Protein Biosynthesis; Puromycin; Rats; Rats, Inbred Strains; Saline Solution, Hypertonic; Sparsomycin; Thioacetamide; Time Factors

Topics: Animals; Chemical and Drug Induced Liver Injury; Enzymes; Galactosamine; Glycosaminoglycans; Glycosides; Liver Cirrhosis, Experimental; Liver Diseases; Male; Phosphoadenosine Phosphosulfate; Protein Biosynthesis; Rats; Rats, Inbred Strains; Thioacetamide

Prior administration of aminoacetonitrile (AAN) or imidazole but not isoxazole to rats, was able partially to prevent thioacetamide (TAC)-induced liver necrosis at 24 h. AAN and isoxazole did not prolong the pentobarbital sleeping time of the rats, while imidazole did. These and previous observations suggest a possible participation of non-cytochrome P-450 (P-450)-dependent aminoxidases in TAC activation to a necrogenic metabolite.

Topics: Acetamides; Acetonitriles; Aminoacetonitrile; Animals; Chemical and Drug Induced Liver Injury; Imidazoles; Male; Necrosis; Pentobarbital; Rats; Rats, Inbred Strains; Sleep; Thioacetamide; Time Factors

Topics: Animals; Chemical and Drug Induced Liver Injury; Collagen; Humans; Penicillamine; Rats; Thioacetamide

An enzymatic activity present in rat liver extracts catalyzes the transfer of methyl groups from O6-methylguanine in DNA to protein. This activity was stimulated by treatment of rats with thioacetamide, carbon tetrachloride, 1,2-dimethylhydrazine, diethylnitrosamine, dimethylnitrosamine and by partial hepatectomy but not by treatment with N-methyl-N-nitrosourea or streptozotocin. These results suggest that an enhancement of this activity accompanies the increase in cell division brought about by these agents and is not necessarily a specific response to the presence of alkylated bases in DNA.

Topics: Animals; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; DNA; Guanine; Liver Extracts; Male; Methylation; Proteins; Rats; Rats, Inbred Strains; Thioacetamide; Time Factors

Our previous studies showed that polybrominated biphenyl (PBB) induced hepatic microsomal cytochrome P-450 in dairy cattle but did not elevate hepatic cytosolic ornithine decarboxylase or serum isocitrate dehydrogenase. These enzymes would be expected to increase during hepatotoxic injury and regeneration. Thus, PBB appeared to be a hepatotoxin in rats but not in cattle. In order to identify and confirm the response capability of bovine liver to hepatotoxins, we administered thioacetamide, a hepatotoxin known to induce hepatonecrosis, to a dairy calf. A progression of clinical signs of toxicosis was evident until the animal was moribund by 23 hr postdosing. Histolopathologic alterations in the liver included centrilobular necrosis with congestion and subcapsular microhemmorrhage. Marked changes in serum protein profiles were not noted. However, distinct increases in serum Fe and bilirubin occurred with progressing toxicosis, as did sharp declines in glucose and triglycerides. Serum lactic dehydrogenase, alkaline phosphatase, glutamic-oxaloacetic transaminase, isocitrate dehydrogenase and glutamic-pyruvate transaminase were elevated. Elevation of ornithine decarboxylase was dramatic when compared to the level in normal fetal bovine liver. From studies of its kinetic properties, bovine liver ornithine decarboxylase appears to have an apparent Km for ornithine decarboxylase of .45 mM. Liver homogenates from PBB-treated animals did not form inhibitors to ornithine decarboxylase. Compared with the thioacetamide-treated calf, the normal adult bovine, pregnant adult and 6-month fetus had relative activities of .2 .4 and 5.8%, respectively. These studies show that ornithine decarboxylase is low in liver of normal cattle, but is elevated markedly by agents that cause hepatonecrosis.

Topics: Acetamides; Animals; Blood Glucose; Blood Proteins; Carboxy-Lyases; Cattle; Cattle Diseases; Chemical and Drug Induced Liver Injury; Isocitrate Dehydrogenase; Kidney; Liver; Liver Diseases; Male; Necrosis; Ornithine Decarboxylase; Thioacetamide

The excretion of ascorbic acid and hippuric acid in the urine as liver function tests has no marked advantages when compared with other tests (activities of serum enzymes glutamate dehydrogenase and L-alanine: 2-oxoglutarate aminotransferase, hexobarbital sleeping time).

Topics: Aminopyrine; Animals; Ascorbic Acid; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Female; Hexobarbital; Hippurates; Male; Rats; Sleep; Thioacetamide; Time Factors

Several inhibitors of cytochrome P-450 mediated oxidative transformations, ethyl 2-diethylaminoethyl-2-phenyl-2-ethylmalonate, ethyl-2-diethyl-aminoethyl-2-ethyl-2-buthylmalonate, 2,4 dichloro-6-phenoxyethyl diethylamine, 2-diethylaminoethyl-2-phenyl- (2-propene)-4-penten-1-oate or 3-amino,1,2,4 triazole were not able to significantly prevent thiocetamide induced necrosis at 24 h as evidenced by isocitric acid dehydrogenase activity or histologically. In contrast, several other sulfur containing compounds, tetraethyl thiuramidisulfide, diethyldithiocarbamic acid, thiourea or 1-methyl-2-mercaptoimidazole, which are inhibitors of non-cytochrome P-450 dependent amine oxidase systems, significantly prevented thioacetamide induced liver necrosis at 24 h. Notwithstanding, diphenhydramine, nicotinamide, trimethylamine and imipramine, which are substrates of this amino oxidase system, do not protect. All the chemicals tested prolonged the pentobarbital sleeping time, but there is no correlation between the intensity of this effect and their ability for preventing thioacetamide liver necrosis. These observations suggest that cytochrome P-450 does not play a major role in the activation of thioacetamide to a proximal or an ultimate necrogenic metabolite. Other microsomal enzymes metabolizing sulfur compounds could be involved in the major activation process.

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Liver; Liver Diseases; Male; Necrosis; Pentobarbital; Rats; Thioacetamide

Using Mancini's single radial immunodiffusion technique, the excretion of a liver specific saline soluble antigen was semiquantitatively assayed in the urine of rats with thioacetamine induced hepatic necrosis. The relative amounts of antigen detected in the urine were found to roughly correlate with the extent of necrotic liver parenchyma. It is suggested that a quantitative approach to histuria may provide clinically relevant information on the activity of pathologic processes associated with release of organ specific antigens from degenerative and necrotic lesions into the circulation (histemia) and thence into the urine.

Topics: Animals; Antigens; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Immunodiffusion; Liver; Male; Necrosis; Organ Specificity; Rats; Thioacetamide; Time Factors

Topics: Acetamides; Acid Phosphatase; Alkaline Phosphatase; Animals; Chemical and Drug Induced Liver Injury; Fructose-Bisphosphate Aldolase; Glucuronidase; Isoenzymes; Liver; Oxidoreductases; Rats; Thioacetamide; Transaminases

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Kinetics; Liver; Male; Necrosis; Oxidation-Reduction; Rats; Sulfates; Thioacetamide; Tissue Distribution

In rats, 3 days treatment with paracetamol (1 oral dose of 1 g/kg daily) produced a complete protection against the hepatotoxic actions of a further dose of paracetamol as documented by determination of serum enzyme activities (glutamic-oxaloacetic transaminase, (GOT), glutamic-pyruvic transaminase (GPT), sorbitol dehydrogenase (SDH), bromsulphthalein retention and histological investigations. Subacute paracetamol treatment decreased liver glutathione levels by 46%, liver microsomal cytochrome P-450 content by 23%, hepatic hydroxylation of aniline by 29% and hepatic demethylation of aminopyrine by 46%. It afforded also some protection against the hepatotoxic actions of carbon tetrachloride, bromobenzene and thioacetamide, but did not influence the antiphlogistic activity of paracetamol (carrageenan paw edema test). Plasma and liver concentrations of free paracetamol after oral administration of 1 g/kg paracetamol were somewhat higher in the subacutely paracetamol-pretreated rats than in the non-pretreated control animals whereas no differences in the concentrations of conjugated paracetamol were found between the 2 groups. Pretreatment with paracetamol did not influence the urinary excretion of free paracetamol but caused some shift in the urinary excretion of paracetamol conjugates: pretreated rats excreted 23% less of the paracetamol glucuronide and sulfate and 33% more of the paracetamol mercapturate than the control animals. A depression of the microsomal mixed-function oxidase activity is presumed to be the main cause of the paracetamol-induced protection against paracetamol hepatotoxicity.

Topics: Acetaminophen; Animals; Bromobenzenes; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Drug Interactions; Drug Tolerance; Liver; Liver Function Tests; Male; Mixed Function Oxygenases; Rats; Thioacetamide

Proteins of the small and large ribosomal subunit, isolated at various times from long-term thioacetamide-damaged rat livers, were analysed by two-dimensional polyacrylamide gel electrophoresis and compared with those from normal liver. Chronic hepatic injury induced a number of time-dependent changes of the structural proteins of the small subunit, whereas the proteins of the large subparticle were essentially unaffected. The most significant alterations were an anodical dislocation of protein S6, a strong diminution in the amounts of proteins S9 and S10 and the occurrence of 3 to 4 additional small subunit proteins. By autoradiographic studies it was established that the modifications of S6 were brought about by an enhanced phosphorylation of this protein, which was the earliest sign of a ribosomal alteration in injured liver tissue.

Topics: Animals; Autoradiography; Chemical and Drug Induced Liver Injury; Electrophoresis, Polyacrylamide Gel; Male; Rats; Ribosomal Proteins; Thioacetamide

We describe a mechanized method for centrifugal analyzer determination of sorbitol dehydrogenase in serum, based on conversion of D-fructose to sorbitol with simultaneous oxidation of NADH, in triethanolamine buffer at pH 7.4 and 30 degrees C. The standard curve for this assay is linear to 200 U of activity per liter of serum. The mean within-run precision (CV) of the assay is 0.8%. Results correlate well with those by a spectrophotometric method. In sera from 20 apparently healthy adult humans, sorbitol dehydrogenase activity averaged 1.7 (SD +/- 0.8; range, 1-3) U/L. The mean activity (U/L) for a group of 30 rats was 4.4 (SD, +/- 0.2; range, 3-6); for 20 dogs, 5.8 (SD, +/- 0.7; range 3-9); and for 30 mice, 26.8 (SD +/- 2.1; range, 22-34). To determine the utility of measuring this enzyme in the serum of rats for assessment of hepatotoxicity in drug-safety studies, we compared sorbitol dehydrogenase activity with that of alkaline phosphatase, aspartate aminotransferase, and alanine aminotranferase in the sera of rats treated with thioacetamide or in which the common bile duct has been ligated.

Topics: Adult; Animals; Autoanalysis; Bile Ducts; Centrifugation; Chemical and Drug Induced Liver Injury; Clinical Enzyme Tests; Dogs; Erythrocytes; Humans; Kinetics; L-Iditol 2-Dehydrogenase; Ligation; Male; Mice; Rats; Species Specificity; Sugar Alcohol Dehydrogenases; Thioacetamide

The authors investigated the effects of the administration of thioacetamide, carbon tetrachloride and aminophenazone on the excretion of ascorbic acid and hippuric acid in adult male and female Wistar rats. After a single application of thioacetamide and aminophenazone, the ascorbic acid content in the urine showed a dose-dependent increase, whereas that in the liver had decreased. This increase in the urinary ascorbic acid might be due to a release of stored ascorbic acid from the liver cells. When thioacetamide was given for a prolonged period, the ascorbic acid content in the urine increased at the beginning; later one, at the end of three weeks, it was slightly inferior to the control value. Both single and repeated applications of thioacetamide led to a decrease in the excretion of hippuric acid in the urine, which is attributed to an impairment of the mitochondrial hippuric acid synthesis. Long-term treatment with aminophenazone resulted in an increase of ascorbic acid in the urine, which is indicative of an induction effect, whereas the ascorbic acid content in the liver remained unchanged. There was no effect on the excretion of hippuric acid. In regard to their use in the toxicological evaluation of drugs, these two metabolic effects offer no decisive advantage over current liver function tests.

Topics: Aminopyrine; Animals; Ascorbic Acid; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Enzymes; Female; Hexobarbital; Hippurates; Liver; Liver Function Tests; Male; Rats; Sleep; Thioacetamide; Time Factors

Topics: Acetamides; Age Factors; Animals; Chemical and Drug Induced Liver Injury; Collagen; Disease Models, Animal; Female; Liver; Rats; Thioacetamide

Topics: Acetamides; Animals; Body Weight; Chemical and Drug Induced Liver Injury; Collagen; Female; Hydroxyproline; Liver; Organ Size; Rats; Thioacetamide

NADP-linked dehydrogenases, glucose-6-P dehydrogenase (G 6PDH) 6-P gluconate dehydrogenase (6 PGDH), isocitrate dehydrogenase (ICDH), malate dehydrogenase decarboxylating (ME) and aminotransferases GOT and GPT were analyzed in the soluble fraction of blood free homogenates. Glutmate dehydrogenase (GDH) was assayed in the mitochondrial fraction. TAM was i.p. administered to male albino rats (50 mg/kg/day) for 28 days. enzyme activities were determined as described by Bermeyer 1965 (Methods Enzymatic Analysis. Verlag Chemie. Acad. Press).

Topics: Acetamides; Alanine Transaminase; Alcohol Oxidoreductases; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Glutamate Dehydrogenase; Male; NADP; Rats; Thioacetamide; Transaminases

Topics: Allyl Compounds; Aniline Hydroxylase; Animals; Bromobenzenes; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Dimethylnitrosamine; Ditiocarb; Male; Mice; Sulfhydryl Compounds; Sulfur; Thioacetamide; Thiocarbamates

The hepatotoxic effects of carbon tetrachloride (0.01 ml/kg i.p.), thioacetamide (50 mg/kg intraperitoneally), paracetamol (0.5 g/kg intraperitoneally), and allyl alcohol (0.05 ml/kg intraperitoneally) as estimated by determination of serum enzyme activities (GOT, GPT, SDH) were enhanced in mice treated with one oral dose of 4.8 g/kg ethanol 16 hrs. previously. Pretreatment of mice with ethanol did not increase the hepatotoxic actions of bromobenzene (0.25 ml/kg intraperitoneally), phalloidin (1.5 mg/kg intraperitoneally), alpha-amanitin (0.75 mg/kg intraperitoneally), and praseodymium (12 mg/kg intravenously) though there was a trend to higher enzyme activities in the case of bromobenzene. In guinea-pigs ethanol also aggravated CCl4-induced liver damage, but only strengthened the hepatotoxic activity of D-galactosamine (150 mg/kg intraperitoneally). Treatment with 4.8 g/kg ethanol did not influence liver glutathione levels in mice but increased aniline hydroxylation in the 9000 x g liver homogenate supernatant of mice and guinea-pigs. A dose of 2.4 g/kg ethanol, on the other hand, neither increased aniline hydroxylase activity nor enhanced carbon tetrachloride-induced hepatotoxicity in mice. It is assumed that the enhanced sensitivity to hepatotoxic agents after treatment with ethanol may be due to an enhanced microsomal activation of these substances.

Topics: Acetaminophen; Administration, Oral; Alanine Transaminase; Alcoholic Intoxication; Amanitins; Aniline Hydroxylase; Animals; Aspartate Aminotransferases; Bromobenzenes; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Ethanol; Galactosamine; Glutathione; Humans; L-Iditol 2-Dehydrogenase; Liver; Male; Mice; Microsomes, Liver; Organ Size; Phalloidine; Praseodymium; Thioacetamide

Morphology, biochemistry and neurophysiological comparisons with effects of brain-toxic substances. The acute damage of the liver by thioacetamide is characterized neurophysiologically by a far--reached synchronous beginning of cortical and subcortical alteration of activity, a retardation of cortical and subcortical EEG, threshold increase of the EEG--arousal reaction, reductions in amplitude of centrally evoked potentials and increase of acoustically evoked potentials. We impute that according to an acute "toxic" damage of the liver a "membrane hyperpolarisation" results in all or nearly all areas of the brain. A general decrease of excitability of the brain seems consequently plausible. In opposition to this results only activities of the cortex or structures nearby the cortex (areas above the midbrain reticular formation) will be affected by exogenous arterial hyperammoniemia up to 1700 mug/100 ml.

Topics: Acetamides; Acetates; Acute Disease; Animals; Brain; Brain Diseases; Cats; Chemical and Drug Induced Liver Injury; Electroencephalography; Hepatic Encephalopathy; Phenylacetates; Quaternary Ammonium Compounds; Thioacetamide

Metabolic activation of thioacetamide (CH3CSNH2) to a toxic metabolite which is responsible for its hepatotoxicity and/or its carcinogenicity has been proposed by a number of investigators. In this investigation thioacetamide and one of its metabolites, thioacetamide sulfine (CH3CSONH2), have been compared for their ability to inhibit hepatic mixed-function oxidase enzymes as well as their ability to induce hepatic necrosis. Thioacetamide sulfine was found to decrease aminopyrine N-demethylation and aniline hydroxylation at a lower dose and at an earlier time after administration than was the case with thioacetamide. In addition, at all doses examined, thioacetamide sulfine produced a more severe centrilobular hepatic necrosis than equivalent doses of thioacetamide. To determine whether the hepatic mixed-function oxidase enzyme system was involved in the biotransformation of thioacetamide and/or thioacetamide sulfine to a hepatotoxic compound(s), the severity of liver damage was examined after the administration of an inducer or inhibitors of hepatic mixed-function oxidase enzyme activity. Phenobarbital pretreatment potentiated the hepatic necrosis produced by both thioacetamide and thioacetamide sulfine. In contrast, pyrazole, SKF 525-A, and cobaltous chloride protected against the hepatic necrosis caused by thioacetamide and thioacetamide sulfine. These data suggest that both thioacetamide and thioacetamide sulfine are activated by hepatic mixed-function oxidase enzymes to a hepatotoxic compound(s). These data also suggest that the hepatotoxicity may be mediated by its metabolism to thioacetamide sulfine which, in turn, is metabolized to an ultimate toxic metabolite.

Topics: Acetamides; Aminopyrine; Aniline Compounds; Animals; Chemical and Drug Induced Liver Injury; Drug Interactions; Liver; Liver Diseases; Male; Mixed Function Oxygenases; Necrosis; Oxidoreductases; Phenobarbital; Rats; Sulfonium Compounds; Thioacetamide; Time Factors

The synthesis of glycosaminoglycans in slices from normal and acutely injured rat liver was studied. The rates of incorporation of [14C]-glucosamine into specific types of glycosaminoglycans varied markedly; nearly 90% was incorporated into a fraction containing predominantly heparan sulfate and far less if any heparin; about 9.5% was incorporated into chondroitin 4-and 6-sulfate, and only 0.2% of the radioactivity was found in hyaluronic acid. The rate of synthesis of a fraction having several of the characteristics of keratan sulfate comprised only 0.3% of the synthesis of total glycosaminoglycans. No [14C]hexosamine was incorporated into dermatan sulfate. Following acute hepatic injury, the synthesis of glycosaminoglycans was stimulated by 80 to 100%, and the proportions of various types changed. If calculated on the basis of the specific activity of the precursors of glycosaminoglycans, which was found to be strongly reduced in injured liver, the maximum enhancement of total glycosaminoglycan synthesis was 6.6-fold 5 days after onset of liver injury.

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Glucosamine; Glycosaminoglycans; Heparin; Heparitin Sulfate; In Vitro Techniques; Liver; Liver Diseases; Male; Rats; Thioacetamide

Serum alpha1-fetoprotein (AFP) concentration in 5-week-old rats was measured by the radioimmunoassay technique after a single administration of various hepatotoxins. Marked elevation of serum AFP concentrations occurred in rats treated with carbon tetrachloride, thioacetamide, D-galactosamine, allyl alcohol, allyl formate, and ethionine in 4 days of these treatments. The increased production of AFP appeared to be correlated with the induction of liver glucose-6-phosphate dehydrogenase (G-6-PD) among biochemical parameters studied for hepatocellular injuries. However, the difference in time courses of the increase in liver G-6-PD activity and serum AFP level following CC14 treatment suggested that the increased production of serum AFP and the induction of G-6-PD in injured liver were caused by closely related but different mechanisms. Pretreatment of CC14-injured rats with N,N'-diphenyl-p-phenylenediamine or aminoacetonitrile was effective not only in lowering the increased level of serum AFP and liver G-6-PD but also in preventing liver cell necrosis and steatosis induced by CC14. Treatment with a lower dose of thioacetamide resulted in littel elevation of serum AFP and liver G-6-PD with a markedly increased incorporation of 3H-thymidine into liver DNA without any evidence of liver injury. On the other hand, the administration of ethionine, which caused little necrosis of liver cells, produced increase in both serum AFP and liver G-6-PD levels with an only small increase of hepatic DNA synthesis compared to those following thioacetamide as well as CC14. These results suggest that the elevation of serum AFP is not directly related to the stimulation of hepatic DNA synthesis. Some additional mechanisms of specific gene amplification for AFP, which is geared to hepatic injury per se, appear to play a major role in the increased AFP production in injured liver.

Topics: alpha-Fetoproteins; Aminoacetonitrile; Animals; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; DNA; Ethionine; Fetal Proteins; Glucosephosphate Dehydrogenase; Liver Diseases; Male; Rats; Thioacetamide

The temporal sequence of alpha-fetoprotein appearance in serum was determined in both necrogenic and nonnecrogenic liver injury. Ethionine, thioacetamide, and CCl4 were used to intoxicate male and female rats for evaluating serum enzyme levels, mitotic indices, and morphological reflections of impairment. Thioacetamide- and CCl4-induced cell death preceded the mitotic wave in residual hepatocytes, and, in the case of both agents, this intoxicant-mediated necrosis preceded the emergence of alpha-fetoprotein. Yet, although there was no evidence of either cell destruction or significant mitotic activity in ethionine-poisoned animals, serum alpha-fetoprotein levels progressively increased. Thus the temporal sequence of alpha-fetoprotein synthesis and/or release and cellular reorganization for regeneration suggests that reappearance of the protein macro-molecule is an expression of the altered phenotype observed during the "step-down" phase of liver regeneration.

Topics: Alanine Transaminase; alpha-Fetoproteins; Animals; Aspartate Aminotransferases; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Ethionine; Female; Liver Diseases; Liver Regeneration; Male; Mitosis; Necrosis; Rats; Thioacetamide; Time Factors

The orderly organization in a number of discrete classes of weight persists in the hepatocytes during acute and chronic poisoning with thioacetamide and during a prolonged treatment with hydrocortisone, though many striking cytological and structural changes occur in the liver. The number of hepatocyte classes decreases under hydrocortisone treatment and during acute and chronic thioacetamide poisoning, and increases during recovery after acute thioacetamide poisoning and during the late phases of chronic thioacetamide poisoning. This is due to decrements and increments in dry mass of the hepatocytes, which occur by steps, through repeated losses and additions of a constant amount of solids substantially corresponding to the class period. Such a mechanism is similar to that acting in the hepatocyte atrophy due to starvation and in the hepatocyte enlargement occurring during postnatal development. Therefore, the increment and the decrement in dry mass by defined steps takes place in the hepatocytes in both physiological and pathological conditions.

Topics: Acetamides; Animals; Biometry; Body Weight; Cell Count; Chemical and Drug Induced Liver Injury; Cricetinae; Dose-Response Relationship, Drug; Female; Hydrocortisone; Karyometry; Liver; Male; Mitosis; Organ Size; Rats; Thioacetamide; Water

The metabolism of calcium and magnesium in liver of thioacetamide treated rats has been studied. A change in the semipermeability of the cell membrane to calcium, magnesium, sodium and potassium was observed. The variations in the concentration of extra- and intracellular cations indicates that an undiscriminated in- and outflux of those ions takes place at the time of highest calcium deposition. This change in the cell membrane permeability seems to be related to modifications in the phospholipid metabolism. An increased incorporation of 32P into the acidic phospholipids (phosphatidyl ethanolamine and phosphatidyl serine) suggests their involvement in the physiological changes of the cell membrane. The results also point out the existence of a hormonally determined susceptibility of the cell membrane to undergo those changes.

Topics: Acetamides; Animals; Calcium; Cell Membrane Permeability; Chemical and Drug Induced Liver Injury; Female; Liver; Magnesium; Male; Phosphatidylethanolamines; Phospholipids; Phosphorus; Potassium; Rats; Sex Factors; Sodium; Subcellular Fractions; Thioacetamide

Rats have been treated for 6 weeks with thioacetamide (0.1% in drinking water). The biochemical changes in liver microsomal metabolism of estradiol which are similar to those observed in human liver cirrhosis become already apparent after one week of treatment. These are diminishment of hepatic microsomal cytochromes P-450 and b5, comparable decrease of 2-hydroxylation and increase of formation of estrone from estradiol. The alterations of estrogen metabolism are reversible within two weeks after ending thioacetamide treatment. These data correspond to the already well established histological response of rat liver to thioacetamide, and its reversibility.

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Cytochromes; Estradiol; Estrone; In Vitro Techniques; Microsomes, Liver; Rats; Steroid Hydroxylases; Thioacetamide; Time Factors

Arginine vasopressin was infused into the V. portae and into the V. cava of unanesthetized rats in water diuresis. The differential antidiuretic response of the same animal to these infusions was used to calculate extraction fraction of ADH by the liver. In the normal rat no extraction was detected. The liver of rats hydrated with 5% ethanol extracted 10% and that of rats treated with thioacetamide extracted 60% of the ADH infused into the portal vein. It is postulated that disturbances of liver cell function by narcotics and substances causing liver damage may liberate ADH-destroying ferments into the blood.

Topics: Acetamides; Animals; Arginine Vasopressin; Chemical and Drug Induced Liver Injury; Diuresis; Ethanol; Female; Liver; Rats; Thioacetamide; Vasopressins

Pyrrolizidine alkaloids have long been considered to be hepatotoxic in man as well as in grazing animals. To investigate the effect of liver cell division induced by thioacetamide on the hepatic changes induced by these alkaloids, rats were treated concurrently with thioacetamide and the pyrrolizidine alkaloid lasiocarpine. Thioacetamide was given intraperitoneally in a dose of 50 mg/kg b. wt twice weekly and lasiocarpine was administered in the diet at a concentration of 50 ppm. At 15 weeks, the combination of thioacetamide and lasiocarpine produced numerous grossly visible grey nodules in livers of 26 of 30 rats. Microscopically, these livers revealed a severe degree of postnecrotic cirrhosis and numerous hyperplastic nodules. The cells in most nodules were arranged in solid sheets or in a trabecular pattern and shown atypia, mitosis and hyperchromasia. In contrast, there was no evidence of cirrhosis or nodule formation in livers of animals treated with either lasiocarpine or thioacetamide alone. The rapid development of liver lesions in rats treated simultaneously with low doses of lasiocarpine and thioacetamide suggests that cell proliferation accentuates the development of neoplasia.ł

Topics: Acetamides; Animals; Carcinogens; Cell Division; Chemical and Drug Induced Liver Injury; Drug Combinations; Hyperplasia; Liver; Liver Cirrhosis, Experimental; Liver Neoplasms; Male; Neoplasms, Experimental; Pyrrolizidine Alkaloids; Rats; Thioacetamide

Topics: 1-Propanol; Acetaldehyde; Acetamides; Alanine Transaminase; Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Dimethylnitrosamine; Drug Synergism; Ethanol; Lipid Metabolism; Liver; Male; Microsomes, Liver; Mixed Function Oxygenases; Nitrosamines; Rats; Thioacetamide

Liver microsomes of rats poisoned with thioacetamide show a significant reduction of cytochrome P-450. Consequently, oxidative reactions of drug metabolism and the estrogen 2-hydroxylase are diminished. Enhancement of microsomal transformation of estradiol to estrone and 16alpha-hydroxyestrone is observed after treatment of rats with thioacetamide, due to diminished metabolism of estradiol by the alternative oxidation at C-2. Estriol formation is reduced by thioacetamide pretreatment. These changes in estrogen breakdown closely correlate with those observed in humans suffering from cirrhosis of the liver. It is concluded that the thioacetamide poisoned rat should be an experimental model suitable for studying estrogen metabolism in liver injury.

Topics: Acetamides; Aminopyrine N-Demethylase; Aniline Hydroxylase; Animals; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Disease Models, Animal; Estradiol; Estriol; Estrogens; Estrone; Liver Cirrhosis; Microsomes, Liver; Rats; Steroid Hydroxylases; Thioacetamide

Topics: Acetamides; Animals; Cats; Chemical and Drug Induced Liver Injury; Liver; Models, Biological; Necrosis; Thioacetamide

Topics: Acetamides; Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Female; Heparinoids; Iodine Radioisotopes; Male; Rats; Rose Bengal; Thioacetamide

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Body Temperature; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Female; Heparinoids; Liver; Liver Diseases; Male; Necrosis; Rats; Thioacetamide

Topics: Alanine Transaminase; Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Male; Medicine, East Asian Traditional; Mice; Plant Extracts; Plants, Medicinal; Quinestrol; Rabbits; Rats; Thioacetamide

Topics: Acetamides; Adenosine Triphosphatases; Alanine Transaminase; Animals; Aspartate Aminotransferases; Bile; Bilirubin; Body Temperature; Chemical and Drug Induced Liver Injury; Cholesterol; Histocytochemistry; Liver; Male; Morpholines; Potassium; Quinazolines; Rats; Sodium; Thioacetamide; Thiocyanates; Time Factors; Water

Topics: Animals; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; Endoplasmic Reticulum; Glycogen; Hyperplasia; Liver; Liver Cirrhosis; Liver Neoplasms; Male; Microscopy, Electron; Rats; Ribosomes; Thioacetamide; Time Factors; Water

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Endoplasmic Reticulum; Hepatectomy; Karyometry; Liver Cirrhosis; Liver Regeneration; Male; Methods; Mitosis; Photometry; Rats; RNA; Thioacetamide

Topics: Acetamides; Animals; Chemical and Drug Induced Liver Injury; Microsomes, Liver; Phospholipids; Thioacetamide

Thioacetamide given orally to rats produces centrolobular hepatic necrosis and also causes death of the cells in the terminal portion of the proximal renal tubule. The morphologic changes observed during the course of the renal toxicity include the early and transient appearance of apical dense bodies, which appear to fuse to form large lysosomes, and the appearance of nucleolar hypertrophy, reminiscent of the same change seen in the hepatocytes. In addition a variety of changes described in lethally injured tubular cells in other toxicities appear. A diuresis, which lasts for 5 days, coincides with the appearance of tubular cell destruction. The mechanism of cell injury due to thioacetamide is not identified, but the temporal sequence of morphologic and physiologic change is consistent with both a relative concentration of the thioacetamide in the proximal tubule and its potential conversion to a putative proximate toxin.

Topics: Acetamides; Animals; Cell Nucleolus; Chemical and Drug Induced Liver Injury; Diuresis; Kidney Diseases; Kidney Tubules, Proximal; Lysosomes; Male; Microscopy, Electron; Rats; Thioacetamide

Topics: Acetamides; Alanine Transaminase; Alcohols; Allyl Compounds; Animals; Benzene Derivatives; Body Temperature; Bromine; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Dibenzylchlorethamine; Dose-Response Relationship, Drug; Female; Hydrocarbons, Brominated; Lethal Dose 50; Liver; Male; Mice; Nitrosamines; Phenoxybenzamine; Quinolines; Rats; Thioacetamide; Time Factors; Tolazoline; Triglycerides

1. The effects of the inclusion of thioacetamide in the diet on the properties of rat liver nuclei were studied both in adolescent rats, in which the parenchymal cells contain diploid nuclei, and in young adult rats, with a high proportion of tetraploid nuclei. 2. These investigations included a survey of the sedimentation properties of the nuclei, the nuclear volumes, content of DNA, RNA and protein, the incorporation in vivo of [(3)H]thymidine into DNA and [(14)C]orotate into RNA, and measurements of the activity of RNA polymerase and ribonuclease. These studies were conducted on nuclei fractionated by zonal centrifugation. 3. In both groups of animals, exposure to thioacetamide produced large numbers of nuclei that were abnormal in their chemical composition and enzymic activity. The changes were complex as regards both the types of nuclei that were affected and in their variation with time. 4. In adolescent rats two waves of synthesis of DNA and RNA were observed, one at 3 days and the other after 2 weeks of treatment. The first decline in the incorporations into both DNA and RNA coincided with a decrease in the pool sizes of some of the precursors. The activity of RNA polymerase was not substantially altered. A marked increase in the content of protein was observed before the first wave of synthesis. The normal progressive increase in tetraploid nuclei was prevented. 5. In young adult rats two waves of DNA synthesis were detected. Each was preceded by a large increase in the amount of protein per nucleus but was not accompanied by increased RNA synthesis. After 4 weeks of treatment, the diploid stromal nuclei appeared mainly unaffected and large numbers of tetraploid nuclei with a greatly increased quantity of protein were observed.

Topics: Acetamides; Aging; Animals; Carbon Isotopes; Cell Nucleus; Centrifugation, Zonal; Chemical and Drug Induced Liver Injury; Chromatography; DNA; DNA-Directed RNA Polymerases; Glucose-6-Phosphatase; Liver; Male; Proteins; Rats; Ribonucleases; RNA; Thioacetamide; Thymine Nucleotides; Tritium; Ultraviolet Rays

Topics: Acetamides; Animals; Carcinoma, Hepatocellular; Cell Nucleus; Chemical and Drug Induced Liver Injury; Hepatectomy; Liver; Liver Cirrhosis; Liver Neoplasms; Liver Regeneration; Mitosis; Neoplasms, Experimental; Precancerous Conditions; Rats; Thioacetamide

Topics: Alcohol Oxidoreductases; Animals; Chemical and Drug Induced Liver Injury; Chronic Disease; Endoplasmic Reticulum; Glucuronates; Guinea Pigs; Intestinal Mucosa; Kidney; Liver; Male; Microscopy, Electron; Thioacetamide; Time Factors; Uracil Nucleotides

Topics: Acetamides; Animals; Cell Nucleolus; Chemical and Drug Induced Liver Injury; Chronic Disease; Edema; Hepatectomy; Karyometry; Liver Regeneration; Male; Photometry; Rats; Thioacetamide; Time Factors

1. In normal rats the amounts of each of the main types of nuclear protein, i.e. soluble proteins, histones, non-histone chromosomal proteins and residual proteins, vary within the different classes of rat liver nuclei fractionated by zonal centrifugation. 2. Heterogeneity is observed in the non-histone chromosomal proteins prepared from different classes of liver nuclei. These differences were observed by analysis of the proteins both by sodium dodecyl sulphate-polyacrylamide-gel electrophoresis and electrofocusing electrophoresis. They are most evident between the non-histone chromosomal proteins obtained from stromal and parenchymal nuclei. However, some differences are also found for the parenchymal nuclei, between the diploid parenchymal and the tetraploid parenchymal, and between them and the nuclei involved in the synthesis of DNA respectively. 3. Drastic alterations in the nuclear proteins are found after the administration of thioacetamide. The changes observed are complex and not uniform. They vary with the age of the animal and the type of nucleus. In general an increase in the soluble proteins and non-histone chromosomal proteins and a decrease in the residual proteins is observed. There is a decrease in the specific radioactivity of soluble and residual proteins. 4. Electrophoretic analysis of the non-histone chromosomal proteins showed that specific changes occurred after administration of thioacetamide, which are different in adolescent and young adult rats.

Topics: Acetamides; Age Factors; Amino Acids; Animals; Carbon Isotopes; Cell Nucleus; Centrifugation, Zonal; Chemical and Drug Induced Liver Injury; Chromosomes; DNA; Electrophoresis, Polyacrylamide Gel; Isoelectric Focusing; Liver; Male; Protein Hydrolysates; Proteins; Rats; Thioacetamide

Topics: Acetamides; Alanine Transaminase; Alcohols; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Flavonoids; Glutamate Dehydrogenase; Male; Oxidoreductases; Rats; Sorbitol; Thioacetamide; Time Factors

Topics: Acetamides; Alanine Transaminase; Amino Acids; Animals; Aspartate Aminotransferases; Chemical and Drug Induced Liver Injury; Clinical Enzyme Tests; Dose-Response Relationship, Drug; Ethanolamines; Fructose-Bisphosphate Aldolase; Glutamate Dehydrogenase; Isocitrate Dehydrogenase; L-Lactate Dehydrogenase; Liver; Malate Dehydrogenase; Male; Microscopy, Electron; Nitrosamines; Organ Size; Rats; Thioacetamide; Time Factors; Urea

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Cholestasis; Cholinesterases; Clinical Enzyme Tests; Diagnosis, Differential; Ethionine; Fatty Liver; Fructose-Bisphosphate Aldolase; Fructosephosphates; Necrosis; Phenobarbital; Proadifen; Rats; Thioacetamide

Topics: Agar; Animals; Biopsy; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Electrophoresis; Gels; Hepatitis; Histocytochemistry; Humans; Liver Cirrhosis; Liver Diseases; Proteins; Rabbits; Rats; Thioacetamide

Topics: Acetamides; Animals; Aspartate Aminotransferases; Bilirubin; Chemical and Drug Induced Liver Injury; Coloring Agents; Dogs; Histiocytes; Histocytochemistry; Iodine Radioisotopes; L-Lactate Dehydrogenase; Liver Cirrhosis, Experimental; Liver Function Tests; Radionuclide Imaging; Thioacetamide

Topics: Amides; Chemical and Drug Induced Liver Injury; Copper; Hepatitis; Histocytochemistry; Pathology; Pharmacology; Rats; Research; Sulfhydryl Compounds; Thioacetamide; Toxicology

Topics: Amides; Bilirubin; Blood Chemical Analysis; Carbon Tetrachloride; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Hepatitis; Hepatitis A; Isocitrate Dehydrogenase; Necrosis; Ouabain; Pathology; Pharmacology; Promethazine; Pyruvates; Rats; Research; Sulfhydryl Compounds; Thioacetamide; Toxicology; Transaminases

Topics: Amides; Carbon Isotopes; Chemical and Drug Induced Liver Injury; Electrons; Hepatitis; Hepatocytes; Leucine; Liver; Microscopy; Microscopy, Electron; Pharmacology; Proteins; Rats; Research; Ribosomes; RNA; Serum Albumin; Sulfhydryl Compounds; Thioacetamide; Toxicology

Topics: Chemical and Drug Induced Liver Injury; Cytoplasm; Dactinomycin; Hepatitis; Liver Regeneration; Rats; Thioacetamide; Toxicology

Topics: Amides; Antifungal Agents; Chemical and Drug Induced Liver Injury; Hepatitis; Liver Cirrhosis; Rats; Research; Sulfhydryl Compounds; Thioacetamide; Toxicology

Topics: Amides; Autoradiography; Cell Nucleus; Chemical and Drug Induced Liver Injury; Cytoplasm; DNA; Hepatitis; Liver; Rats; Research; RNA; Sulfhydryl Compounds; Thioacetamide; Toxicology; Tritium

Topics: Amides; Cell Nucleolus; Cell Nucleus; Chemical and Drug Induced Liver Injury; Hepatitis; Liver; Liver Cirrhosis; Pathology; Pharmacology; Rats; Research; Sulfhydryl Compounds; Thioacetamide; Toxicology

Topics: Amides; Animals; Chemical and Drug Induced Liver Injury; Hepatitis; Hepatitis A; Magnesium; Rats; Sulfhydryl Compounds; Thioacetamide; Thiosulfates

Topics: Amides; Cell Nucleolus; Cell Nucleus; Chemical and Drug Induced Liver Injury; Hepatitis; Hepatocytes; Liver; Pathology; Research; Sulfhydryl Compounds; Thioacetamide; Toxicology