ascorbic-acid and Necrosis

Ascorbic acid or Vitamin C is a potent dietary antioxidant with a double faced character, in that it exhibits a pro-oxidant activity arising from its routine antioxidant property that generates reactive free radicals, which induce cytotoxic effects at pharmacologic concentrations. A systematic review of this effect of ascorbic acid in the oral tumours and normal oral tissues would clearly elucidate the merits or demerits of employing vitamin C in treating the same.. The aim of our systematic review is to critically review the studies reported in literature that have studied the pro-oxidant activity of ascorbic acid as a therapeutic option for treatment of oral neoplasms and its effects on normal oral cells.. Articles were searched in PUBMED, MEDLINE using appropriate key words like "ascorbic acid", "pro-oxidant activity", "treatment", "oral neoplasms". Hand search of Journals was also performed. Articles were reviewed and analysed.. The search strategy included 17 potentially relevant articles for review of which, 12 were in vitro studies; 3 were in vivo animal studies; 1 was in vivo human study and 1 was ex vivo human study. The optimum concentration of ascorbic acid used to produce potential pro-oxidant associated cytotoxic effects was found to be 3-5mM in vitro, 0.88-5mM in vivo animals, 0.5-2mM ex vivo in humans, and the corresponding effects are induction of apoptosis (caspase activation), necrosis, free radical formation, H2O2 generation, and DNA fragmentation. In contrast, the same pro-oxidant concentrations had no effect on the normal cells.. The results of our systematic review show that the pro-oxidant activity of pharmacologic ascorbic acid is a part of its dose-dependent bimodal activity and is a result of the proposed Fenton mechanism. In vitro, animal and ex vivo studies of pharmacologic ascorbic acid (AA) have yielded meritorious results proving vitamin C as an effective cytotoxic agent against oral neoplastic cells with potentially no harming effects on normal cells. However, a shortage of clinical trials and in vivo human studies pertaining to evaluation of anti-tumour activity of vitamin C in tumours of oral cavity remains a lacuna in concluding ascorbic acid as a beneficial therapeutic option in treatment of oral neoplasms.

Topics: Animals; Antineoplastic Agents; Apoptosis; Ascorbic Acid; DNA Fragmentation; Free Radicals; Humans; Hydrogen Peroxide; Mouth Mucosa; Mouth Neoplasms; Necrosis; Oxidants

Vitamin C (VC) and vitamin K(3) (VK(3)) administered in a VC:VK(3) ratio of 100:1 exhibit synergistic antitumor activity and preferentially kill tumor cells by autoschizis, a novel type of necrosis characterized by exaggerated membrane damage and progressive loss of organelle-free cytoplasm through a series of self-excisions. During this process, the nucleus becomes smaller, cell size decreases one-half to one-third of its original size, and most organelles surround an intact nucleus in a narrow rim of cytoplasm. While the mitochondria are condensed, tumor cell death does not result from ATP depletion. However, vitamin treatment induces a G(1)/S block, diminishes DNA synthesis, increases H(2)O(2) production, and decreases cellular thiol levels. These effects can be prevented by the addition of catalase to scavenge the H(2)O(2). There is a concurrent 8- to 10-fold increase in intracellular Ca(2+) levels. Electrophoretic analysis of DNA reveals degradation due to the caspase-3-independent reactivation of deoxyribonuclease I and II (DNase I, DNase II). Redox cycling of the vitamins is believed to increase oxidative stress until it surpasses the reducing ability of cellular thiols and induces Ca(2+) release, which triggers activation of Ca(2+)-dependent DNase and leads to degradation of DNA. Recent experiments indicate that oral VC:VK(3) increases the life-span of tumor-bearing nude mice and significantly reduces the growth rate of solid tumors without any significant toxicity by reactivating DNase I and II and inducing autoschizis. This report discusses the mechanisms of action employed by these vitamins to induce tumor-specific death by autoschizis.

Topics: Animals; Antioxidants; Ascorbic Acid; Cell Death; Humans; Necrosis; Neoplasms; Oxidative Stress; Vitamin K

Fatale haemoptysis occurred as a result of circumferential caustic erosion to the right intermediate bronchus caused by a tablet of ferrous sulphate which remained in contact for 4 days. The necrotic process continued, after removal of the foreign body, in the bronchial wall and its vessels. We suggest local bronchial lavage with 1% bicarbonate saline during extraction of the tablet and subsequent follow-up fibroscopies. The discovery of a necrotic ulceration of the bronchus requires strict medico-surgical surveillance in order to rapidly intervene under cover of selective intubation when necessary.

Topics: Accidents, Home; Ascorbic Acid; Burns, Inhalation; Caustics; Female; Ferrous Compounds; Hemoptysis; Humans; Lung; Middle Aged; Necrosis; Tablets

There is a growing body of evidence for the role of free radicals in mediating myocardial tissue injury during myocardial ischemia and in particular during the phase of myocardial reoxygenation. Associated with myocardial ischemia and reperfusion is the generation of oxygen-derived free radicals from a variety of sources that include the mitochondrial electron transport chain; the biosynthesis of prostaglandins; the enzyme xanthine oxidase; and circulating elements in the blood, with the polymorphonuclear neutrophil assuming a primary focus of attention. Experimental studies have shown that free radical scavengers (e.g., N-[2-mercaptopropionyl]glycine) and enzymes that scavenge or degrade reactive species of oxygen (superoxide dismutase or catalase) can reduce the mass of myocardial tissue that undergoes irreversible injury. Additionally allopurinol, which inhibits the enzyme xanthine oxidase, reduces ultimate infarct size, putatively by reducing the xanthine oxidase generation of superoxide anion. Neutrophils that enter the ischemically injured myocardium under the influence of chemotactic attraction and activation of the complement system generate and release highly reactive and cytotoxic oxygen derivatives that are destructive to the vascular endothelium and to the cardiac myocytes. Studies have documented that neutrophil depletion or suppression of neutrophil function (ibuprofen, nafazatrom, BW 755C, or more recently with prostacyclin or iloprost) results in a significant salvage of myocardial tissue that is subjected to a period of regional ischemia followed by reperfusion. Our current understanding of the events associated with myocardial ischemia suggests that within the ischemic myocardial region or area at risk, there is a population of cells that are reversibly injured and that reperfusion within a specified period (less than 3 hours) of time is capable of restoring the majority of the jeopardized cells to a normal status, but that the act of reperfusion itself will lead to the sudden demise of a fraction of the cells because of the cytotoxic effects of reactive species of oxygen derived from one or more of the sources indicated above. The efforts to minimize the amount of tissue that undergoes cell death as a result of myocardial ischemia demand that early reperfusion be established. However, the reintroduction of molecular oxygen and the circulating elements of the blood will be associated with an "explosive" and self-limited destruction of so

Topics: Antioxidants; Ascorbic Acid; Cell Adhesion; Coronary Disease; Free Radicals; Glycoproteins; Humans; Lysosomes; Myocardial Infarction; Myocardium; Necrosis; Neutrophils; Oxygen; Superoxide Dismutase; Xanthine Oxidase

Vitamin C deficiency is found in patients with variable kidney diseases. However, the role of vitamin C as an epigenetic regulator in renal homeostasis and pathogenesis remains largely unknown.. Integrated evidence suggested that epigenetic modifications affected the proximal tubule cells and fenestrated endothelial cells, leading to tubule injury and hypoxia through transcriptional regulation. Strikingly, loss of DNA hydroxymethylation and DNA hypermethylation in vitamin C-deficient kidneys preceded the histologic sign of tubule necrosis, indicating the causality of vitamin C-induced epigenetic modification in ATN. Consistently, prophylactic supplementation of an oxidation-resistant vitamin C derivative, ascorbyl phosphate magnesium, promoted DNA demethylation and prevented the progression of cisplatin-induced ATN.. Vitamin C played a critical role in renal homeostasis and pathogenesis in a mouse model, suggesting vitamin supplementation may be an approach to lower the risk of kidney injury.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Disease Models, Animal; Endothelial Cells; Epigenesis, Genetic; Female; Humans; Kidney Tubular Necrosis, Acute; Male; Mice; Necrosis; RNA

To explore the protective effect and its mechanism of vitamin C on septic renal injury induced by lipopolysaccharide (LPS).. Renal tubular epithelial cells HK-2 were induced with 10 mg/L LPS for 8 hours and 12 hours, respectively, and then 0.5 mmol/L and 1 mmol/L vitamin C were added, respectively. Cell viability was measured using cell proliferation and toxicity assay cell counting kit-8 (CCK-8) to determine suitable condition for subsequent experiments. HK-2 cells were divided into control group, LPS group and LPS+vitamin C group (LPS+VC group). The contents of necrosis factors phosphorylated mixed lineage kinase domain-like protein (p-MLKL) and phosphorylated receptor-interacting protein kinase 3 (p-RIPK3) were measured by Western blotting. The contents of inflammatory factors interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were determined by enzyme linked immunosorbent assay (ELISA) in each group. Differences among the groups were compared.. CCK-8 showed that 1 mmol/L vitamin C improved the survival rate of HK-2 cells to 86% after 12 hours of LPS induction, so this condition was selected for subsequent experiments. After 12 hours LPS induction in HK-2 cells, the expressions of p-MLKL and p-RIPK3 were significantly higher than those of the control group, and the levels of IL-1β and TNF-α were also significantly higher than those of the control group [IL-1β (ng/L): 23.2±1.4 vs. 12.8±3.9, TNF-α (ng/L): 36.4±3.9 vs. 11.6±1.8, both P < 0.05], indicating the co-existence of cell necrosis and inflammation. Compared with LPS group, 1 mmol/L vitamin C significantly decreased the protein expression of p-MLKL and p-RIPK3, and also significantly decreased the levels of IL-1β and TNF-α [IL-1β (ng/L): 19.8±0.7 vs. 23.2±1.4, TNF-α (ng/L): 17.4±5.8 vs. 36.4±3.9, both P < 0.05].. Vitamin C can alleviate LPS-induced HK-2 cell damage, and reduce the expressions of necrotic factors and inflammatory factors.

Topics: Ascorbic Acid; Humans; Interleukin-1beta; Kidney; Lipopolysaccharides; Necrosis; Tumor Necrosis Factor-alpha

Topics: Antibodies; Ascorbic Acid; Cullin Proteins; F-Box-WD Repeat-Containing Protein 7; Gene Expression; Humans; Necrosis; Nicotiana; Plant Diseases; Plant Leaves; Plants, Genetically Modified; Recombinant Proteins; Transgenes

Although conventional bowel preparation for colonoscopy rarely causes serious complications, such complications can be fatal and, therefore, require early recognition and prompt treatment. Herein, we report a case of non-occlusive mesenteric ischemia (NOMI) induced by polyethylene glycol with an ascorbate component (PEG + Asc) that was used as a colonic bowel preparation. An- 82-year-old woman with a medical history of hypertension, atrial fibrillation and mild chronic renal failure received a cancer screening colonoscopy. Four hours after the administration of PEG + Asc, she vomited and gradually developed abdominal distention. She went into hypovolemic shock, and a CT scan revealed a distal colon obstruction caused by fecal material. A colonoscopy identified focal necrotic mucosa between the rectum and descending colon, suggesting the occurrence of irreversible intestinal necrosis; consequently, she underwent emergency surgery. The operative and pathological findings showed a discontinuous area of necrosis from the anal margin to the ileum without thrombotic change in the main mesenteric arteries, consistent with a diagnosis of NOMI. NOMI is a rare but fatal disease that can advance to an irreversible stage before a definite diagnosis can be made. Since PEG + Asc is a hypertonic laxative solution, the possibility that dehydration might cause severe secondary complications must be considered.

Topics: Aged, 80 and over; Ascorbic Acid; Colon; Colonoscopy; Female; Humans; Ileum; Laxatives; Mesenteric Ischemia; Necrosis; Polyethylene Glycols

Topotecan, a derivative of camptothecin, is an important anticancer drug for the treatment of various human cancers in the clinic. While the principal mechanism of tumor cell killing by topotecan is due to its interactions with topoisomerase I, other mechanisms, e.g., oxidative stress induced by reactive free radicals, have also been proposed. However, very little is known about how topotecan induces free radical-dependent oxidative stress in tumor cells. In this report we describe the formation of a topotecan radical, catalyzed by a peroxidase-hydrogen peroxide system. While this topotecan radical did not undergo oxidation-reduction with molecular O

Topics: Antineoplastic Agents; Ascorbic Acid; Cell Death; Cysteine; DNA Topoisomerases, Type I; Drug Combinations; Drug Synergism; Gene Expression; Glutathione; Humans; Hydrogen Peroxide; MCF-7 Cells; Necrosis; Oxidation-Reduction; Peroxidase; Reactive Oxygen Species; Topoisomerase I Inhibitors; Topotecan

Ascorbic acid induces apoptosis, autophagy, and necrotic cell death in cancer cells. We investigated the mechanisms by which ascorbic acid induces death in laryngeal squamous cell carcinoma Hep2 cells. Ascorbic acid markedly reduced cell viability and induced death without caspase activation and an increase in cytochrome c. Hep2 cells exposed to ascorbic acid exhibited membrane rupture and swelling, the morphological characteristics of necrotic cell death. The generation of reactive oxygen species (ROS) was increased in Hep2 cells treated with ascorbic acid, and pretreatment with N-acetylcysteine blocked ascorbic acid-induced cell death. Ascorbic acid also stimulated protein kinase C (PKC) signaling, especially PKC α/β activation, and subsequently increased cytosolic calcium levels. However, ascorbic acid-induced necrotic cell death was inhibited by Ro-31-8425 (PKC inhibitor) and BAPTA-AM (cytosolic calcium-selective chelator). ROS scavenger NAC inhibited PKC activation induced by ascorbic acid and Ro-31-8425 suppressed the level of cytosolic calcium increased by ascorbic acid, indicating that ROS is represented as an upstream signal of PKC pathway and PKC activation leads to the release of calcium into the cytosol, which ultimately regulates the induction of necrosis in ascorbic acid-treated Hep2 cells. These data demonstrate that ascorbic acid induces necrotic cell death through ROS generation, PKC activation, and cytosolic calcium signaling in Hep2 cells. J. Cell. Physiol. 232: 417-425, 2017. © 2016 Wiley Periodicals, Inc.

Topics: Apoptosis; Ascorbic Acid; Calcium; Calcium Signaling; Carcinoma, Squamous Cell; Cell Line, Tumor; Enzyme Activation; Humans; Laryngeal Neoplasms; Necrosis; Protein Kinase C; Reactive Oxygen Species

Endosulfan, a chlorinated hydrocarbon insecticide/acaricide, is a member of a cyclodiene sub-group of poisons to a wide variety of insects and mites. It is also toxic to humans and animals, but there is limited knowledge about endosulfan-related splenic and overall immunotoxicity. The aim of this study was to review pathological findings of endosulfan toxicity in the spleen and to examine potential protective effects of the anti-oxidant Vitamin C (Vit C). Here, after 6-week exposures, the spleens of New Zealand White rabbits were examined grossly and histopathologically and tissue caspase-3 activity was assessed immunohistochemically. Rabbits in four groups were used: Group END were given by oral gavage a sub-lethal dose of endosulfan (1 mg/kg) in corn oil daily for 6 weeks; Group END + C received the same dose of endosulfan daily and Vit C (20 mg/kg) every other day by gavage during this period; Group Vit C received oral corn oil daily and 20 mg/kg Vit C every other day; and Group OIL received corn oil daily for 6 weeks. Analyses of the tissues collected 1 week after the final dosing revealed lymphocyte depletion and necrosis in spleens of the hosts that received the pesticide (END only and END + C); hemorrhage and slight neutrophilic infiltration was also noted. Caspase-3 immunoreactivity was marked in lymphocytes in all spleens of rabbits in both END groups. Overall, these toxicities were mitigated by Vit C co-treatment; in END + C hosts, markedly decreased depletion of lymphocytes, inflammation and caspase-3 immunoreactivity were observed. However, even with mitigation, the level of toxicity present was still greater than any seen in the spleens of hosts that received OIL or Vit C alone. These results revealed endosulfan could cause toxicity in the rabbit spleen, characterized by depletion of lymphocytes, inflammation, necrosis and hemorrhage, and that this toxicity could begin to be mitigated by Vit C co-treatment.

Topics: Animals; Antioxidants; Ascorbic Acid; Caspase 3; Endosulfan; Hemorrhage; Immunohistochemistry; Inflammation; Lymphocytes; Necrosis; Neutrophil Infiltration; Pesticides; Rabbits; Spleen

Pharmacological concentrations of small molecule natural products, such as ascorbic acid, have exhibited distinct cell killing outcomes between cancer and normal cells whereby cancer cells undergo apoptosis or necrosis while normal cells are not adversely affected. Here, we develop a mathematical model for ascorbic acid that can be utilized as a tool to understand the dynamics of reactive oxygen species (ROS) induced cell death. We determine that not only do endogenous antioxidants such as catalase contribute to ROS-induced cell death, but also cell membrane properties play a critical role in the efficacy of ROS as a cytotoxic mechanism against cancer cells vs. normal cells. Using in vitro assays with breast cancer cells, we have confirmed that cell membrane properties are essential for ROS, in the form of hydrogen peroxide (H2O2), to induce cell death. Interestingly, we did not observe any correlation between intracellular H2O2 and cell survival, suggesting that cell death by H2O2 is triggered by interaction with the cell membrane and not necessarily due to intracellular levels of H2O2. These findings provide a putative mechanistic explanation for the efficacy and selectivity of therapies such as ascorbic acid that rely on ROS-induced cell death for their anti-tumor properties.

Topics: Antineoplastic Agents; Antioxidants; Apoptosis; Ascorbic Acid; Breast Neoplasms; Catalase; Cell Death; Cell Line, Tumor; Cell Membrane; Cell Survival; Female; Humans; Hydrogen Peroxide; Models, Theoretical; Necrosis; Reactive Oxygen Species

Endosulfan is an insecticide that is composed of two stereoisomers: α- and β- endosulfan in an approximate ratio of 70:30. Owing to its widespread use, poisoning of both humans and animals is possible. We examined the toxic effects of endosulfan on New Zealand white rabbit kidneys. Rabbit kidneys were examined histopathologically and caspase-3 activity was detected using immunohistochemistry. Animals were divided into four groups: Group 1 was given a sublethal dose of endosulfan in corn oil by oral gavage daily for 6 weeks, Group 2 was given endosulfan + vitamin C during the same period, Group 3 was given corn oil daily and vitamin C on alternate days, Group 4 was given only corn oil daily throughout the experiment. By the end of experimental period, the concentration of α-endosulfan was greater than the β-endosulfan concentration in the kidneys of both of endosulfan treated groups (Groups 1 and 2). Decreased accumulation of α- and β-endosulfan was observed in Group 2, possibly because of the antioxidant effect of the vitamin C. Histopathological examination revealed hemorrhages, tubule cell necrosis, glomerular infiltration, glomerulosclerosis and proteinaceous material in the tubules, and Bowman spaces in the kidneys of Group 1. Caspase-3 reaction was stronger in Group 1 than in the other groups. Apoptotic activity was most frequent in proximal tubule cells. Endosulfan is toxic to rabbit kidneys. Vitamin C treatment reduced the accumulation of endosulfan in kidneys and reduced its toxicity.

Topics: Animals; Antioxidants; Apoptosis; Ascorbic Acid; Caspase 3; Endosulfan; Insecticides; Kidney; Kidney Diseases; Male; Necrosis; Rabbits

Human mesenchymal stem cells (hMSCs) contribute to ischemic tissue repair, regeneration, and possess ability to self-renew. However, poor viability of transplanted hMSCs within ischemic tissues has limited its therapeutic efficiency. Therefore, it is urgent to explore new method to improve the viability of the grafted cells. By using a systematic analysis, we reveal the mechanism of synergistic protection of N-acetylcysteine (NAC) and ascorbic acid 2-phosphate (AAP) on hMSCs that were under H2O2-induced oxidative stress. The combined treatment of NAC and AAP (NAC/AAP) reduces reactive oxygen species (ROS) generation, stabilizes mitochondrial membrane potential and decreases mitochondrial fission/fragmentation due to oxidative stress. Mitochondrial fission/fragmentation is a major prologue of mitoptosis. NAC/AAP prevents apoptotic cell death via decreasing the activation of BAX, increasing the expression of BCL2, and reducing cytochrome c release from mitochondria that might lead to the activation of caspase cascade. Stabilization of mitochondria also prevents the release of AIF, and its nuclear translocation which may activate necroptosis via H2AX pathway. The decreasing of mitoptosis is further studied by MicroP image analysis, and is associated with decreased activation of Drp1. In conclusion, NAC/AAP protects mitochondria from H2O2-induced oxidative stress and rescues hMSCs from mitoptosis, necroptosis and apoptosis.

Topics: Acetylcysteine; Apoptosis; Apoptosis Inducing Factor; Ascorbic Acid; bcl-2-Associated X Protein; Cell Proliferation; Cells, Cultured; Cytochromes c; Drug Synergism; Dynamins; GTP Phosphohydrolases; Histones; Humans; Hydrogen Peroxide; Mesenchymal Stem Cells; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Proteins; Necrosis; Oxidative Stress; Protective Agents; Proto-Oncogene Proteins c-bcl-2

Free radicals are chemicals that play roles in the etio-pathogenesis of ischaemia-reperfusion injury. Various antioxidants have been used in an attempt to mitigate the damage induced by these chemicals. In the present study, the antioxidative effects of grape seed extract (proanthocyanidin), tomato extract (lycopene), and vitamin C (ascorbic acid) on a composite re-established-flow inferior epigastric artery based rectus abdominis muscle-skin flap model on which experimental ischaemia was induced were investigated. The rats have been administered antioxidants for 2 weeks prior to the surgery and for 2 more weeks thereafter. Macroscopic, histopathological, and biochemical analyses were carried out at the decision of the experiment. It was found that flap skin island necrosis was significantly reduced in the proanthocyanidin, lycopene, vitamin C groups (p < 0.001). Statistical analyses showed significant decreases in inflammation, oedema, congestion, and granulation tissue in the proanthocyanidin and lycopene groups compared to the vitamin C and control groups (p < 0.001). When the viability rates of fat and muscle tissues were examined, significant improvements were found in the proanthocyanidin and lycopene groups in comparison to the other groups (p < 0.001). Serum antioxidant capacity measurements revealed significant differences in the lycopene group compared to all other groups (p < 0.001). It is concluded that lycopene and proanthocyanidin are protective antioxidants in rat composite muscle-skin flap ischaemia-reperfusion models.

Topics: Animals; Antioxidants; Ascorbic Acid; Carotenoids; Composite Tissue Allografts; Grape Seed Extract; Lycopene; Male; Necrosis; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Surgical Flaps

Irinotecan is one of the camptothecin analog which has been shown to have a broad spectrum of antitumor activities against various malignancies. The aim of this study was to evaluate the effect of vitamin A, C, E and melatonin on proapoptotic activity of irinotecan in human cancer cells in vitro. We observed that irinotecan induced apoptosis in all types of analyzed cell lines when used as a single agent. Combination of selected antioxidants with various doses of irinotecan (7.5-60μM) resulted in significant increase in apoptotic cell death in A549 and HT29 cancer cell lines. The highest killing efficiency was observed after co-incubation of the cells with irinotecan and vitamin A (10μM), or vitamin E (25μM), respectively. The addition of vitamin C and melatonin to irinotecan treatment did not promote increase in killing of cancer cells. Our results indicate that some antioxidants can enhance the proapoptoic activity (properties) of irinotecan in human cancer cells in vitro. These findings may be supportive for the optimization of therapeutic efficacy of irinotecan treatment.

Topics: Antineoplastic Agents, Phytogenic; Antioxidants; Apoptosis; Ascorbic Acid; Camptothecin; Cell Line, Tumor; Coloring Agents; Flow Cytometry; HT29 Cells; Humans; In Situ Nick-End Labeling; Irinotecan; Melatonin; Necrosis; Vitamin A; Vitamin E

The increased accessibility of antiretroviral therapy continues to positively drive the reduction in viral load and survival of patients despite the attendant reproductive toxicities. We propose that testicular damage caused by highly active antiretroviral therapy (HAART) can be attenuated by antioxidant treatment by investigating the testicular histomorphologic and stereological effects of antiretroviral drugs and its interaction with antioxidants using an experimental animal model. Sprague-Dawley rats were divided into seven groups of six rats per group (A, B... G) using simple random sampling and treated orally with 0.9% normal saline as placebo, a HAART cocktail of stavudine, lamivudine and nevirapine using the adjusted human therapeutic doses of 200, 600 and 350-400 mg/day, respectively, and antioxidants ascorbic acid (vitamin C) and I.M α-tocopherol (vitamin E). Animals were killed after 4 weeks and testicular tissue harvested and processed for light microscopy and stereological evaluations. The results were interpreted by a Veterinary pathologist blinded to the study. No animal died during the experimental period. The histopathological assessment of the testis of animals treated with placebo, ascorbic acid alone and α-tocopherol alone as well as vitamin E + HAART displayed normal testicular microanatomy. Groups treated with HAART alone, HAART + vitamin C + vitamin E and vitamins C + HAART showed extensive seminiferous tubular atrophy, necrosis and hypocellularity in the histoarchitectural patterns. While testicular cross-sectional area of seminiferous tubules remained unaffected by HAART, epithelial heights significantly decreased (p < 0.05) when compared with controls. There was marked (p < 0.05) increased in testicular-body weight ratio in HAART group. The results show that vitamin E could be useful in protecting testicular tissue from toxicities of HAART regimes as these results mirrors stereological data for the groups. HAART presents with deleterious histopathological changes in the testes causing tubular atrophy with altered morphometric indices. Supplementation with vitamin E appears to be a better adjuvant antioxidant that ameliorates these deleterious effects.

Topics: alpha-Tocopherol; Animals; Anti-HIV Agents; Antioxidants; Antiretroviral Therapy, Highly Active; Ascorbic Acid; Atrophy; Lamivudine; Male; Models, Animal; Necrosis; Nevirapine; Random Allocation; Rats; Rats, Sprague-Dawley; Seminiferous Tubules; Stavudine

Quinone-containing molecules have been developed against cancer mainly for their redox cycling ability leading to reactive oxygen species (ROS) formation. We have previously shown that donor-acceptor phenylaminonaphthoquinones are biologically active against a panel of cancer cells. In this report, we explored the mechanisms involved in cancer cell growth inhibition caused by two phenylaminonaphthoquinones, namely Q7 and Q9, with or without ascorbate (ASC). The results show that Q7 and Q9 are both redox cyclers able to form ROS, which strongly inhibit the proliferation of T24 cells. Q9 was a better redox cycler than Q7 because of marked stabilization of the semiquinone radical species arising from its reduction by ascorbate. Indeed, ASC dramatically enhances the inhibitory effect of Q9 on cell proliferation. Q9 plus ASC impairs the cell cycle, causing a decrease in the number of cells in the G2/M phase without involving other cell cycle regulating key proteins. Moreover, Q9 plus ASC influences the MAPK signaling pathways, provoking the appearance of a senescent cancer cell phenotype and ultimately leading to necrotic-like cell death. Because cellular senescence limits the replicative capacity of cells, our results suggest that induction of senescence may be exploited as a basis for new approaches to cancer therapy.

Topics: Aminophenols; Aniline Compounds; Antineoplastic Agents; Ascorbic Acid; Caspase 3; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cellular Senescence; Drug Synergism; Humans; Imidazoles; MAP Kinase Signaling System; Naphthoquinones; Necrosis; Oxidation-Reduction; Phenotype; Pyridines; Reactive Oxygen Species; Urinary Bladder Neoplasms

We hypothesized that zebrafish (Danio rerio) undergoing long-term vitamin E deficiency with marginal vitamin C status would develop myopathy resulting in impaired swimming. Zebrafish were fed for 1 y a defined diet without (E-) and with (E+) vitamin E (500 mg α-tocopherol/kg diet). For the last 150 days, dietary ascorbic acid concentrations were decreased from 3500 to 50 mg/kg diet and the fish sampled periodically to assess ascorbic acid concentrations. The ascorbic acid depletion curves were faster in the E- compared with E+ fish (P < 0.0001); the estimated half-life of depletion in the E- fish was 34 days, while in it was 55 days in the E+ fish. To assess swimming behavior, zebrafish were monitored individually following a "startle-response" stimulus, using computer and video technology. Muscle histopathology was assessed using hematoxylin and eosin staining on paramedian sections of fixed zebrafish. At study end, E- fish contained 300-fold less α-tocopherol (p < 0.0001), half the ascorbic acid (p = 0.0001) and 3-fold more malondialdehyde (p = 0.0005) than did E+ fish. During the first minute following a tap stimulus (p < 0.05), E+ fish swam twice as far as did E- fish. In the E- fish, the sluggish behavior was associated with a multifocal, polyphasic, degenerative myopathy of the skeletal muscle. The myopathy severity ranged from scattered acute necrosis to widespread fibrosis and was accompanied by increased anti-hydroxynonenal staining. Thus, vitamin E deficiency in zebrafish causes increased oxidative stress and a secondary depletion of ascorbic acid, resulting in severe damage to muscle tissue and impaired muscle function.

Topics: alpha-Tocopherol; Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Behavior, Animal; Fibrosis; Half-Life; Malondialdehyde; Muscle, Skeletal; Muscular Diseases; Necrosis; Oxidative Stress; Severity of Illness Index; Swimming; Vitamin E Deficiency; Zebrafish

Cardiovascular disease is one of the most significant causes of mortality in humans and animals, and its etiology is usually unknown. The aim of this study was to investigate the cardiac pathology of endosulfan toxicity and the protective effect of vitamin C in rabbits. Twenty-four rabbits were divided into 4 groups: (1) the END group was given a daily sublethal dose of endosulfan in corn oil by oral gavage for 6 weeks; (2) the END + C group received the endosulfan as well as vitamin C over the same 6-week period; (3) the OIL + C group received corn oil daily and vitamin C every other day; and (4) the OIL group received only corn oil daily. We observed microscopic hemorrhages, single-cell necrosis, inflammatory reactions, and fibrotic changes in the myocardium in the END group. Small hemorrhages and single-cell necrosis also were seen in some hearts in the END + C group, but no inflammation was observed. Caspase-3 immunoreactivity was more significant in myocardial cells in the END group compared with the others. A protective effect of vitamin C on lesions was observed in the END + C group. These results showed that endosulfan resulted in toxic changes in the hearts of rabbits, but this toxicity could be decreased with vitamin C treatment.

Topics: Administration, Oral; Animals; Apoptosis; Ascorbic Acid; Cardiotoxins; Caspase 3; Disease Models, Animal; Dose-Response Relationship, Drug; Endosulfan; Fibrosis; Heart Diseases; Insecticides; Male; Myocytes, Cardiac; Necrosis; Rabbits

Hyperglycemia leads to the formation of free radicals and advanced glycation end-products (AGEs). Antioxidants can reduce the level of protein glycation and DNA damage. In this study, we compared the levels of vitamin C intake, which is among the most abundant antioxidants obtained from diet, with the levels of fasting plasma glucose (FPG), glycated hemoglobin (A1C), DNA damage, and cytotoxicity in prediabetic subjects and type 2 diabetic subjects. Our results indicated that there was no significant correlation between FPG or A1C and DNA damage parameters (micronuclei, nucleoplasmic bridges, and nuclear buds). FPG and A1C correlated with necrosis (r = 0.294; P = 0.013 and r = 0.401; P = 0.001, resp.). Vitamin C intake correlated negatively with necrosis and apoptosis (r = -0.246; P = 0.040, and r = -0.276; P = 0.021, resp.). The lack of a correlation between the FPG and A1C and DNA damage could be explained, at least in part, by the elimination of cells with DNA damage by either necrosis or apoptosis (cytotoxicity). Vitamin C appeared to improve cell survival by reducing cytotoxicity. Therefore, the present results indicate the need for clinical studies to evaluate the effect of low-dose vitamin C supplementation in type 2 diabetes.

Topics: Adult; Apoptosis; Ascorbic Acid; Blood Glucose; Cohort Studies; Diabetes Mellitus, Type 2; Dietary Supplements; Glycated Hemoglobin; Humans; Hyperglycemia; Male; Middle Aged; Necrosis; Prediabetic State

Pancreatic cancer cell lines with mutated ras underwent an alternative form of cell death (aponecrosis) when treated concomitantly with clinically achievable concentrations of arsenic trioxide, ascorbic acid, and disulfiram (Antabuse; AAA). AAA's major effects are mediated through generation of intracellular reactive oxygen species (ROS) and more than 50% decline in intracellular ATP. N-acetyl cysteine and a superoxide dismutase mimetic prevented aponecrosis and restored intracellular ATP levels. DIDS (4,4'-diisothiocyanatostilbene-2, 2' disulfonic acid), the pan- Voltage-Dependent Anion Channel (VDAC), -1, 2, 3 inhibitor and short hairpin RNA (shRNA) to VDAC-1 blocked cell death and ROS accumulation. In vivo exposure of AAA led to a 62% reduction in mean tumor size and eliminated tumors in 30% of nude mice with PANC-1 xenografts. We concluded that early caspase-independent apoptosis was shifted to VDAC-mediated "targeted" aponecrosis by the addition of disulfiram to arsenic trioxide and ascorbic acid. Conceptually, this work represents a paradigm shift where switching from apoptosis to aponecrosis death pathways, also known as targeted aponecrosis, could be utilized to selectively kill pancreatic cancer cells resistant to apoptosis.

Topics: Adenosine Triphosphate; Animals; Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Cell Line, Tumor; Disease Models, Animal; Disulfiram; Dose-Response Relationship, Drug; Heterografts; Humans; Male; Mice; Necrosis; Oxides; Pancreatic Neoplasms; Reactive Oxygen Species; Tumor Stem Cell Assay; Voltage-Dependent Anion Channels

Since gentamicin-induced nephrotoxicity has very important clinical consequences, different potentially therapeutic approaches to prevent or attenuate it have been proposed. Accordingly, this study aimed at determining the possible protective effects of vitamin C against gentamicin-associated acute kidney injury. Experiments were done on 40 adult Wistar rats divided into four groups of 10 animals each. G-group received gentamicin (100 mg/kg) while GVC-group received the same dose of gentamicin and vitamin C (200 mg/kg) by intraperitoneal injections on a daily basis. Animals in VC-group, serving as a positive control, received only vitamin C (200 mg/kg), and those in C-group, serving as a negative control, received saline (1 ml/day), both given intraperitoneally. All groups were treated during 8 consecutive days. Quantitative evaluation of gentamicin-induced structural alterations and degree of functional alterations of kidney were performed by histopathological, morphometrical and biochemical analyses in order to determine potential beneficial effects of vitamin C co-administration with gentamicin. In G-group the proximal convoluted tubules showed cytoplasm vacuolation with dark inclusions in the epithelial cells and coagulation-type necrosis, while in GVC-group necrosis was not observed. The glomerular basement membrane was significantly thickened (p<0.05) in G-group animals than in other groups. Nuclear optical density of the tubular epithelial cells in GVC-group was significantly higher (p<0.05) compared to G-group. Blood urea and serum creatinine concentration were significantly elevated, while potassium concentration was lowered in G-group compared to other groups (p<0.01 for each). Concomitant administration of gentamicin and vitamin C resulted in a significant reduction of morphological and functional kidney alterations.

Topics: Acute Kidney Injury; Animals; Anti-Bacterial Agents; Antioxidants; Ascorbic Acid; Cell Nucleus; Cytoprotection; Epithelial Cells; Female; Gentamicins; Kidney Tubules, Distal; Kidney Tubules, Proximal; Male; Necrosis; Oxidative Stress; Rats; Rats, Wistar; Reactive Oxygen Species

Several phenylaminopyrimidoisoquinolinequinones (APIQs) were tested for their cytotoxicity against different cancer cell lines (K562, T24, HepG2) in the presence or absence of ascorbate. Ascorbate enhanced the toxic effects of quinones with first half-wave potential E(I) (1/2) values in the range of -480 to -660 mV. Phenylaminoquinones that were unsubstituted at position 6 exhibited greater cytotoxic activity than did their 6-methyl-substituted analogues. Two groups of compounds were further selected, namely 8-10 and 20-22, to study the cellular mechanisms involved in quinone cytotoxicity. Indeed, these compounds have the same range of redox potentials but differed considerably in their capacity to induce cell death. In the presence of ascorbate, the cell demise induced by compounds 8-10 was not caspase-3 dependent, as shown by the lack of activation of caspase-3 and the absence of cleaved PARP fragments. In addition, an index of ER stress (eIF2α phosphorylation) was activated by these compounds. Quinones 8-10 decreased the cellular capacity to reduce MTT dye and caused marked ATP depletion. Taken together, our results show that ascorbate enhances quinone redox-cycling and leads to ROS formation that inhibits cell proliferation and provokes caspase-independent cell death. Interestingly, we also observed that quinone 8 had a rather selective effect given that freshly isolated peripheral blood leukocytes from human healthy donors were more resistant than human leukemia K562 cells.

Topics: Adult; Ascorbic Acid; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cells, Cultured; Cytostatic Agents; Female; Humans; L-Lactate Dehydrogenase; Leukocytes; Male; Middle Aged; Necrosis; Neoplasms; Oxidation-Reduction; Oxidative Stress; Poly(ADP-ribose) Polymerases; Quinolones; Reactive Oxygen Species

Oxidative stress contributes to myonecrosis in the dystrophin-deficient fibers of mdx mice and in Duchenne's muscular dystrophy. We examined the effects of ascorbic acid (AA), an antioxidant and free radical scavenger, on the dystrophic diaphragm muscle.. Mdx mice (14 d old) received AA for 14 d. Control mdx mice received saline. The muscle damage was visualized by the penetration of Evans blue dye into myofibers and the extent of inflammation was assessed by histologic analysis. Creatine kinase levels were measured for the biochemical evaluation of muscle fiber degeneration. The levels of tumor necrosis factor-α (a proinflammatory cytokine) and 4-hydroxynonenal (a marker of lipid peroxidation) were analyzed by immunoblotting.. Ascorbic acid decreased creatine kinase levels, myonecrosis, inflammation, and the levels of tumor necrosis factor-α and 4-hydroxynonenal.. The present results suggest that AA plays a protective role in dystrophic muscle degeneration, possibly by decreasing reactive oxygen species, and support further investigations of AA as a potential therapy for dystrophinopathies.

Topics: Aldehydes; Animals; Antioxidants; Ascorbic Acid; Creatine Kinase; Diaphragm; Dystrophin; Female; Inflammation; Male; Mice; Mice, Inbred mdx; Muscle Fibers, Skeletal; Muscular Dystrophies; Necrosis; Oxidative Stress; Reactive Oxygen Species; Tumor Necrosis Factor-alpha

Nitric oxide (NO) derived from endothelial nitric oxide synthase (eNOS) is a potent vasodilator and signaling molecule that plays an essential role in vascular remodeling of collateral arteries and perfusion recovery in response to hindlimb ischemia. In ischemic conditions, decreased NO bioavailability was observed because of increased oxidative stress, decreased L-arginine and tetrahydrobiopterin. This study tested the hypothesis that dietary cosupplementation with tetrahydrobiopterin (BH4), L-arginine, and vitamin C acts synergistically to decrease oxidative stress, increase nitric oxide and improve blood flow in response to acute hindlimb ischemia. Rats were fed normal chow, chow supplemented with BH4 or L-arginine (alone or in combination) or chow supplemented with BH4 + L-arginine + vitamin C for 1 wk before induction of unilateral hindlimb ischemia. Cosupplementation with BH4 + L-arginine resulted in greater eNOS expression, Ca²⁺-dependent NOS activity and NO concentration in gastrocnemius from the ischemic hindlimb, as well as greater recovery of foot perfusion and more collateral artery enlargement than did rats receiving either agent separately. The addition of vitamin C to the BH4 + L-arginine regimen did further increase these dependent variables, although only the increase in eNOS expression reached statistical significances. In addition, rats given all three supplements demonstrated significantly less Ca²⁺-independent activity, less nitrotyrosine accumulation, greater glutathione:glutathione disulfide (GSH:GSSG) ratio and less gastrocnemius muscle necrosis, on both macroscopic and microscopic levels. In conclusion, cosupplementation with BH4 + L-arginine + vitamin C significantly increased vascular perfusion after hindlimb ischemia by increasing eNOS activity and reducing oxidative stress and tissue necrosis. Oral cosupplementation of L-arginine, BH4 and vitamin C holds promise as a biological therapy to induce collateral artery enlargement.

Topics: Administration, Oral; Animals; Antioxidants; Arginine; Ascorbic Acid; Biopterins; Calcium; Drug Synergism; Enzyme Activation; Hindlimb; Ischemia; Male; Muscle, Skeletal; Necrosis; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Rats; Rats, Sprague-Dawley; Regional Blood Flow

We studied the mechanism of ascorbate toxicity in malignant mesothelioma (MMe) cells. Neutral red uptake showed that ascorbate, but not dehydroascorbate, was highly toxic in the MMe cell lines REN and MM98, and less toxic in immortalized (human mesothelial cells-htert) and primary mesothelial cells. Ascorbate transport inhibitors phloretin, sodium azide, and ouabain did not reduce ascorbate toxicity. Ascorbate promoted the formation of H(2)O(2) in the cell medium, and its toxicity was suppressed by extracellular catalase, but the concentration of endogenous catalase was higher in MMe cells than in normal cells. The confocal imaging of cells loaded with the dihydrhodamine 123 reactive oxygen species probe showed that ascorbate caused a strong increase of rhodamine fluorescence in MMe cells, but not in mesothelial cells. MMe cells showed a higher production of superoxide and NADPH oxidase (NOX)4 expression than did mesothelial cells. Two inhibitors of cellular superoxide sources (apocynin and rotenone) reduced ascorbate toxicity and the ascorbate-induced rise in rhodamine fluorescence. NOX4 small interfering RNA also reduced ascorbate toxicity in REN cells. Taken together, the data indicate that ascorbate-induced extracellular H(2)O(2) production induces a strong oxidative stress in MMe cells because of their high rate of superoxide production. This explains the selective toxicity of ascorbate in MMe cells, and suggests its possible use in the clinical treatment of malignant mesothelioma.

Topics: Antineoplastic Agents; Apoptosis; Ascorbic Acid; Catalase; Cell Line, Tumor; Dose-Response Relationship, Drug; Glucose Transporter Type 1; Humans; Hydrogen Peroxide; Inhibitory Concentration 50; Mesothelioma; Microscopy, Confocal; Mutation; NADPH Oxidase 4; NADPH Oxidases; Necrosis; Organic Anion Transporters, Sodium-Dependent; Ouabain; Oxidation-Reduction; Oxidative Stress; Phloretin; RNA Interference; Sodium Azide; Superoxides; Symporters; Tumor Suppressor Protein p53

Recent studies have demonstrated that vegetable rich diets have protective effects on the occurrence and prognosis of various cancers. In addition to dietary intakes, ascorbic acid and β-carotene are also taken as supplements. The aim of this study was to assess effects of ascorbic acid, β-carotene and their combinations on human hepatocellular carcinoma cell line HepG2. Ascorbic acid and β-carotene were applied to cells as plasma peak concentrations (70 and 8 μM, respectively) and their half concentrations (35 and 4 μM, respectively) for 24 and 48 h. Genotoxic and cytotoxic effects of ascorbic acid and β-carotene were evaluated by alkali single cell gel electrophoresis (SCGE), acridine orange/ethidium bromide staining patterns of cells (apoptosis and necrosis) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Results of the SCGE demonstrated that both ascorbic acid and β-carotene caused DNA damage on HepG2 which were also concordant to increased apoptosis and necrosis of cells. Increased TBARS values also demonstrated increased lipid peroxidation in these cells. Results of the present study demonstrates that when dietary intakes of ascorbic acid and β-carotene and their relevant achievable plasma level concentrations were considered, both ascorbic acid and β-carotene induce genotoxic and cytotoxic damage on HepG2 together with increased oxidative damage in contrast to their protective effect on healthy cells. This may be correlated to oxidative status and balance of ROS in hepatocellular carcinoma cells.

Topics: Acridine Orange; Apoptosis; Ascorbic Acid; beta Carotene; Carcinoma, Hepatocellular; Cell Line, Tumor; Comet Assay; DNA Damage; Ethidium; Genome, Human; Hep G2 Cells; Humans; Lipid Peroxidation; Liver Neoplasms; Necrosis; Staining and Labeling; Thiobarbituric Acid Reactive Substances

Cancer cells generally exhibit high levels of reactive oxygen species (ROS) that stimulate cell proliferation and promote genetic instability. Since this biochemical difference between normal and cancer cells represents a specific vulnerability that can be selectively targeted for cancer therapy, various ROS-generating agents are currently in clinical trials, either as single agents or in combination with standard therapy. However, little is known about the potential consequences of an increased oxidative stress for the efficacy of standard chemotherapeutic agents. In this context, we have assessed the influence of an oxidative stress generated by the combination of ascorbate and the redox-active quinone menadione on the capacity of melphalan, a common alkylating agent, to induce apoptosis in a chronic myelogenous leukemia cell line. Our data show that oxidative stress did not inhibit but rather promoted cancer cell killing by melphalan. Interestingly, we observed that, in the presence of oxidative stress, the type of cell death shifted from a caspase-3 dependent apoptosis to necrosis because of an ATP depletion which prevented caspase activation. Taken together, these data suggest that ROS-generating agents could be useful in combination with standard chemotherapy, even if all the molecular consequences of such an addition remain to be determined.

Topics: Adenosine Triphosphate; Antineoplastic Agents; Antineoplastic Agents, Alkylating; Apoptosis; Ascorbic Acid; Caspase 3; Drug Interactions; Humans; K562 Cells; Melphalan; Necrosis; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species; Vitamin K 3

To explore the efficacy of n-hexane extract of Emilia sonchifolia (E. sonchifobia) against ethanol induced pancreatic dysfunction in the young Wistar albino rats.. The rats were divided into four groups. Control rats in group received distilled water orally, group received oral administration of 20% (w/v) ethanol dissolved in drinking water, group received oral administration of 20% (w/v) ethanol in distilled water+n-hexane extract of E. sonchifolia (250 mg/kg body weight), and group received oral administration of n-hexane extract of E. sonchifolia (250 mg/kg body weight) alone. Liver marker enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), pancreatic enzymatic antioxidants superoxide dismutase, lipid peroxidation, catalase, glutathione peroxidase, non-enzymatic antioxidants glutathione and vitamin C were measured and compared.. Administration of 20% ethanol for 16 weeks significantly increased the liver marker enzymes AST, ALT(P<0.05), reduced the pancreatic enzymatic antioxidants superoxide dismutase, lipid peroxidation, catalase, glutathione peroxidase, glutathione and vitamin C(P<0.05). Histopathological examination showed that the ethanol provoked the oxidative stress which was demonstrated as pancreatic necrosis and oedema. Simultaneous administration of n-hexane extract of E. sonchifolia (250 mg/kg body weight) protected the pancreas against the damage induced by ethanol which was confirmed by the histopathological studies and the normalization of biochemical parameters.. Thus n-hexane extract of E. sonchifolia shows a promise in therapeutic use in alcohol induced oxidative stress.

Topics: Alanine Transaminase; Animals; Antioxidants; Ascorbic Acid; Catalase; Edema; Ethanol; Glutathione; Glutathione Peroxidase; Lipid Peroxidation; Liver; Male; Necrosis; Oxidative Stress; Pancreas; Phytotherapy; Plant Extracts; Rats; Rats, Wistar; Sonchus; Superoxide Dismutase

Pancreas pathology in subacute endosulfan toxicity and the effect of vitamin C in rabbits were studied.. : Twenty-four rabbits in 4 groups were used. The rabbits in group END were given a daily sublethal dose (1 mg/kg of body weight) of endosulfan in corn oil by oral gavage for 6 weeks. Group END+C received the same dose of endosulfan and also vitamin C (20 mg/kg) every other day. Group OIL+C received oral corn oil daily and vitamin C (20 mg/kg) every other day. Group OIL received corn oil daily by oral gavage throughout the experiment. Serum amylase, lipase, and glucose levels were analyzed 1 week after the last treatment. Histopathological and immunohistochemical methods were used.. The amylase levels were normal, but the lipase levels were increased in all the groups. Marked increases in glucose levels were observed in the END and the OIL+C groups. Microscopy examination of the pancreases indicated degenerative changes in the END group. The pancreases of the END+C group were relatively normal in appearance. The immunohistochemistry of the pancreas showed marked decreases in proinsulin-, insulin-, and amylin-secreting cells and slight decreases in glucagon-secreting cells, whereas cells expressing caspase 3 increased.. Endosulfan can cause toxic effects on rabbit pancreases, but vitamin C has an ameliorative effect.

Topics: Amylases; Animals; Ascorbic Acid; Blood Glucose; Caspase 3; Endosulfan; Glucagon-Secreting Cells; Immunohistochemistry; Insecticides; Insulin-Secreting Cells; Lipase; Male; Necrosis; Pancreas; Rabbits

CCl(4) (0.5 ml/kg as CCl(4)) was orally administered to rats. Twelve hours after administration of CCl(4), plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, indicators of liver necrosis, were significantly higher than those in the control group showing that active liver necrosis took place. At the same time the level of liver vitamin C was decreased significantly compared to that in the control group. Oral administration of 100 mg/kg each of celecoxib 3 and 8 h after CCl(4) treatment did not change plasma ALT and AST and liver vitamin C levels 12 h after CCl(4) treatment, but 24 h after CCl(4) treatment, significantly decreased plasma ALT and AST levels and elevated liver vitamin C level. These finding suggested that celecoxib effectively ameliorated the necrotic action and the oxidative stress induced by CCl(4) in the second phase. Although the plasma levels of all ceramide species were significantly increased 24 h after CCl(4) intoxication, treatment with celecoxib significantly reduced the total ceramide concentration in plasma. These results indicated that celecoxib significantly ameliorated the toxicity of CCl(4) in the second phase.

Topics: Alanine Transaminase; Animals; Antioxidants; Ascorbic Acid; Aspartate Aminotransferases; Carbon Tetrachloride Poisoning; Celecoxib; Ceramides; Chemical and Drug Induced Liver Injury; Cyclooxygenase 2 Inhibitors; Liver; Male; Necrosis; Oxidative Stress; Pyrazoles; Rats; Rats, Wistar; Sulfonamides

Iron chelators and antioxidants have been shown to prevent hypothermia-induced apoptosis in hepatocytes. This study examined whether iron chelation and antioxidants could also prevent hypothermia-induced necrosis. Isolated rat hepatocytes were incubated at 4 degrees C for 6 hours and then rewarmed at 37 degrees C for 18 hours with or without the iron chelator deferoxamine and a selection of antioxidants. There was no evidence of increased cell death or adenosine triphosphate depletion during hypothermic incubation. After hypothermia and rewarming, the majority of rat hepatocytes died of necrosis as indicated by the absence of DNA fragmentation, caspase 3 activity, and apoptotic bodies. Cell death was significantly reduced if deferoxamine or a selection of antioxidants were present during hypothermia and rewarming. Deferoxamine was more effective in preventing cell death when added prior to hypothermia, indicating cell death processes were likely initiated during hypothermia.

Topics: Adenosine Triphosphate; Animals; Apoptosis; Ascorbic Acid; Caspase 3; Cell Culture Techniques; Cell Death; Hepatocytes; Hypothermia; Iron; L-Lactate Dehydrogenase; Lactates; Necrosis; Oxidative Stress; Rats

Ascorbic acid (AA) is a potent antioxidant, and its neuroprotective effect has not been established yet. Using the Rice-Vannucci model, we examined the effect of AA on hypoxic-ischemic (HI) injury in the immature rat brain. Under isoflurane anesthesia, 7-day-old rat pups received 750 mg/kg of AA by intraperitoneal injection just before hypoxic exposure; 8% oxygen for 90 min. Vehicle controls received an equal volume of saline. AA decreased a macroscopic brain injury score at 48 and 168 h post-HI compared with vehicle controls (48 h post-HI, AA 1.38+/-0.45 vs. controls 2.94+/-0.24, p<0.05; 168 h post-HI, 1.13+/-0.44 vs. 2.50+/-0.25, p<0.05). AA injection significantly decreased the number of both necrotic and apoptotic cells in cortex, caudate putamen, thalamus and hippocampus, and also seemed to reduce the number of TUNEL-positive cells. Western blot analysis showed that AA significantly suppressed 150/145 kDa subunits of alpha-fodrin breakdown products (FBDP) in cortex, striatum, thalamus and hippocampus at 24 and 48 h post-HI, and also 120 kDa subunit of FBDP in all examined regions except for thalamus, which indicated that AA injection inhibited both calpain and caspase-3 activation. Western blot analysis of nitrotyrosine failed to show inhibition of free radical production by AA, however, our results show that AA inhibits both necrotic and apoptotic cell death and that AA is neuroprotective after HI in immature rat brain.

Topics: Analysis of Variance; Animals; Animals, Newborn; Antioxidants; Apoptosis; Ascorbic Acid; Blotting, Western; Brain; Brain Ischemia; Calpain; Carrier Proteins; Caspase 3; Enzyme Activation; In Situ Nick-End Labeling; Microfilament Proteins; Microscopy, Electron; Necrosis; Neurons; Neuroprotective Agents; Rats; Tyrosine

Carbon tetrachloride (1 ml/kg body weight as a 1:1 mixture of CCl(4) and mineral oil) was orally administered to rats. After 12 h, the activity of plasma ALT (alanine aminotransferase) was significantly higher than that of the control group, and plasma ALT and AST (aspartate aminotransferase) activities significantly increased 24 h after CCl(4) administration. These results indicated that the necrotic process had initiated at about 12 h and developed thereafter. After 6-24 h of CCl(4) administration, the hepatic level of vitamin C, the most sensitive indicator of oxidative stress, decreased significantly, indicating that oxidative stress was significantly enhanced 6 h after CCl(4) intoxication and thereafter. Oral administration of vitamin E (1 ml/kg body weight as a 1:1 mixture of alpha-tocopherol and mineral oil) 12 h before CCl(4) administration caused a significant elevation of liver vitamin E level and ameliorated liver necrosis 24 h after CCl(4) intoxication based on plasma AST and ALT. Vitamin E also significantly restored the hepatic vitamin C concentration 12 and 24 h after CCl(4) intoxication, demonstrating that vitamin E functioned as an antioxidant. The liver vitamin E concentration was not changed by vitamin E supplementation to rats that did not receive CCl(4). This result indicated that vitamin E accumulated in the damaged liver. The activation of JNK, ERK1/2 and p38 MAPK took place 1.5 h after CCl(4) administration. Co-administration of alpha-tocopherol with CCl(4) did not affect these early changes in MAPKs.

Topics: Alanine Transaminase; alpha-Tocopherol; Animals; Ascorbic Acid; Aspartate Aminotransferases; Carbon Tetrachloride Poisoning; Liver; Male; Necrosis; Rats; Rats, Wistar; Time Factors; Vitamin E

Preeclampsia is a pregnancy-specific disease characterised by maternal hypertension that is preceded by endothelial cell activation and an inappropriate inflammatory response. The exact cause of preeclampsia is unclear but this disease is known to be induced by a placental factor and it is hypothesised that oxidative stress may also contribute to its pathogenesis. We have shown that dead trophoblasts shed from the placenta can be phagocytosed by endothelial cells and that phagocytosis of necrotic, but not apoptotic, trophoblasts leads to endothelial cells activation. Since phagocytosis may be accompanied by an oxidative burst which may lead to damage/activation of the phagocyte, in this study we have investigated whether the antioxidant vitamin C can protect endothelial cells that phagocytose necrotic trophoblasts from activation. We demonstrate that treatment of phagocytosing endothelial cells with vitamin C induced an increase in the phagocytosis of necrotic trophoblasts but that activation of the phagocytosing endothelial cells was prevented. Treatment of phagocytosing endothelial cells with vitamin C also prevented the increase in IL-6 secretion that normally accompanies phagocytosis of necrotic trophoblasts. Thus treatment of endothelial cells with vitamin C appears to modify both the phagocytosis of necrotic trophoblasts and the response of the endothelial cells to the necrotic trophoblastic material.

Topics: Adult; Antioxidants; Ascorbic Acid; Cell Line, Tumor; Choriocarcinoma; Endothelial Cells; Female; Humans; Interleukin-6; Necrosis; Phagocytosis; Pre-Eclampsia; Pregnancy; Trophoblasts; Umbilical Veins; Young Adult

To study the therapeutic effect of intravenous high-dose vitamin C on implanted hepatoma in rats.. The rats bearing implanted Walker-256 hepatoma were treated with high-dose vitamin C at 2.83 and 5.65 g/kg intravenously, and the general condition, liver functions (A/G, ALT, AST, GGT), tumor volume, and tumor growth of the rats were evaluated.. The A/G of the rats treated with 2.83 g/kg vitamin C was significantly higher, but the ALT and GCT were significantly lower than those of the model rats (P<0.05 or 0.01). The ALT level in rats with 5.65 g/kg vitamin C treatment was significantly lower than that of the model rats (P<0.05). The tumor necrosis rate was significantly higher in rats with 2.83 g/kg vitamin C treatment than in the model rats (P<0.05).. Intravenous administration of 2.83 g/kg vitamin C can promote the necrosis and apoptosis of hepatoma Walker256 cells in rats and protect the liver function of the tumor-bearing rats.

Topics: Animals; Apoptosis; Ascorbic Acid; Injections, Intravenous; Liver Neoplasms, Experimental; Male; Necrosis; Neoplasm Transplantation; Rats; Rats, Sprague-Dawley; Rats, Wistar

Combined antioxidant deficiencies of selenium and vitamin E or vitamin E and vitamin C in guinea pigs result in clinical illness. We hypothesized that combined selenium and vitamin C deficiency would have clinical consequences because in vitro interactions of these antioxidant nutrients have been reported. Because guinea pigs are dependent on dietary vitamin C, weanling male guinea pigs were fed selenium-deficient or control diet for 15 weeks before imposing vitamin C deficiency. Four dietary groups were formed and studied 3 weeks later: controls, vitamin C deficient, selenium deficient, and doubly deficient. Deficiencies were confirmed by determinations of glutathione peroxidase activity and vitamin C concentration in liver and skeletal muscle. Plasma creatine phosphokinase activity and liver, kidney, heart, and quadriceps histopathology were determined. Doubly deficient animals had moderately severe skeletal muscle cell death as judged by histopathology and plasma creatine phosphokinase activity of 6630 +/- 4400 IU/L (control, 70 + or - 5; vitamin C deficient, 95 + or - 110; selenium deficient, 280 + or - 250). Liver, kidney, and heart histology was normal in all groups. Muscle alpha-tocopherol levels were not depressed in the doubly deficient group, but muscle F2 isoprostane concentrations were elevated in them and correlated with markers of cell death. We conclude that combining selenium and vitamin C deficiencies in the guinea pig causes cell death in skeletal muscle that is more severe than the injury caused by selenium deficiency. The elevation of muscle F2 isoprostanes is compatible with the cell death being caused by oxidative stress.

Topics: alpha-Tocopherol; Animals; Antioxidants; Ascorbic Acid; Ascorbic Acid Deficiency; Cell Death; Creatine Kinase; Diet; F2-Isoprostanes; Glutathione Peroxidase; Guinea Pigs; Lipid Peroxidation; Male; Muscle, Skeletal; Necrosis; Scurvy; Selenium

The major aims of this study were to investigate the effect of an Ironman triathlon on DNA migration in the single cell gel electrophoresis assay, apoptosis and necrosis in the cytokinesis-block micronucleus cytome assay with lymphocytes and on changes of total antioxidant capacity in plasma. Blood samples were taken 2 days (d) before, within 20 min, 1 d, 5 d and 19 d post-race. The level of strand breaks decreased (p<0.05) immediately after the race, then increased (p<0.01) 1 d post-race and declined (p<0.01) until 19 d post-race. Apoptotic and necrotic cells decreased (p<0.01) and the total antioxidant status increased (p<0.01) immediately after the race. The results indicate that ultra-endurance exercise does not cause prolonged DNA damage in well-trained male athletes.

Topics: Adult; alpha-Tocopherol; Antioxidants; Apoptosis; Ascorbic Acid; Bicycling; Carbon Dioxide; Competitive Behavior; DNA Damage; Exercise Test; Heart Rate; Humans; Lactates; Male; Necrosis; Oxidation-Reduction; Oxygen; Respiration; Running; Sampling Studies; Swimming

Artichoke is a plant with antioxidant properties. In this study, we investigated the effect of artichoke extract pretreatment on carbon tetrachloride (CCl4)-induced oxidative stress and hepatotoxicity. Rats were given artichoke leaf extract (1.5g/kg/day) by gavage for 2 weeks and after then CCl4 (1ml/kg; i.p.) was applied. All rats were killed 24h after the CCl4 injection. CCl4 administration resulted in hepatic necrosis and significant increases in plasma transaminase activities as well as hepatic malondialdehyde (MDA) and diene conjugate (DC) levels in the liver of rats. Glutathione (GSH) and vitamin C levels decreased, but vitamin E levels increased in the liver of CCl4-treated rats. Hepatic superoxide dismutase (SOD) activities remained unchanged, but glutathione peroxidase (GSH-Px) and glutathione transferase (GST) activities decreased following CCl4 treatment. In rats pretreated with artichoke extract, significant decreases in plasma transaminase activities and amelioration in histopathological changes in the liver were observed following CCl4 treatment as compared to CCl4-treated rats. In addition, hepatic MDA and DC levels decreased, but GSH levels and GSH-Px activities increased without any change in other antioxidant parameters following CCl4 treatment in artichoke-pretreated rats. The present findings indicate that in vivo architoke extract administration may be useful for the prevention of oxidative stress-induced hepatotoxicity.

Topics: Administration, Oral; Antioxidants; Ascorbic Acid; Carbon Tetrachloride; Cynara scolymus; Glutathione; Lipid Peroxidation; Liver; Liver Cirrhosis, Experimental; Malondialdehyde; Necrosis; Oxidative Stress; Oxidoreductases; Plant Extracts; Plant Leaves; Transaminases; Vitamin E

Experimental and clinical data indicate that 3,4-methylenedioxy-N-methylamphetamine (MDMA) abuse can produce significant cardiovascular toxicity. A mechanism may be a direct toxic effect of redox active metabolites of MDMA. To evaluate the effect of a single MDMA dose on cellular antioxidant defence system and to investigate the morphology in male albino rats, total glutathione (GSH), oxidised glutathione (GSSG), ascorbic acid (AA), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and malondialdehyde (MDAL) were studied. The effects were evaluated at 3, 6, 16 and 24 h after MDMA administration. Antioxidant enzymes activity was significantly reduced: GPx (-24%) and SOD (-50%) after 3 h and GR (-19%) after 6 h from treatment. AA levels decrease (-37%) after 3 h and (-30%) after 6 h; MDAL level increased (+119%) after 3 h; GSH levels decreased after 3 (31.3%) and 6 h (37.9%) from MDMA treatment. GSSG content was not affected by ecstasy administration. Myocardial contraction band necrosis (CBN) was already visible in rats killed at 6 h. After 16 h, macrophagic monocytes around the necrotic myocardial cells were observed, and within 24 h, this infiltrate became more widespread with an early removal of the necrotic material. Calcium deposits were observed within ventricular cardiomyocytes with intact nuclei and sarcomeres. Single administration of MDMA can significantly alter the cellular antioxidant defence system and produce oxidative stress which may result in lipid peroxidation and disruption of Ca(2 +) homeostasis. The depression in Ca(2+) regulatory mechanism by reactive oxygen species ultimately results in intracellular Ca(2 +) overload, CBN and cell death.

Topics: Animals; Ascorbic Acid; Calcinosis; Forensic Toxicology; Glutathione; Glutathione Disulfide; Glutathione Peroxidase; Glutathione Reductase; Hallucinogens; Macrophages; Male; Malondialdehyde; Microscopy, Confocal; Models, Animal; Myocardium; Myocytes, Cardiac; Myoglobin; N-Methyl-3,4-methylenedioxyamphetamine; Necrosis; Oxidative Stress; Rats; Superoxide Dismutase; Time Factors; Troponin C; Troponin I

THP-1 cell-derived foam cells were exposed to oxidative stress through combined treatment with acetylated LDL (acLDL) and copper ions (Cu2+). The foam cells showed caspase-dependent apoptotic changes on exposure to oxidative stress for 6 h, and necrotic changes with the leakage of LDH after 24 h. KY-455, an anti-oxidative ACAT inhibitor, and ascorbic acid (VC) but not YM-750, an ACAT inhibitor, prevented apoptotic and necrotic changes. These preventive effects of KY-455 and VC were accompanied by the inhibition of lipid peroxidation in culture medium containing acLDL and Cu2+, suggesting the involvement of oxidized acLDL in apoptosis and necrosis. Foam cells accumulated esterified cholesterol (EC) for 24 h in the presence of acLDL without Cu2+, which was suppressed by KY-455 and YM-750. Foam cells showed necrotic changes and died in the presence of acLDL and Cu2+. KY-455 but not YM-750 prevented cell death and reduced the amount of EC accumulated. The foam cells treated with VC further accumulated EC without necrotic changes for 24 h even in the presence of acLDL and Cu2+. YM-750 as well as KY-455 inhibited lipid accumulation when co-incubated with VC in foam cells exposed to oxidative stress. It is concluded that an anti-oxidative ACAT inhibitor or the combination of an antioxidant and an ACAT inhibitor protects foam cells from oxidative stress and effectively reduces cholesterol levels, which would be a promising approach in anti-atherosclerotic therapy.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Ascorbic Acid; Cell Line; Cholesterol; Copper Sulfate; Foam Cells; Indoles; Lipid Peroxidation; Lipoproteins, LDL; Necrosis; Oxidative Stress; Propane; Rabbits; Sterol O-Acyltransferase; Thiobarbituric Acid Reactive Substances

Among different features of cancer cells, two of them have retained our interest: their nearly universal glycolytic phenotype and their sensitivity towards an oxidative stress. Therefore, we took advantage of these features to develop an experimental approach by selectively exposing cancer cells to an oxidant insult induced by the combination of menadione (vitamin K(3)) and ascorbate (vitamin C). Ascorbate enhances the menadione redox cycling, increases the formation of reactive oxygen species and kills K562 cells as shown by more than 65% of LDH leakage after 24 hr of incubation. Since both lactate formation and ATP content are depressed by about 80% following ascorbate/menadione exposure, we suggest that the major intracellular event involved in such a cytotoxicity is related to the impairment of glycolysis. Indeed, NAD(+) is rapidly and severely depleted, a fact most probably related to a strong Poly(ADP-ribose) polymerase (PARP) activation, as shown by the high amount of poly-ADP-ribosylated proteins. The addition of N-acetylcysteine (NAC) restores most of the ATP content and the production of lactate as well. The PARP inhibitor dihydroxyisoquinoline (DiQ) was able to partially restore both parameters as well as cell death induced by ascorbate/menadione. These results suggest that the PARP activation induced by the oxidative stress is a major but not the only intracellular event involved in cell death by ascorbate/menadione. Due to the high energetic dependence of cancer cells on glycolysis, the impairment of such an essential pathway may explain the effectiveness of this combination to kill cancer cells.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Enzyme Activation; Glycolysis; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; NAD; Necrosis; Oxidative Stress; Poly(ADP-ribose) Polymerases; Tumor Cells, Cultured; Vitamin K 3

Carbon tetrachloride (CCl(4): 4 ml/kg body weight as a 1:1 mixture of CCl(4) and mineral oil) was orally administered to rats. After 12 h the activity of plasma AST (aspartate aminotransferase) and ALT (alanine aminotransferase) was significantly higher than that of the control group and plasma AST and ALT activities increased thereafter. These results indicated that the necrotic process was active at about 12 h and developed thereafter. After 2-24 h of CCl(4) administration, the hepatic level of vitamin C, the most sensitive indicator of oxidative stress, decreased significantly, indicating that oxidative stress was significantly enhanced as early as 2 h after CCl(4) intoxication and thereafter. Phosphorylated JNK (c-Jun NH(2)-terminal kinase) and phospho-ERK1/2 (extracellular signal-regulated kinase1/2) were significantly increased transiently 1-3 h after treatment with CCl(4), while phosphorylated p38 decreased significantly 1-24 h after CCl(4) treatment. These results indicated that the change in MAPKs (mitogen activated protein kinases) slightly preceded that in vitamin C, the most sensitive chemical indicator of oxidative stress.

Topics: Animals; Ascorbic Acid; Carbon Tetrachloride Poisoning; Disease Models, Animal; Enzyme Activation; JNK Mitogen-Activated Protein Kinases; Liver; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Necrosis; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Rats; Rats, Wistar; Time Factors

Thioacetamide (400 mg/kg body weight, i.p.) was administered to rats. After 12 h the activity of plasma glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) was significantly higher than that of the control group, and after 24 h plasma GOT and GPT activities strongly increased. These results indicated that the necrotic process was initiated at about 12 h and developed thereafter. By co-administration of dimethyl sulphoxide (DMSO, 18 and 1 h before, and 8 h after administration of thioacetamide: each time, 2.5 ml/kg body weight, p.o.), plasma GOT and GPT were significantly decreased and were even comparable to the control group, showing that DMSO totally prevented the necrotic action of thioacetamide. After 12 and 24 h of thioacetamide administration, the hepatic level of vitamin C, the most sensitive chemical indicator of oxidative stress, decreased significantly, indicating that oxidative stress was significantly enhanced 12 h after thioacetamide intoxication and thereafter. DMSO totally restored the liver vitamin C level, demonstrating that DMSO effectively ameliorated the oxidative stress caused by thioacetamide, resulting in the prevention of necrosis of the liver. Phosphorylated c-Jun NH(2)-terminal kinase (JNK) significantly increased transiently 12 h after treatment with thioacetamide. These results indicated that oxidative stress and the activation of JNK took place almost simultaneously. Phosphorylated extracellular signal-related kinase (ERK) 2 was significantly increased 6-12 h after thioacetamide injection. Phosphorylated p38 MAPK (mitogen activated protein kinase) was significantly decreased 24 h after administration of thioacetamide. DMSO treatment inhibited the change of these MAPKs by thioacetamide, corresponding with the prevention of the liver necrosis as well as the attenuation of oxidative stress.

Topics: Animals; Ascorbic Acid; Aspartate Aminotransferases; Blotting, Western; Dimethyl Sulfoxide; Extracellular Signal-Regulated MAP Kinases; Free Radical Scavengers; JNK Mitogen-Activated Protein Kinases; Liver; Male; Necrosis; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Rats; Rats, Wistar; Thioacetamide; Vitamin E

D-Galactosamine (D-Galn: 300 mg/kg) was intraperitoneally administered to rats. After 6 h the activity of plasma GOT and GPT was significantly higher than that of the control group and plasma GOT and GPT activities increased thereafter. These results indicated that the necrotic process was initiated at about 6 h and developed thereafter. With coadministration of DMSO (1 h before administration of D-Galn: 2.5 mL/kg, oral), plasma GOT and GPT were significantly lower, showing that DMSO inhibited the necrotic action of D-Galn. After 6-24 h of D-Galn administration, the hepatic level of vitamin C, the most sensitive indicator of oxidative stress, decreased significantly, indicating that oxidative stress was significantly enhanced 6 h after D-Galn intoxication and thereafter. DMSO significantly restored the liver vitamin C level 24 h after D-Galn injection, demonstrating that DMSO effectively ameliorated the oxidative stress caused by D-Galn, resulting in the prevention of necrosis of the liver. Phosphorylated JNK and phospho-ERK were significantly increased transiently 6-12 h after treatment with D-Galn. These results indicated that oxidative stress and the activation of JNK took place almost simultaneously. Phosphorylated p38 MAPK was not changed and DMSO treatment did not affect the change of these MAPKs by D-Galn.

Topics: Alanine Transaminase; Analysis of Variance; Animals; Ascorbic Acid; Aspartate Aminotransferases; Blotting, Western; Dimethyl Sulfoxide; Disease Models, Animal; Free Radical Scavengers; Galactosamine; Liver; Male; Mitogen-Activated Protein Kinases; Necrosis; Oxidative Stress; Rats; Rats, Wistar; Time Factors

Arabidopsis chloroplasts have a multi-layered defense against hydrogen peroxide (H(2)O(2)) that includes a stromal and thylakoid ascorbate peroxidase (sAPX and tAPX). Single and double null mutants in SAPX and TAPX (sapx and tapx) were each crossed with ascorbate deficient vtc2. The single, double and triple mutants did not show visual light stress phenotypes when grown at control or high light intensities (CL and HL; 120 and 1,000 micromol photons m(-2) s(-1)). Upon shift from CL to HL, mesophyll of expanded leaves of the triple mutant bleached within hours, with exclusion of the major vein areas; this contrasts to reported patterns of cell death under ozone treatment and calatase deficiency. tapx-vtc2 and sapx-vtc2, but not tapx-sapx or single mutants, showed limited bleaching. Bleaching and necrosis were accompanied by accumulation of H(2)O(2). Cellular concentrations of alpha-tocopherol, ascorbate and glutathione showed dramatic increase in response to HL in all eight genotypes and the four vtc2 genotypes accumulated more glutathione under CL than the others. Transcript analysis of other ROS responsive genes in vtc2 and the triple mutant showed up to 20-fold induction after transition to HL, generally irrespective of genotype. We conclude that chloroplast APX proteins in Arabidopsis can be effectively compensated by other endogenous H(2)O(2) detoxification systems, but that low cellular ascorbate levels in absence of chloroplast APX activity are detrimental to the cell during excess light.

Topics: Arabidopsis; Arabidopsis Proteins; Ascorbate Peroxidases; Ascorbic Acid; Chloroplasts; Gene Expression Regulation, Plant; Hydrogen Peroxide; Light; Mutation; Necrosis; Peroxidases; Plastids; Reactive Oxygen Species; Up-Regulation

Neuronal cell damage following hypoxic-ischemic (HI) brain injury is partly caused by production of free radicals and reactive oxygen species (ROS). Ascorbic acid (AA) is a potent antioxidant, which scavenges various types of ROS. Some studies have shown that it is neuroprotective, however, the issue is still controversial. In this study, we examined the effect of intraventricular AA administration on immature HI brain using the Rice-Vannucci model. After unilateral carotid artery ligation under isoflurane anesthesia, 7-day-old rat pups received varying concentrations of AA (0.04, 0.2, 1 and 5 mg/kg) by intraventricular injection and were exposed to 8% oxygen for 90 min. Vehicle controls received an equal volume of phosphate saline buffer. We assessed the neuroprotective effect of AA at 7 days post-HI. The percent brain damage measured by comparing the wet weight of the ligated side of hemisphere with that of contralateral one was reduced in both 1 and 5 mg/kg groups but not in either 0.04 or 0.2 mg/kg groups compared to vehicle controls (5 mg/kg 16.0 +/- 4.3%, 1 mg/kg 10.9 +/- 5.0%, vs. controls 36.7 +/- 3.6%, P < 0.05). Macroscopic evaluation of brain injury revealed the neuroprotective effect of AA in both 1 and 5 mg/kg groups (5 mg/kg 1.1 +/- 0.4, 1 mg/kg 0.4 +/- 0.3, vs. controls 2.9 +/- 0.3, P < 0.05). Western blots of fodrin on the ligated side also showed that AA significantly suppressed 150/145-kDa bands of fodrin breakdown products, which suggested that AA suppressed activation of calpain. Neuropathological quantitative analysis of cell death revealed that 1 mg/kg of AA injection significantly reduced the number of necrotic cells in cortex, caudate putamen, thalamus and hippocampus CA1, whereas that of apoptotic cells was only reduced in cortex. These findings show that intraventricular AA injection is neuroprotective after HI in immature rats.

Topics: Analysis of Variance; Animals; Animals, Newborn; Antioxidants; Apoptosis; Ascorbic Acid; Blotting, Western; Body Weight; Carrier Proteins; Cell Count; Functional Laterality; Hypoxia-Ischemia, Brain; Hypoxia, Brain; Injections, Intraventricular; Microfilament Proteins; Molecular Weight; Necrosis; Organ Size; Rats; Rats, Wistar

We studied the effect of oral supplementation with L-ascorbic acid (50 mg /100 g body weight (BW) on nickel sulfate (2.0 mg/ 100 g BW, i.p)-induced lipid peroxidation and histopathology in the lung of Wister strain male albino rats. Lipid peroxide and glutathione levels and the activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), were estimated. Nickel sulfate administration significantly increased the level of lipid peroxides and decreased all antioxidant enzyme activities. Nickel sulfate treatment also induced (a) loss of normal characteristics and architectural organization, (b) inflammation in bronchioles, (c) alveolar congestion, (d) alveolar cell hyperplasia, and (e) congestion in the lumen. The simultaneous administration of L-ascorbic acid and nickel sulfate improved both lipid peroxidation and the histopathology of lung when compared with rats receiving nickel sulfate alone. The results indicate that L-ascorbic acid prevents nickel-induced alteration of antioxidant defense mechanisms and histopathology of lung tissue.

Topics: Animals; Antioxidants; Ascorbic Acid; Catalase; Glutathione Peroxidase; Lipid Peroxidation; Lung; Lung Diseases; Male; Necrosis; Nickel; Paraffin Embedding; Rats; Rats, Wistar; Superoxide Dismutase

Altered membrane integrity has been suggested as a major factor in the development of cellular injury during myocardial necrosis. The present study was designed to investigate the effect of the combination of ferulic acid (FA) and ascorbic acid (AA) on lysosomal hydrolases and membrane-bound phosphatases during isoproterenol (ISO) induced myocardial necrosis in rats. Induction of rats with 1SO (150 mg/kg b.wt, i.p.) for 2 days resulted in a significant increase in the activities of lysosomal hydrolases (beta-D-glucuronidase, beta-D-galactosidase, beta-D-N-acetylglucosaminidase, acid phosphatase and cathepsin-D) in the heart and serum. A significant increase in plasma lactate level, cardiac levels of sodium, calcium and a decrease in cardiac level of potassium was also observed, which was paralleled by abnormal activities of membrane-bound phosphatases (Na(+)-K(+) ATPase, Ca(2+) ATPase and Mg(2+) ATPase) in the heart of ISO-administered rats. Pre-co-treatment with the combination of FA (20 mg/kg b.wt) and AA (80 mg/kg b.wt) orally for 6 days significantly attenuated these abnormalities and restored the levels to near normalcy when compared to individual drug treated groups. The combination of FA and AA preserved the membrane integrity by mitigating the oxidative stress and associated cellular damage more effectively when compared to individual treatment groups. In our study, the protection conferred by FA and AA might be through the nitric oxide pathway and by their ability of quenching free radicals. In conclusion, these findings indicate the synergistic modulation of lysosomal hydrolases and membrane phosphatases by the combination of FA and AA.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Ascorbic Acid; Cardiotonic Agents; Cell Membrane; Coumaric Acids; Drug Synergism; Free Radicals; Isoproterenol; Lysosomes; Male; Myocardial Infarction; Myocardium; Necrosis; Nitric Oxide; Oxidative Stress; Phosphoric Monoester Hydrolases; Rats; Rats, Wistar

Avemar (MSC) is a nontoxic fermented wheat germ extract demonstrated to have antitumor effects. Avemar has the potential to significantly improve the survival rate in patients suffering from malignant colon tumors. We studied its effects in the HT-29 human colon carcinoma cell line. Avemar had an inhibiting effect on colonies of HT-29 cells with an IC50 value of 118 microg/ml (7 days of incubation); this value could be decreased to 100 and 75 microg/ml in the presence of vitamin C. In the cell line examined, Avemar induced both necrosis and apoptosis, as demonstrated by Hoechst/propidium iodide staining. The incubation of cells with 3200 microg/ml Avemar for 24 hrs caused necrosis in 28% and the induction of apoptosis in 22% of the cells. Avemar inhibited the cell-cycle progression of HT-29 cells in the G1 phase of the cell cycle. In addition, Avemar inhibited the activity of the key enzyme of de novo DNA synthesis, ribonucleotide reductase. In addition, we determined the effects of Avemar on the activity of cyclooxygenase-1 and -2. Both enzymes were significantly inhibited by Avemar with IC50 values of 100 and 300 microg/ml, respectively. We outline new explanations for its antitumor activity, which might serve as the basis for further studies using Avemar.

Topics: Apoptosis; Ascorbic Acid; Cell Cycle; Cell Line, Tumor; Cyclooxygenase 1; Cyclooxygenase 2; DNA; G1 Phase; Humans; Inhibitory Concentration 50; Membrane Proteins; Necrosis; Plant Extracts; Propidium; Prostaglandin-Endoperoxide Synthases; Ribonucleotide Reductases; Triticum

Reproductive toxicity of chromium is in dispute despite positive findings in rodents. Recently we reported epididymal toxicity of hexavalent chromium (CrVI) in bonnet monkeys and in this paper we report its testicular toxicity.. Adult monkeys (Macaca radiata) were given drinking water containing CrVI (100, 200, 400 p.p.m.) for 6 months and testes were removed for ultrastructural and biochemical analyses.. CrVI treatment disrupted spermatogenesis, leading to accumulation of prematurely released spermatocytes, spermatids and uni- and multinucleate giant cells in the lumen of seminiferous tubules. Transmission electron microscopy revealed granulation of chromatin and vacuolation between acrosomal cap and manchette microtubules of elongated spermatids and in the Golgi area of round spermatids. Pachytene spermatocytes had fragmented chromatin and swollen mitochondria with collapsed cristae. Spermatocytes and spermatogonia in the basal compartment were unaffected. Macrophages containing phagocytosed sperm and dense inclusions in Sertoli cells were seen. Specific activities of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase and concentrations of the non-enzymatic antioxidants glutathione, vitamins A, C and E decreased, while concentrations of H(2)O(2) and hydroxyl radicals increased in the testis of chromium-treated monkeys. Withdrawal of chromium treatment for 6 months normalized spermatogenesis and the status of pro- and antioxidants in the testis.. CrVI disrupts spermatogenesis by inducing free radical toxicity, and supplementation of antioxidant vitamins may be beneficial to the affected subjects.

Topics: Animals; Antioxidants; Ascorbic Acid; Catalase; Chromatin; Chromium; Cytoplasm; Free Radicals; Glucosephosphate Dehydrogenase; Glutathione; Glutathione Peroxidase; Glutathione Reductase; Golgi Apparatus; Hydrogen Peroxide; Hydroxyl Radical; Macaca radiata; Macrophages; Male; Microscopy, Electron, Transmission; Necrosis; Oxidative Stress; Phagocytosis; Reactive Oxygen Species; Sertoli Cells; Spermatids; Spermatocytes; Superoxide Dismutase; Testis; Time Factors; Vacuoles; Vitamin A; Vitamin E

Since activated macrophages generate potentially deleterious reactive oxygen species, we studied whether ascorbic acid might function as an antioxidant in these cells. Thioglycollate-elicited murine peritoneal macrophages contained about 3 mM ascorbate that was halved by culture in ascorbate-free medium. However, the cells took up added ascorbate to concentrations of 6-8 mM by a high-affinity sodium-dependent transport mechanism. This likely reflected the activity of the SVCT2 ascorbate transporter, since its message and protein were present in the cells. Activation of the cells by phagocytosis of latex particles depleted intracellular ascorbate, although not below the basal levels present in the cells in culture. Glutathione (GSH) was unaffected by phagocytosis, suggesting that ascorbate was more sensitive to the oxidant stress of phagocytosis than GSH. Phagocytosis induced a modest increase in reactive oxygen species as well as a progressive loss of alpha-tocopherol, both of which were prevented in cells loaded with ascorbate. These results suggest that activated macrophages can use ascorbate to lessen self-generated oxidant stress and spare alpha-tocopherol, which may protect these long-lived cells from necrosis or apoptosis.

Topics: alpha-Tocopherol; Animals; Antioxidants; Apoptosis; Ascorbic Acid; Astrocytes; Cell Membrane; Cells, Cultured; Dehydroascorbic Acid; Fluoresceins; Glutathione; Macrophages, Peritoneal; Mice; Necrosis; Oxidative Stress; Reactive Oxygen Species; Thioglycolates; Time Factors

In this study we investigated the effect of insulin on neuronal viability and antioxidant defense mechanisms upon ascorbate/Fe2+-induced oxidative stress, using cultured cortical neurons. Insulin (0.1 and 10 microM) prevented the decrease in neuronal viability mediated by oxidative stress, decreasing both necrotic and apoptotic cell death. Moreover, insulin inhibited ascorbate/Fe2+-mediated lipid and protein oxidation, thus decreasing neuronal oxidative stress. Increased 4-hydroxynonenal (4-HNE) adducts on GLUT3 glucose transporters upon exposure to ascorbate/Fe2+ were also prevented by insulin, suggesting that this peptide can interfere with glucose metabolism. We further analyzed the influence of insulin on antioxidant defense mechanisms in the cortical neurons. Oxidative stress-induced decreases in intracellular uric acid and GSH/GSSG levels were largely prevented upon treatment with insulin. Inhibition of phosphatidylinositol-3-kinase (PI-3K) or mitogen-induced extracellular kinase (MEK) reversed the effect of insulin on uric acid and GSH/GSSG, suggesting the activation of insulin-mediated signaling pathways. Moreover, insulin stimulated glutathione reductase (GRed) and inhibited glutathione peroxidase (GPx) activities under oxidative stress conditions, further supporting that insulin neuroprotection was related to the modulation of the glutathione redox cycle. Thus, insulin may be useful in preventing oxidative stress-mediated injury that occurs in several neurodegenerative disorders.

Topics: Aldehydes; Animals; Apoptosis; Ascorbic Acid; Cell Survival; Cells, Cultured; Cerebral Cortex; Female; Ferrous Compounds; Glucose Transporter Type 3; Glutathione; Insulin; Lipid Peroxidation; Necrosis; Neurons; Oxidative Stress; Rats; Rats, Wistar; Stimulation, Chemical; Uric Acid

We have demonstrated cell membrane destruction activity by carboxylic acid derivatives (CADs) mainly tri-sodium citrate, in neoplastic cell lines and, to a far lesser extent, in normal human peripheral blood mononuclear cells (hPBMC). Flow cytometric (FACS) analysis was applied to Annexin-V and Propidium Iodide (PI) stained cells to evaluate the degree of the apoptosis induced by citrate in the following cell lines: CCRF-CEM (shortened to CEM), H9, and Jurkat (T-Cells), Raji and WIL2-NS (B-Cells), HL-60 (myeloblasts), K562 (myelocytes) and U937 (monocytes). We also tested normal hPBMC. Before staining with Annexin/PI, manual cell counts were performed on 24- and 48-h-old cell cultures. Cell supernatants were assayed for lactate dehydrogenase (LDH). LDH values in samples correlated with enhanced apoptosis by FACS analysis. For comparison, ascorbate and 2 other CADs including, acetate and lactate were also evaluated for the induction of apoptosis. In addition, the ability of tri-sodium citrate to induce apoptosis in the presence and the absence of several antineoplastic drugs, such as dexamethasone, arsenic trioxide, hydrocortisone, 6-mercaptopurine, and methotrexate were tested on Jurkat cells. FACS, LDH, and cell count values all demonstrated an enhanced degree of apoptotic cell death in Jurkat cells by citrate. In most of our investigated cells, except for the H9 cell line, citrate has induced a greater degree of apoptosis than acetate which induced a greater degree than lactate (see Fig. 1.0). The nature of the cell death by ascorbate appeared to be due to necrosis rather than apoptosis. Pilot studies on normal hPBMC showed that citrate alone or in combination with antineoplastic drugs caused minimal cell death. Thus citrate might be of benefit in some chemotherapy treatments in order to reduce drug toxicity or possibly enhance drug activities in certain neoplasias.

Topics: Acetic Acid; Antineoplastic Agents; Apoptosis; Ascorbic Acid; Citrates; Dose-Response Relationship, Drug; Drug Combinations; Flow Cytometry; Humans; L-Lactate Dehydrogenase; Lactic Acid; Leukocytes, Mononuclear; Lymphocytes; Necrosis; Pilot Projects; Sodium Citrate; Tumor Cells, Cultured

Proliferation control in adult retinal pigment epithelial (ARPE) cells is an essential factor in the clinical management of proliferative vitreoretinopathy (PVR). Factors which inhibit PVR and which are without toxic potential are therefore of interest in controlling proliferation. The aim of the present study was to gain insight into a possible function of high intraocular ascorbic acid levels as a physiological modulator of proliferation.. Adult retinal pigment epithelial cells were incubated in vitro with increasing concentrations of ascorbic acid (0.5-4 mmol, pH 7.4). Cell proliferation was assayed by the bromide-deoxy-uridine (BrdU) assay. The culture medium (CM) containing ascorbic acid was replaced with normal CM and the recovery of proliferation was measured after 24 hours. In order to be able to distinguish between proliferation inhibition, apoptosis, necrosis and recovery of proliferation, we performed TUNEL assays and fluorescence analysis cell-counter (FAC) analysis.. Ascorbic acid significantly inhibits ARPE cell proliferation if it is present in concentrations above 2 mmol. Proliferation resumed in all ARPE cell cultures after pre-incubation with ascorbic acid, indicating that direct toxicity of ascorbic acid is a negligible factor. The time-point and extent of recovery in proliferation was dependent on the initial ascorbic acid concentration. Fluorescence-labelled cell counts on apoptosis markers (FAC) data showed some induction of apoptosis and necrosis after incubation with 4 mmol ascorbic acid.. Ascorbic acid has a dose-dependent influence on the proliferation of vital ARPE cells. This possibly reflects the role of ascorbic acid at a physiological level within the vitreous cavity in preventing proliferative vitreoretinopathy (PVR). These findings may stimulate the development of new strategies in the clinical treatment of PVR.

Topics: Apoptosis; Ascorbic Acid; Cell Division; Cell Line; Cell Separation; Dose-Response Relationship, Drug; Flow Cytometry; Free Radical Scavengers; Humans; Necrosis; Pigment Epithelium of Eye

Binge drinking of alcohol causes cardiac dysfunction in some people. The mechanism remains unclear. This study was designed to investigate high doses of alcohol-induced oxidative stress and apoptosis in cardiomyocytes and protective effects of antioxidants. Cardiomyocytes isolated from 1- to 2-day-old Sprague-Dawley rats were treated with ethanol at doses of 0 mM, 50 mM, 100 mM, and 200 mM for 24 hours. Vitamin E (1 mM) and vitamin C (0.2 mM) were added to medium 1 hour before addition of ethanol. Results showed typical apoptosis: chromatin condensation, membrane blebbing, shrinkage, and cytoplasm condensation. Apoptosis is concentration-dependent in the range of 0 to 100 mM ethanol (apoptosis rates were respectively 0.68%, 2.03%, and 9.66% at ethanol concentration of 0 mM, 50 mM, and 100 mM). Necrotic cells became greatly increased in the 200 mM ethanol-treated group. Intracellular production of reactive oxygen intermediates increased as mitochondrial membrane potential decreased after ethanol treatment. Cytochrome c was found to be greater in the cytosol of the ethanol-treated groups. Activity of caspase-3 was higher in ethanol-treated groups (P < 0.05). Both vitamin E and vitamin C inhibited oxidative stress and myocyte apoptosis in ethanol-treated groups (P < 0.05). In conclusion, our data indicated that acute high-dose ethanol treatment primarily induces cardiomyocyte apoptosis at concentration up to 100 mM while necrosis is predominate at 200 mM. The underlying mechanism appears to involve mitochondrial damage via an increase in oxidative stress and releasing cytochrome c, which activates caspases that initiate chromatin fragmentation and apoptosis. Antioxidants, to a large extent, inhibit oxidative stress and apoptosis induced by ethanol.

Topics: Animals; Antioxidants; Apoptosis; Ascorbic Acid; Caspase 3; Caspases; Cells, Cultured; Central Nervous System Depressants; Cytochromes c; Ethanol; Flow Cytometry; Fluorescent Antibody Technique; Free Radicals; Membrane Potentials; Microscopy, Fluorescence; Myocytes, Cardiac; Necrosis; Oxidation-Reduction; Oxidative Stress; Rats; Reactive Oxygen Species; Vitamin E

Protease inhibitor treatment strongly diminishes mortality in HIV-infected patients. This treatment has also been associated with lipodystrophy and has been shown to alter adipocyte differentiation. The protease inhibitor nelfinavir has been indirectly implicated in the appearance and development of lipodystrophic syndrome, as well as in adipocyte cell death. The aim of this study was to evaluate the effects of nelfinavir on the 3T3-F442A adipocyte cell line. Nelfinavir (30 microM) induced cell death of 3T3-F442A adipocytes by a necrotic process that was not mediated by TNF-alpha. Treatment of cells with this protease inhibitor led to a significant increase in expression of the heme oxygenase-1 gene that could be reduced by 100 microM of the antioxidant ascorbate. Moreover, ascorbate had a protective effect on nelfinavir-induced necrosis, decreasing the percentage of necrotic cells by 70%. Our results show that nelfinavir induces necrosis of adipocytes mediated by a cellular increase of reactive oxygen species. This deleterious effect could be counterbalanced by ascorbate.

Topics: 3T3 Cells; Adipocytes; Animals; Apoptosis; Ascorbic Acid; Cell Line; Heme Oxygenase-1; HIV Protease Inhibitors; Mice; Necrosis; Nelfinavir; Oxidative Stress

Eighteen and twenty-four hours after intraperitoneal administration of D-galactosamine (1g/kg body weight) to rats, the activity of caspase-3-like protease in the liver increased significantly compared with that in the control group given saline. Histological examinations including the in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method found apoptotic hepatocytes 18 hr after the administration of D-galactosamine. Caspase-3 activity was barely detectable in the plasma of control rats, but increased significantly 24 hr after drug administration along with a dramatic increase in glutamate-oxaloacetate transaminase (GOT). These results indicated that D-galactosamine causes apoptosis in the liver by activating caspase-3, which is released to the plasma by secondary necrosis. The concentration of lipid hydroperoxides in the liver increased significantly 24 hr after D-galactosamine administration. In contrast, the concentration of vitamin C in the liver decreased significantly 18 and 24 hr after D-galactosamine administration. These results suggest that D-galactosamine induces severe oxidative stress in the liver, leading to extensive necrosis.

Topics: Animals; Apoptosis; Ascorbic Acid; Galactosamine; Lipid Peroxides; Liver; Male; Necrosis; Oxidative Stress; Rats; Rats, Wistar; Vitamin E

Maize (Zea mays L. cv kanaujia) plants grown with Zn [10 (control), 0.1 (low) and 20 microM (high)], were investigated for concentration of antioxidants and activities of antioxidative enzymes in leaves. Young leaves of low Zn plants developed whitish-necrotic spots. Leaves of both low and high Zn plants showed decrease in chlorophyll concentration and accumulation of lipid peroxides, ascorbate and dehydroascorbate, associated with a decrease in the activity of ascorbate peroxidase and superoxide dismutase. Low and high Zn, however, showed diverse effect on glutathione reductase. While low Zn increased the activity of glutathione reductase, high Zn decreased its activity. Zinc effect on antioxidative constituents suggested Zn involvement in sustaining the antioxidative defense system in maize leaves.

Topics: Antioxidants; Ascorbate Peroxidases; Ascorbic Acid; Chlorophyll; Dehydroascorbic Acid; Glutathione Reductase; Lipid Peroxides; Necrosis; Peroxidases; Plant Leaves; Superoxide Dismutase; Zea mays; Zinc

In the present study, we explored whether mitogenic stimulation of dexamethasone (DXM)- and cyclosporine A (CsA)-immunosuppressed peripheral blood lymphocytes (PBML) induced apoptosis or necrosis and their relation with the production of reactive oxygen intermediates. Our results indicate that both phenomena can occur in these cells and that antioxidants such as N-acetyl cysteine (NAC) and ascorbic acid (AA) can modulate them. However, DXM-induced apoptosis was only partially inhibited by NAC and AA, suggesting that DXM-treated PBMC had an additional apoptotic pathway independent of ROIs. Furthermore, we observed that the inhibition of apoptosis by antioxidants correlated with an increased cell proliferation, suggesting that the immunomodulation of both DXM and CsA may be related to induction of apoptosis. The ability to differentially modulate apoptosis and necrosis by antioxidants opens new possibilities in the management of immunosuppressive therapy, since the inhibition of necrosis may avoid inflammation and the tissue damage associated with immunosuppressors.

Topics: Acetylcysteine; Adult; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Antioxidants; Apoptosis; Ascorbic Acid; Cyclosporine; Dexamethasone; Glucocorticoids; Humans; Immunosuppressive Agents; In Situ Nick-End Labeling; L-Lactate Dehydrogenase; Lectins, C-Type; Lymphocyte Activation; Lymphocytes; Male; Necrosis; Phytohemagglutinins; Superoxides

Local skin necrosis after extravasation of doxorubicin hydrochloride (Adriamycin), a widely used chemotherapeutic agent, is a common problem in cancer patients. Even though several treatment options have been proposed for extravasation injury, there is still controversy regarding the management of such lesions. The aim of this study was to compare the efficacy of saline infiltration, vitamin C infiltration, suction technique, and early surgical excision as a treatment in a rat extravasation model. The authors planned their study in two stages. In stage 1, the lowest effective dose of doxorubicin at which a homogeneous skin necrosis was formed and the method of administration were investigated. Intradermal and subpannicular injections were made for six rats, using six different concentrations of doxorubicin (0.33, 0.5, 0.66, 1.0, 1.33, and 1.5 mg/ml). In stage 1, the intradermal injection produced homogeneous and uniform tissue necrosis. In stage 2, the efficacy of saline infiltration (group 1), vitamin C infiltration (group 2), suction (group 3), suction and saline washout (group 4), suction and vitamin C washout (group 5), and early surgical excision (group 6) was compared. The treatment options were applied 2 hours after doxorubicin injection. At the end of the seventh day, the presence and size of ulcers at the injection site were calculated. Fourteen days after injection, a histopathologic examination was performed for each treatment and control group. In groups 1 and 3, there was no statistically significant difference in the size of necrosis compared with the control groups. In groups 2, 4, and 5, the size of necrosis was smaller compared with the control groups, and this was statistically significant. Furthermore, in group 4 (suction and saline washout) and group 5 (suction and vitamin C washout), the calculated area of necrosis was smaller compared with other treatment groups, and this was statistically significant. The findings supported the assertion that suction and saline or vitamin C washout reduce necrotic tissue size in extravasation injury.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Doxorubicin; Extravasation of Diagnostic and Therapeutic Materials; Injections, Intradermal; Injections, Subcutaneous; Necrosis; Rats; Rats, Wistar; Skin; Skin Ulcer; Sodium Chloride; Suction

After 12, 18, and 24 h of oral administration of carbon tetrachloride (as a 1:1 mixture with mineral oil: 4 ml/kg body weight) to rats, the activity of caspase-3-like protease in the liver increased significantly compared to that in the control group that was given mineral oil (4 ml/kg). In plasma, the activity of caspase-3 was barely detectable in the control rat, but increased significantly 24 h after drug administration along with a dramatic increase in glutamate oxaloacetate transaminase. These results indicate that carbon tetrachloride causes apoptosis in the liver by activating caspase-3, which is released to plasma by secondary necrosis. After 18 and 24 h of carbon tetrachloride administration, the liver concentration of hydrophilic vitamin C was decreased significantly, while that of hydrophobic vitamin E was not affected. The plasma concentration of vitamins C and E was not influenced significantly. These results suggest that carbon tetrachloride induces oxidative stress mainly in the aqueous phase of the liver cell.

Topics: Animals; Apoptosis; Ascorbic Acid; Carbon Tetrachloride; Caspase 3; Caspases; Chemical and Drug Induced Liver Injury, Chronic; Enzyme Activation; Liver; Male; Necrosis; Oxidative Stress; Rats; Rats, Sprague-Dawley; Time Factors; Vitamin E

Vitamin C (ascorbate) is toxic to tumour cells, and has been suggested as an adjuvant cancer treatment. Our goal was to determine if ascorbate, in combination with other antioxidants, could kill cells in the SW620 hollow fibre in vitro solid tumour model at clinically achievable concentrations. Ascorbate anti-cancer efficacy, alone or in combination with lipoic acid, vitamin K3, phenyl ascorbate, or doxorubicin, was assessed using annexin V staining and standard survival assays. 2-day treatments with 10 mM ascorbate increased the percentage of apoptotic cells in SW620 hollow fibre tumours. Lipoic acid synergistically enhanced ascorbate cytotoxicity, reducing the 2-day LC(50)in hollow fibre tumours from 34 mM to 4 mM. Lipoic acid, unlike ascorbate, was equally effective against proliferating and non-proliferating cells. Ascorbate levels in human blood plasma were measured during and after intravenous ascorbate infusions. Infusions of 60 g produced peak plasma concentrations exceeding 20 mM with an area under the curve (24 h) of 76 mM h. Thus, tumoricidal concentrations may be achievable in vivo. Ascorbate efficacy was enhanced in an additive fashion by phenyl ascorbate or vitamin K3. The effect of ascorbate on doxorubicin efficacy was concentration dependent; low doses were protective while high doses increased cell killing.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Carcinoma; Colonic Neoplasms; Dose-Response Relationship, Drug; Doxorubicin; Drug Interactions; Humans; Necrosis; Thioctic Acid; Tumor Cells, Cultured

24-Hydroxycholesterol, the main cholesterol elimination product of the brain is increased in serum of Alzheimer patients. This oxysterol behaves neurotoxic towards the human neuroblastoma cell line, SH-SY5Y. Here we demonstrate, that 24-hydroxycholesterol-induced neurotoxicity in differentiated SH-SY5Y cells was due to apoptosis, as indicated by DNA-fragmentation, caspase-3 activation and a decrease of the mitochondrial membrane potential. Free radicals were generated, resulting in the death of 75% of the cells within 48h; neurotoxicity in differentiated SH-SY5Y cells was partially prevented by physiological concentrations of vitamin E (50-100 microM) in that 75% of the cells survived. Physiological concentrations of estradiol-17beta (1-100nM) elicited a protective effect in differentiated cells, which was not significant; however, in undifferentiated cells a significant protection was noted by this steroid hormone. Vitamin C and melatonin did not prevent 24-hydroxycholesterol-induced neurotoxicity. These in vitro data support the in vivo observed beneficial effects reported as circumstantial evidence of vitamin E and estradiol-17beta treatment in the prevention and therapy of neurodegenerative disease.

Topics: Antioxidants; Ascorbic Acid; Brain; Caspase 3; Caspases; Estradiol; Free Radicals; Humans; Hydroxycholesterols; Melatonin; Membrane Potentials; Mitochondria; Necrosis; Neuroblastoma; Neurons; Oxidative Stress; Tumor Cells, Cultured; Vitamin E

We have investigated the ability of intracellular vitamin C to protect human umbilical vein endothelial cells from exposure to hypochlorous acid (HOCl) and a range of derived chloramines. Ascorbate provided minimal protection against the cytotoxicity induced by these oxidants, as measured by propidium iodide uptake. In contrast, there was a marked effect on apoptosis, monitored by caspase-3 activation and phosphatidylserine exposure. Extended incubation of the cells with glycine chloramine or histamine chloramine completely blocked apoptosis initiated in the cells by serum withdrawal. This effect was significantly abrogated by ascorbate. Inhibition of apoptosis required the oxidant to be present for an extended period after serum withdrawal and occurred prior to caspase-3 activation. General protection of thiols by ascorbate was not responsible for the protection of apoptosis, because intracellular oxidation by HOCl or chloramines was not prevented in supplemented cells. The results suggest a new role for vitamin C in the regulation of apoptosis. We propose that, by protection of an oxidant-sensitive step in the initiation phase, ascorbate allows apoptosis to proceed in endothelial cells under sustained oxidative stress.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Caspase 3; Caspases; Cell Survival; Cells, Cultured; Chlorine; Dose-Response Relationship, Drug; Endothelium, Vascular; Enzyme Activation; Humans; Hypochlorous Acid; Models, Biological; Necrosis; Oxidants; Oxidative Stress; Oxygen; Time Factors; Umbilical Veins

The potential of ascorbic acid and two botanical decoctions, green tea and cat's claw, to limit cell death in response to oxidants were evaluated in vitro.. Cultured human gastric epithelial cells (AGS) or murine small intestinal epithelial cells (IEC-18) were exposed to oxidants - DPPH (3 microM), H2O2 (50 microM), peroxynitrite (300 microM) - followed by incubation for 24 hours, with antioxidants (10 microg/ml) administered as a 1 hour pretreatment. Cell number (MTT assay) and death via apoptosis or necrosis (ELISA, LDH release) was determined. The direct interactions between antioxidants and DPPH (100 microM) or H2O2 (50 microM) were evaluated by spectroscopy.. The decoctions did not interact with H2O2, but quenched DPPH although less effectively than vitamin C. In contrast, vitamin C was significantly less effective in protecting human gastric epithelial cells (AGS) from apoptosis induced by DPPH, peroxynitrite and H2O2 (P < 0.001). Green tea and cat's claw were equally protective against peroxynitrite and H2O2, but green tea was more effective than cat's claw in reducing DPPH-induced apoptosis (P < 0.01). Necrotic cell death was marginally evident at these low concentrations of peroxynitrite and H2O2, and was attenuated both by cat's claw and green tea (P < 0.01). In IEC-18 cells, all antioxidants were equally effective as anti-apoptotic agents.. These results indicate that dietary antioxidants can limit epithelial cell death in response to oxidant stress. In the case of green tea and cat's claw, the cytoprotective response exceed their inherent ability to interact with the injurious oxidant, suggestive of actions on intracellular pathways regulating cell death.

Topics: Animals; Antioxidants; Apoptosis; Ascorbic Acid; Cat's Claw; Cells, Cultured; Humans; Hydrogen Peroxide; Intestinal Mucosa; Mice; Necrosis; Oxidants; Peroxynitrous Acid; Tea

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

Previously it was reported that hyperoxia induced death of the human lung adenocarcinoma cell line (A549 cells) by necrosis, not by apoptosis. This study examined proliferation and death of untransformed human small airway epithelial (SAE) cells in normoxia or hyperoxia in comparison with A549 cells. We tested the hypothesis that SAE cells respond differently to hyperoxic injury than do A549 cells. We measured total cell number and viability, thymidine incorporation (SAE cells only), lactate dehydrogenase (LDH) release, and apoptotic changes as markers for cell proliferation and death. Protective effects of antioxidant vitamins also were examined in SAE cells. In normoxia, subconfluent SAE cells had less apoptosis and fewer detached cells, but higher thymidine incorporation than did near-confluent cells. Hyperoxia suppressed thymidine incorporation and augmented apoptosis in both subconfluent and near-confluent SAE cells. Hyperoxia decreased the total cell number only in subconfluence, whereas SAE cell viability declined with hyperoxia in near confluence, but not in subconfluence. For SAE cells, necrosis assessed by LDH release was minimal in all conditions and was not augmented by hyperoxia in SAE cells. In contrast, normoxic A549 cells proliferated more rapidly than did SAE cells with a large number of cells detached during the culture. A549 cells underwent necrotic cell death under confluent or in hyperoxic conditions, but had much less apoptotic cell death. In SAE cells, vitamin E partially prevented the decline of thymidine incorporation with hyperoxia in subconfluence and protected against apoptotic changes with hyperoxia in both subconfluent and near-confluent conditions. Vitamin C prevented apoptosis with hyperoxia only in near-confluent SAE cells. Thus, SAE cells maintained balanced apoptosis and cell proliferation that were altered by cell density and hyperoxia and demonstrated very little necrosis with hyperoxia. Although A549 cells underwent cell death mainly by necrosis, they also were influenced by cell density and hyperoxia. Cell density also determined specific antioxidant vitamin protection in SAE cells.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Cell Count; Cell Line; Cell Survival; Epithelial Cells; Humans; Hyperoxia; Immunohistochemistry; L-Lactate Dehydrogenase; Lung; Necrosis; Thymidine; Vitamin E

The free radicals nitric oxide and superoxide react to form peroxynitrite (ONOO-), a potent cytotoxic oxidant. This study was designed to evaluate whether addition of L-Ascorbic acid (AsC) into the culture medium decreases peroxynitrite-induced apoptosis in human intestinal epithelial (T84) and murine macrophage (RAW 264.7) cell lines. In Experiment 1, T84 and RAW 264.7 cells were divided in two protocols: (1) treated with 100-300 microM ONOO- and incubated for 4 h, and (2) treated with 10-100 microM ONOO- and incubated overnight (14 h). In Experiment 2, T84 and RAW 264.7 cells were treated with 300 microM ONOO- and 500 microM AsC and incubated for 4 h. In Experiment 3, T84 and RAW 264.7 cells were preincubated for 2 h with 500 microM AsC then exposed to 300 microM ONOO- for 4 h. Cell viability (necrosis) was assessed by trypan blue dye exclusion. Apoptosis was quantified with a cell death detection ELISA assay. In the 4 h protocol, ONOO- induced apoptosis in T84 and RAW 264.7 cells, at levels of 100-300 microM. Concentrations of ONOO- greater than 300 microM caused necrosis. In contrast, extension of the protocol to 14 h indicated that ONOO- induced apoptosis at lower concentrations (50;-75 microM), with concentrations > 75 microM resulting in necrosis. AsC administered to the media or with preincubation plus washout, decreased peroxynitrite-induced apoptosis in T84 and RAW 264.7 cells. These results indicate that ONOO- may contribute to the pathophysiology of gut inflammation by promoting cell death and ascorbic acid may protect against peroxynitrie-induced damage.

Topics: Animals; Apoptosis; Ascorbic Acid; Cell Line; Cell Survival; Culture Media; Epithelium; Free Radical Scavengers; Humans; Intestines; Macrophages; Mice; Necrosis; Nitrates; Trypan Blue

Possible biochemical events involved in L-2-chloropropionic acid (L-CPA)-induced delayed cerebellar granule cell necrosis following N-methyl-D-aspartate activation were studied in vivo. We examined whether the calcium-sensitive proteolytic enzymes, the calpains, may be activated by L-CPA or whether the generation of excess quantities of cytotoxic free radicals may play a role in the neurotoxicity produced by oral administration of L-CPA (750 mg/kg, pH 7.0). Evidence for free radical-induced cellular damage was examined using biochemical approaches such as examining brains from L-CPA-treated rats for increased lipid peroxidation, DNA damage, or protein oxidation. Second, the ability of antioxidants to provide neuroprotective activity against L-CPA-induced neurotoxicity was examined in vivo. Western blotting using antibodies against spectrin (alpha-fodrin) demonstrated evidence for calpain (EC 3.4.22.17) activation in the cerebellum, but not in the cerebral cortex of L-CPA-treated rats at 36 and 48 hr after L-CPA dosing. In contrast, there was no evidence for oxidative damage to cerebellar proteins or lipids in L-CPA-treated rat brains compared to controls. We also could not find evidence for DNA damage using the TUNEL method for the detection of single- and/ or double-strand breakage in situ in L-CPA-treated brains. We examined whether a number of reported antioxidants may be effective against L-CPA-induced neurotoxicity. The aminosteroids U74389G and U83836E, the free radical scavengers 3-methyl-1-phenylpyrazolin-5-one and N-tert-butylphenylnitrone, and the iron chelator N-ethoxy-2-ethyl-3-hydroxypyridin-4-one were all ineffective in attenuating L-CPA neurotoxicity. We suggest that L-CPA-induced cerebellar necrosis is the result of calpain activation which results in the degradation of cytoskeletal proteins and other proteins necessary for cellular biochemistry. We could find no evidence of oxidative damage to cerebellar proteins, lipids, or DNA as a result of excess amounts of free radicals, and selective antioxidants were unable to provide neuroprotection against L-CPA neurotoxicity, suggesting that oxidative stress does not play a role in the granule cell necrosis.

Topics: Administration, Oral; Animals; Antioxidants; Ascorbic Acid; Aspartic Acid; Blotting, Western; Calpain; Cerebellum; Free Radicals; Glutamic Acid; Hydrocarbons, Chlorinated; Lipid Peroxidation; Male; Necrosis; Nervous System Diseases; Neurons; Oxidative Stress; Propionates; Rats; Spectrin

The objective of this study was to determine the impact of limited ascorbate (Asc) availability on type II cell sensitivity to oxidant stress. Guinea pigs were fed diets with or without Asc for 18 days, and type II cells were isolated. Although lung Asc was decreased by 90% in deficient animals (scorbutic), type II cell Asc was decreased by 50%. Upon treatment with 250 microM H2O2, the necrotic injury was twofold greater in scorbutic cells compared with control cells. With 100 microM H2O2 treatment, apoptotic injury was twofold greater in scorbutic cells compared with control cells. Although there was less necrotic injury in cells exposed to 95% O2, the scorbutic cells were more sensitive than control cells. Asc pretreatment protected against necrosis and apoptosis. The Asc analog isoascorbate provided partial protection and suggested that part of the protection was not chemical detoxification but was Asc specific. We conclude that limited Asc availability resulted in a functional type II cell but a cell more sensitive to oxidant-induced injury.

Topics: Animals; Apoptosis; Ascorbic Acid; Ascorbic Acid Deficiency; Epithelial Cells; Guinea Pigs; Hydrogen Peroxide; Kinetics; Lung; Necrosis; Oxidative Stress; Pulmonary Alveoli; Time Factors

The aim of the present study was to investigate the oxidative status in astrocytoma. Samples of brain tissue from the centre to the periphery of the tumor were obtained from 11 astrocytoma patients undergoing computer tomography-guided stereotaxic operation, who had been previously treated with the corticosteroid dexamethasone. Part of the sample was investigated histologically for clarification of tumor type, and the presence of neoplastic and non-neoplastic tissue and necrosis. The rest was used for the quantification of the antioxidants ascorbic acid, uric acid, glutathione and cysteine by high performance liquid chromatography, and for quantification of DNA. Levels of antioxidants were calculated as micrograms/g fresh tissue and mumol/g DNA, a parameter related to cell content. There was significantly more DNA in neoplastic samples than in non-neoplastic ones, indicating increased cell density. Uric acid (micrograms/g fresh tissue) was significantly increased in neoplastic compared with non-neoplastic tissue, and levels were even higher in necrotic tissue. There were no significant differences between neoplastic and non-neoplastic tissue levels of ascorbic acid, glutathione or cysteine, expressed as micrograms/g fresh tissue. However, when levels of these three compounds were expressed as mumol/g DNA, i.e. taking into account the higher cell density, ascorbic acid, glutathione and cysteine were significantly reduced in neoplastic samples compared with non-neoplastic ones. Results thus show that there are differences between the antioxidant levels in astrocytoma and non-neoplastic tissue, providing additional support for the hypothesis that free radicals play a role in tumor growth.

Topics: Adult; Aged; Antioxidants; Artifacts; Ascorbic Acid; Astrocytoma; Biopsy; Brain Chemistry; Brain Edema; Brain Neoplasms; Combined Modality Therapy; Cysteine; Dexamethasone; DNA, Neoplasm; Female; Free Radicals; Glioblastoma; Glutathione; Humans; Male; Middle Aged; Necrosis; Neoplasm Proteins; Oxidation-Reduction; Oxidative Stress; Phenytoin; Solubility; Stereotaxic Techniques; Tomography, X-Ray Computed; Uric Acid; Water

1. Nephrotoxicity was induced in rats by injecting gentamicin intramuscularly (i.m.) at a dose of 80 mg/kg for 6 days. Treated animals demonstrated a typical pattern of nephrotoxicity characterized by increased serum creatinine and urea concentrations, and by necrosis of proximal tubular epithelium. 2. Pretreatment of rats with iron (Fe3+) at daily i.m. doses of 2, 4 and 8 mg/kg for 14 days, with gentamicin given during the last 6 days of treatment, significantly potentiated the gentamicin-induced increases in creatinine and urea concentrations and exacerbated renal histological damage. 3. Gentamicin significantly increased serum Fe3+ concentration in rats treated with Fe3+ and gentamicin, compared to Fe(3+)-treated rats. 4. The Fe3+ antidote deferoxamine (100 mg/kg, i.m.) given with gentamicin was ineffective in antagonizing the potentiating effect of Fe3+ on gentamicin-induced nephrotoxicity. 5. Ascorbic acid (50 mg/kg, i.m. for 14 days) was ineffective in altering the nephrotoxicity of gentamicin (80 mg/kg) given during the last 6 days of treatment. At a dose of 100 mg/kg for 14 days, ascorbic acid significantly reduced gentamicin-induced increases in creatinine and urea levels, and ameliorated proximal tubular damage. However, at a dose of 200 mg/kg, ascorbic acid exacerbated gentamicin-induced increases in creatinine and urea levels and increased the severity of the histological damage.

Topics: Animals; Ascorbic Acid; Blood Urea Nitrogen; Creatinine; Deferoxamine; Dose-Response Relationship, Drug; Drug Synergism; Female; Gentamicins; Iron; Kidney Tubules, Proximal; Necrosis; Rats; Rats, Sprague-Dawley

Extravasation of doxorubicin hydrochloride during i.v. infusions can cause serious local complications due to the action of free radicals which are produced as a result of this leakage. An experiment was carried out using female Wistar rats to study the protective effect of alpha-tocopherol against the tissular necrosis produced by 0.05 mg of doxorubicin hydrochloride. alpha-Tocopherol was administered by two vehicles, one emulsified and the other gelled, with butylated hydroxytoluene and ascorbic acid used as antioxidants, respectively. No differences were observed in the diameters of the ulcers with each treatment in the various groups of animals relative to the control group. Conversely, differences were found (p < 0.05) in the period of chronic lesion between the animals treated with alpha-tocopherol and those used as a control group, irrespective of the vehicle used. These results lead to the conclusion that accidental toxicity resulting from the leakage of doxorubicin hydrochloride in the skin can be mitigated by applying alpha-tocopherol topically, due to its regenerating action in the damaged cutaneous zones. This effect is independent of the vehicle used and also of the antioxidant employed in the elaboration of the formulas.

Topics: Animals; Ascorbic Acid; Butylated Hydroxytoluene; Doxorubicin; Female; Injections, Intradermal; Necrosis; Oxidation-Reduction; Rats; Rats, Wistar; Skin Ulcer; Vitamin E

The deuterated benzaldehyde derivative zilascorb(2H), 5,6-O-benzylidene-d-L-ascorbic acid, was administered once daily by i.v. injection in nude mice with grafted tumours of a human malignant melanoma (E.E.) and ovarian carcinoma (OVCAR-3) origins. Like benzaldehyde, zilascorb(2H) has been shown to induce protein synthesis inhibition at otherwise non-toxic doses in cells grown in vitro, and acts reversibly in the sense that protein synthesis returns to normal shortly after removal of the drug. The present data indicate that daily injections with zilascorb(2H) induce a tumour volume growth inhibitory effect in both tumour xenografts studied. Furthermore, from histological examinations of each single tumour it was found that tumours of drug-treated animals, although smaller than those of placebo-treated (i.e. control) animals, had, on average, a higher necrotic fraction than control tumours. Thus, it is concluded that zilascorb(2H) induces tumour necrotisation and not just inhibition of the rate of tumour cell production. Continued measurement of tumour volume after ended treatment with zilascorb(2H) indicated that surviving tumour cells resumed their normal growth rate immediately. The reversibility of the effect induced by this compound, earlier observed in vitro only, is therefore here confirmed to be valid also in two different tumour xenografts in vivo. The present data accords well with the assumption that protein synthesis inhibition is the primary cellular effect of zilascorb(2H) in vivo. We therefore conclude that zilascorb(2H)-induced cancer cell lethality in tumour xenografts probably comes as a secondary consequence of prolonged protein synthesis inhibition.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Benzylidene Compounds; Cell Division; Deuterium; Dose-Response Relationship, Drug; Female; Humans; Male; Melanoma; Mice; Mice, Inbred BALB C; Mice, Nude; Middle Aged; Necrosis; Neoplasm Proteins; Neoplasm Transplantation; Ovarian Neoplasms; Transplantation, Heterologous

To investigate molecular responses to lipid peroxidative stimuli in neoplastic cells, lipid peroxidation was induced in liver of rats bearing 3'-methyl-4-dimethylaminoazobenzene-induced hepatocellular carcinoma by injecting a high dose of carbon tetrachloride (CCl4), a strong lipoperoxidative reagent. Normal rat livers with or without CCl4 treatment served as controls. CCl4 administration markedly provoked fatty metamorphosis, visualized by oil red O staining, in normal livers while minimal fatty changes were seen in hepatocellular carcinomas, where necrosis was often observed instead. After CCl4 treatment, the thiobarbituric acid values (representing levels of lipid peroxides in the tissue) were increased two-fold in the untreated normal liver, but were unchanged in the cancer tissue. Levels of vitamin C, an acutely reactive antioxidant, measured by high-performance liquid chromatography were not influenced by the CCl4 injection in the cancer tissue whereas a significant decrease was evident in normal livers. The total fatty acid content, measured by gas chromatography, was significantly lower in the cancer tissue than in the normal liver while the ratio of polyunsaturated fatty acids (PUFAs) in total fatty acids was little changed. Resistance of hepatocellular cancer cells to fatty metamorphosis and their susceptibility to necrosis induced by free radicals may be due to the paucity of the target PUFAs in their cell membrane fraction, resulting in low levels of lipid peroxides. Peroxidation of PUFAs might act as a "shock absorber" against free radical-induced toxic cell death in normal cells.

Topics: Animals; Ascorbic Acid; Azo Compounds; Carbon Tetrachloride; Fatty Acids; Fatty Liver; Lipid Peroxidation; Liver; Liver Neoplasms, Experimental; Male; Methyldimethylaminoazobenzene; Necrosis; Rats; Thiobarbiturates

The mechanisms of the liver damage produced by three glutathione (GSH) depleting agents, bromobenzene, allyl alcohol and diethylmaleate, was investigated. The change in the antioxidant systems represented by alpha-tocopherol (vitamin E) and ascorbic acid were studied under conditions of severe GSH depletion. With each toxin liver necrosis was accompanied by lipid peroxidation that developed only after severe depletion of GSH. The hepatic level of vitamin E was decreased whenever extensive lipid peroxidation developed. In the case of bromobenzene intoxication, vitamin E decreased before the onset of lipid peroxidation. Changes in levels of the ascorbic and dehydroascorbic acid indicated a redox cycling of vitamin C with the oxidative stress induced by all the three agents. Such a change of the redox state of vitamin C (increase of the oxidized over the reduced form) may be an index of oxidative stress preceding lipid peroxidation in the case of bromobenzene. In the other cases, such a change is likely to be a consequence of lipid peroxidation. Experiments carried out with vitamin E deficient or supplemented diets indicated that the pathological phenomena occurring as a consequence of GSH depletion depend on hepatic levels of vitamin E. In vitamin E deficient animals, lipid peroxidation and liver necrosis appeared earlier than in animals fed the control diet. Animals fed a vitamin E supplemented diet had an hepatic vitamin E level double that obtained with a commercial pellet diet. In such animals, bromobenzene and allyl alcohol had only limited toxicity and diethylmaleate none in spite of comparable hepatic GSH depletion. Thus, vitamin E may largely modulate the expression of the toxicity by GSH depleting agents.

Topics: 1-Propanol; Animals; Antioxidants; Ascorbic Acid; Bromobenzenes; Chromatography, High Pressure Liquid; Glutathione; Lipid Peroxidation; Liver; Male; Maleates; Malondialdehyde; Mice; Necrosis; Propanols; Time Factors; Vitamin E

Both Trolox (a water-soluble analogue of alpha-tocopherol) and ascorbic acid were more effective than superoxide dismutase or catalase in protecting myocyte cell cultures from free radical attack (induced by hypoxanthine and xanthine oxidase). In a canine model of two hours of left anterior descending coronary artery occlusion followed by four hours of reperfusion, Trolox and ascorbic acid reduced the area of infarction within the area at risk. The Trolox group received 500 mL of deoxygenated saline solution containing 2.0 g of Trolox, 3.0 g of ascorbic acid, and 18 mg of EDTA (ethylenediaminetetraacetic acid) infused into the ascending aorta 30 seconds before and four minutes after reperfusion. Saline controls received 500 mL of deoxygenated saline solution containing 18 mg of EDTA. The angioplasty group had unmodified reperfusion by simple release of the occlusion. The area at risk and the area infarcted were estimated with Evans blue and triphenyl tetrazolium hydrochloride stains, respectively. The ratio of the area infarcted to the area at risk was significantly lower with Trolox (angioplasty, 30.4% +/- 5.1%; saline, 20.8% +/- 2.9%; and Trolox, 8.7% +/- 4.0%; p less than 0.01). In summary, the antioxidants Trolox and ascorbic acid effectively reduced myocardial necrosis after ischemia.

Topics: Animals; Antioxidants; Ascorbic Acid; Benzopyrans; Cells, Cultured; Chromans; Disease Models, Animal; Dogs; Free Radicals; Heart; Hemodynamics; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Necrosis

Although diquat produces massive oxidant stress in both Fischer and Sprague-Dawley rats, the Fischer rats sustain hepatic necrosis and the Sprague-Dawley rats do not. A previous example of probable hepatic necrosis produced by an oxidant stress-generating compound was demonstrated in animals in which glutathione peroxidase activity had been decreased by a dietary deficiency of selenium. In the present study the susceptible Fischer rats had hepatic peroxidase activities equal to the resistant Sprague-Dawley rats. Hepatotoxic doses of diquat did not diminish hepatic glutathione peroxidase or reductase activities or hepatic content of ascorbic acid, NADPH or protein sulfhydryls. Hepatic nonprotein sulfhydryls were decreased by 50% but recovered to control values by 6 h. Biliary excretion of oxidized glutathione in the Fischer rat after administration of diquat was 4 times that observed after administration in Sprague-Dawley rats. The diquat-induced peroxidation of hepatic lipids was indicated by small increases in the 11-, 12-, and 15-hydroxyeicosatetraenoic acids, as quantitated by a new gas chromatography-mass spectrometry assay. Thus, acute lethal injury caused by redox cycling compounds that generate reactive oxygen species does not exhibit a number of the biochemical alterations in vivo that occur with cell death produced by similar compounds in isolated hepatocyte systems.

Topics: Alanine Transaminase; Animals; Ascorbic Acid; Aspartate Aminotransferases; Diquat; Glutathione; Glutathione Disulfide; Glutathione Peroxidase; Glutathione Reductase; Hydroxy Acids; Liver; Male; NADP; Necrosis; Pyridinium Compounds; Rats; Rats, Inbred F344; Rats, Inbred Strains; Stress, Physiological

The intravenous or intraperitoneal injection of amidopyrine and sodium nitrite to rats induces liver necrosis caused by endogenic synthesis of carcinogenic N-nitrosodimethylamine (NDMA). Ascorbic acid, which inhibits this synthesis when injected intravenously, phenobarbital, which is an inductor of enzymatic decomposition when injected intraperitoneally, prevented the formation of necrosis.

Topics: Aminopyrine; Animals; Ascorbic Acid; Dimethylnitrosamine; Injections, Intraperitoneal; Injections, Intravenous; Liver; Male; Necrosis; Nitrites; Phenobarbital; Rats

Rats fed a vitamin E-deficient diet containing 10% "stripped" corn oil had reduced growth rate and elevated platelet count by 12 weeks of age, and a normocytic anemia with elevated reticulocytes by 16 weeks of age. After 5 months, rats became emaciated and developed kyphoscoliosis. Some rats developed skin ulcers and tremors, and mortality was high. Neuromuscular lesions included a chronic necrotizing myopathy and localized axonal dystrophy. There was also a selective activation of lysosomes in the central nervous system microcirculation. Liver ascorbic acid of deficient rats was the same as in those receiving vitamin E. Urinary excretion of p-hydroxyphenylpyruvate after a tyrosine load was also the same in deficient and control rats. It was concluded that neither vitamin C synthesis or utilization was affected the E-deficient rats.

Topics: Age Factors; Anemia; Animals; Ascorbic Acid; Female; Kyphosis; Male; Muscular Diseases; Necrosis; Nervous System Diseases; Rats; Scoliosis; Skin Ulcer; Thrombocytosis; Vitamin E Deficiency

Topics: Alanine Transaminase; Aminopyrine; Animals; Ascorbic Acid; Chemical and Drug Induced Liver Injury; Dimethylnitrosamine; Liver; Liver Diseases; Necrosis; Nitrites; Nitrosamines; Rats

Although the effect of cold and heat stress on myocardial metabolisms has been widely studied, this parameter has not been investigated over a wide range of environmental temperatures after myocardial infarction. Since high as well as low temperatures are known to adversely affect the myocardium, changes in enviromental temperature are likely to be of great importance to patients suffering from acute coronary insult. Therefore, the myocardial metabolism was studied at different environmental temperatures in albino rats with isoproterenol-induced infarct-like myocardial necrosis. Male albino rats weighing 100 to 150 g were selected for the study. The investigations included ECG (lead II), histology, serum free fatty acids (FFA), serum triglycerides (TGS), cardiac noradrenaline, cardiac glycogen, and adrenal ascorbic acid, after the induction of myocardial necrosis. The biochemical changes were minimum between 10 and 15 degrees C while, at 4 degrees C, marked changes were observed. No significant change was seen in the serum triglycerides.

Topics: Adrenal Glands; Alanine Transaminase; Animals; Ascorbic Acid; Aspartate Aminotransferases; Cardiomyopathies; Fatty Acids, Nonesterified; Glycogen; Heart; Isoproterenol; Male; Myocardial Infarction; Myocardium; Necrosis; Norepinephrine; Organ Size; Rats; Temperature

Topics: Adolescent; Adult; Alkaline Phosphatase; Ascorbic Acid; Aspartate Aminotransferases; Bilirubin; Carotenoids; Cholesterol; Drainage; Female; Folic Acid; Glucose Tolerance Test; Hepatitis; Humans; Ileum; Intestinal Absorption; Intestinal Obstruction; Intestine, Small; Jejunum; Lipids; Male; Middle Aged; Necrosis; Obesity; Postoperative Complications; Surgical Wound Infection; Thrombophlebitis; Triglycerides; Uric Acid; Vitamin A; Vitamin B 12; Vitamin E; Xylose

Topics: Ascorbic Acid; Aspirin; Atrophy; Auscultation; Cellulitis; Drug Combinations; Edema; Humans; Leg Ulcer; Lymphatic System; Macrophages; Necrosis; Occlusive Dressings; Pigmentation Disorders; Posture; Respiration; Rest; Thrombophlebitis; Time Factors; Valsalva Maneuver; Varicose Veins; Venous Insufficiency; Venous Pressure

Topics: Ampicillin; Animals; Anti-Bacterial Agents; Antibiotics, Antineoplastic; Ascorbic Acid; Chick Embryo; Culture Techniques; Erythromycin; Erythromycin Ethylsuccinate; Fibroblasts; Guinea Pigs; Irritants; Kanamycin; Methicillin; Mice; Necrosis; Neomycin; Novobiocin; Oleandomycin; Oxacillin; Penicillin G; Potassium

Topics: Animals; Ascorbic Acid; Chick Embryo; Culture Techniques; Cytoplasm; Depression, Chemical; Dihydrostreptomycin Sulfate; Drug Synergism; Fibroblasts; Guinea Pigs; Mice; Necrosis; Pantothenic Acid; Staphylococcus; Stimulation, Chemical; Sulfates

Topics: Animals; Ascorbic Acid; Biotin; Carbon Tetrachloride Poisoning; Centrifugation; Chemical and Drug Induced Liver Injury; Folic Acid; Liver; Necrosis; Nicotinic Acids; Pantothenic Acid; Proteins; Pyridoxine; Rats; Riboflavin; Specimen Handling; Thiamine; Vitamin A; Vitamin B 12; Vitamin E; Vitamins

Topics: Alkaline Phosphatase; Animals; Ascorbic Acid; Calcium; Chelating Agents; Glutamates; Glycine; Kidney; Male; Mercury Poisoning; Necrosis; Potassium; Pyridoxine; Rats; Regeneration; Sodium

Topics: Animals; Ascorbic Acid; Guinea Pigs; Liver; Liver Glycogen; Male; Methods; Necrosis; Rats; Thiamine; Time Factors; Vibration

Topics: Aging; Animals; Ascorbic Acid; Carbon Tetrachloride Poisoning; Chemical and Drug Induced Liver Injury; Chlorobutanol; Gossypium; Granulation Tissue; Liver Diseases; Metabolism; Necrosis; Rats; Starvation

Topics: Adrenocorticotropic Hormone; Ascorbic Acid; Blood Coagulation Disorders; Diagnosis; Drug Therapy; Fibrinolysis; Humans; Ischemia; Necrosis; Pathology; Prednisone; Promethazine; Purpura; Purpura Fulminans; Tetracycline

Topics: Adrenocorticotropic Hormone; Ascorbic Acid; Blood Coagulation Disorders; Diagnosis; Drug Therapy; Fibrinolysis; Humans; Ischemia; Necrosis; Pathology; Prednisone; Promethazine; Purpura; Purpura Fulminans; Tetracycline

Topics: Ascorbic Acid; Fluorescence; In Vitro Techniques; Necrosis; Plants; Tobacco Mosaic Virus

Topics: Ascorbic Acid; Borrelia Infections; Dental Prophylaxis; Diet; Diet Therapy; Drug Therapy; Folic Acid; Fusobacterium; Gingivitis; Gingivitis, Necrotizing Ulcerative; Humans; Hydrogen Peroxide; Necrosis; Pathology; Penicillins; Staphylococcal Infections; Streptococcal Infections; Sulfadiazine; Sulfamerazine; Sulfamethazine; Vitamin B Complex

Topics: Animals; Ascorbic Acid; Dietetics; Glutathione; Liver; Necrosis; Rats; Vitamins