leukotriene-c4 and Disease-Models--Animal

The human ATP-binding cassette transporter multidrug resistance protein 1 (MRP1), encoded by ABCC1, was initially identified because of its ability to confer multidrug resistance in lung cancer cells. It is now established that MRP1 plays a role in protecting certain tissues from xenobiotic insults and that it mediates the cellular efflux of the proinflammatory cysteinyl leukotriene C4 as well as a vast array of other endo- and xenobiotic organic anions. Many of these are glutathione (GSH) or glucuronide conjugates, the products of Phase II drug metabolism. MRP1 also plays a role in the cellular efflux of the reduced and oxidized forms of GSH and thus contributes to the many physiological and pathophysiological processes influenced by these small peptides, including oxidative stress. In this review, the pharmacological and physiological aspects of MRP1 are considered in the context of the current status and future prospects of pharmacological and genetic modulation of MRP1 activity.

Topics: Animals; Clinical Trials as Topic; Disease Models, Animal; Drug Resistance, Neoplasm; Glutathione; Humans; Leukotriene C4; Molecular Targeted Therapy; Multidrug Resistance-Associated Proteins; Substrate Specificity

Leukotrienes are potent inflammatory mediators synthesized locally within the cardiovascular system through the 5-lipoxygenase pathway of arachidonic acid metabolism. The leukotrienes, consisting of dihydroxy leukotriene LTB4 and the cysteinyl leukotrienes LTC4, LTD4 and LTE4, act by targeting cell surface receptors expressed on inflammatory cells and on structural cells of vessel walls. LTB, induces leukocyte activation and chemotaxis via high- and low-affinity receptor subtypes (BLT1 and BLT2), respectively. Recently, BLT, receptors were found on human vascular smooth muscle cells, inducing their migration and proliferation. Cysteinyl leukotrienes are vasoconstrictors and induce endothelium-dependent vascular responses through the CysLT, and CysLT2 receptor subtypes. There is also pharmacological evidence for the existence of further CysLT receptor subtypes. Taken together, experimental and genetic studies suggest a major role of leukotrienes in atherosclerosis and in its ischemic complications such as acute coronary syndromes and stroke. Furthermore, the effects on vascular smooth muscle cells suggest a role in the vascular remodeling observed after coronary angioplasty, as well as in aortic aneurysm. Further experimental and clinical studies are needed to determine the potential of therapeutic strategies targeting the leukotriene pathway in cardiovascular disease.

Topics: Angioplasty, Balloon, Coronary; Animals; Aortic Aneurysm; Arachidonic Acid; Atherosclerosis; Cardiovascular Diseases; Cell Movement; Coronary Restenosis; Disease Models, Animal; Guinea Pigs; Humans; Hypertension; Leukotriene Antagonists; Leukotriene B4; Leukotriene C4; Leukotriene D4; Leukotriene E4; Leukotrienes; Mice; Muscle, Smooth, Vascular; Rats; Receptors, Leukotriene; Stroke

Cysteinyl leukotrienes (CysLTs: LTC4, LTD4, and LTE4) are a family of potent inflammatory mediators that appear to contribute to the pathophysiologic features of allergic rhinitis. Because treatment with a CysLT1 receptor antagonist and a 5-lipoxygenase inhibitor modified allergen-induced nasal blockage in patients with allergic rhinitis, and CysLTs were detected in nasal cavity lavage fluid, it has been suggested that CysLTs act as significant inflammatory mediators in allergic rhinitis. The role of CysLTs was evaluated in our experimental allergic rhinitis model in sensitized guinea pigs which shows biphasic nasal blockage, sneezing and nasal hyperresponsiveness to LTD4 induced by repetitive inhalation challenge with Japanese cedar pollen. In this model, the CysLT1 receptor antagonist pranlukast suppressed the late-phase nasal blockage but not early blockage and sneezing. Nasal hyperresponsiveness (nasal blockage) to LTD4 was largely blocked by pranlukast, naphazoline, and N omega-nitro-L-arginine-methyl ester. The results demonstrate that nasal blockage induced by CysLTs is mainly due to dilatation of nasal blood vessels, which can be induced by the nitric oxide produced through CysLT1 receptor activation. On the other hand, when pollen inhalation challenge was performed in the presence of nasal hyperresponsiveness, antigen-induced biphasic nasal blockage and sneezing were considerably enhanced and CysLTs contributed to both symptoms, suggesting that nasal hyperresponsiveness induces aggravation of antigen-induced nasal symptoms. The results presented in this study further suggest that our model is a good representative of human allergic rhinitis and offer evidence that CysLTs are chemical mediators mainly responsible for allergic nasal symptoms.

Topics: Allergens; Animals; Bronchial Provocation Tests; Chromones; Cryptomeria; Disease Models, Animal; Guinea Pigs; Humans; Inflammation Mediators; Leukotriene Antagonists; Leukotriene C4; Leukotriene D4; Leukotriene E4; Lipoxygenase Inhibitors; Membrane Proteins; Pollen; Receptors, Leukotriene; Rhinitis, Allergic, Seasonal

Topics: Animals; Anti-Allergic Agents; Asthma; Cytokines; Disease Models, Animal; Immunoglobulin E; Inflammation; Leukotriene B4; Leukotriene C4; Lung; Mice; Mice, Inbred BALB C; Mucoproteins; Respiratory Hypersensitivity

Allergic rhinitis (AR) is an allergic disease induced by the T helper 2 (TH2) lymphocyte immune response, where its mediators are the primary cause of clinical symptoms. Environmental factors are the primary determinants of the allergic response in genetically susceptible individuals. This study investigates the effects of climate conditions (warm, cold, humid, and dry) on allergic rhinitis. AR models were created in mice under 4 different conditions. We investigated AR-related behavior (sneezing and nose rubbing), as well as total immunoglobulin E (IgE), histamine, interleukin-4 (IL-4), leukotriene (LT) B4 and LTC4 levels, and gene expression of CysLT1R, HRH1, and MUC5a. Nose rubbing, histamine levels, and the expression of MUC5a and HRH1 were increased in AR models in cold conditions, and sneezing was increased in AR models kept in dry conditions. LTB4 and LTC4 levels and the expression of CysLT1R in AR models kept in a wet environment also significantly increased compared with the control group. The levels of total IgE and IL-4 showed no significant changes. Air temperature and humidity affect AR pathophysiology, and weather conditions can be essential in controlling AR.

Topics: Animals; Disease Models, Animal; Histamine; Humidity; Immunoglobulin E; Interleukin-4; Leukotriene C4; Mice; Mice, Inbred BALB C; Nasal Mucosa; Ovalbumin; Rhinitis, Allergic; Sneezing; Temperature

Allergic rhinitis (AR) is a common type of inflammatory disease with symptoms including rhinorrhea, fatigue, sneezing, and disturbed sleep. AR affects nearly 40% of peoples worldwide with the increased numbers of new cases. In this work, the study was conducted to disclose the anti-inflammatory and antiallergic properties of cirsilineol against the ovalbumin (OVA)-sensitized AR in mice. AR was provoked in BALB/c mice through the OVA challenge 30 days along with 10 and 20 mg/kg of cirsilineol treatment. The nasal symptoms, i.e., rubbing and sneezing was monitored after the final OVA challenge. The status of OVA-specific IgE, PGD2, and LTC4 was investigated using assay kits. The status of pro-inflammatory markers also examined using assay kits. The levels of oxidative markers, SOD activity, and pro-inflammatory markers in the spleen mononuclear cells (SMEs) were studied by using respective assay kits. The mRNA expression of TXNIP was assessed using RT-PCR study. The 10 and 20 mg/kg of cirsilineol treatment effectively decreased the sneezing and nasal rubbings in OVA-provoked mice. Cirsilineol also decreased the IgE, PGD2, and LTC4 status in the AR animals. The status of pro-inflammatory markers, i.e., IL-4, IL-5, IL-6, IL-33 and TNF-α was found to be decreased in the cirsilineol administered AR mice. Cirsilineol effectively reduced the ROS and MDA and improved SOD in the OVA-challenged SMCs. The mRNA expression of TXNIP was appreciably suppressed by the cirsilineol treatment. Altogether, these findings proved the beneficial actions of cirsilineol against the OVA-triggered AR in mice. The additional studies on the cirsilineol could lead to the development of new drug for AR management.

Topics: Animals; Anti-Allergic Agents; Biomarkers; Carrier Proteins; Cells, Cultured; Disease Models, Animal; Eosinophils; Flavones; Histamine; Immunoglobulin E; Leukotriene C4; Mice, Inbred BALB C; Nasal Lavage Fluid; Ovalbumin; Oxidative Stress; Prostaglandin D2; Rhinitis, Allergic; Spleen; Thioredoxins

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

The occurrence of chronic obstructive pulmonary disease (COPD) will lead to physiological and pathological variations and endogenous metabolic disorders. A traditional Chinese medicine formula, HuaTanJiangQi decoction (HTJQ), exhibits an unambiguous therapeutic effect on COPD in China. Nevertheless, the mechanism of its therapeutic effect on COPD is not clear. With this purpose, pulmonary function, histopathological and the inflammatory factors in bronchoalveolar lavage fluid (BALF) in rats model of COPD were investigated. Then, ultra high-performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) analysis and multivariate statistical analysis were used to further reveal the mechanism of HTJQ therapeutic effect on COPD via metabolomics study. The results showed that the characteristics of lung tissues were significantly reversed, the concentration of LTB4 and LTC4 were gradually decreased, and the lung function began to recover after HTJQ treatment. These typical indicators of COPD in HTJQ intervention group were reversed similar to the control group, suggested that HTJQ has a therapeutic effect on COPD. Moreover, 32 dysregulated metabolites, including Thromboxane a2, Sphingosine 1-phosphate, PC(18:2(9Z,12Z)/18:1(11Z)), Leukotriene B4, Glutathione, Arachidonic acid, Sphingosylphosphocholine acid, N-Acetyl-leukotriene e4, Lysopc(18:1(11Z)), L-Cysteine, and Guanosine diphosphate. All the altered metabolites were associated with the onset and development of COPD, and involved in glycerophospholipid metabolism, sphingolipid metabolism, glutathione metabolism, and arachidonic acid metabolism, which were significantly changed in rats model with COPD. Generally, these findings provide a systematic view of metabolic changes linked to the onset and development of COPD, also indicated that HTJQ could provide satisfactory therapeutic effects on COPD and metabolomics study can be utilized to further understand the molecular mechanisms.

Topics: Administration, Oral; Animals; Biomarkers; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Dosage Forms; Leukotriene B4; Leukotriene C4; Lung; Metabolome; Pulmonary Disease, Chronic Obstructive; Rats, Sprague-Dawley; Respiratory Function Tests

The cysteinyl leukotrienes (CysLTs), i.e. LTC

Topics: Acetates; Animals; Anti-Inflammatory Agents, Non-Steroidal; Bile Acids and Salts; Colitis; Cyclopropanes; Disease Models, Animal; Gene Expression; Genes, Reporter; HEK293 Cells; Hep G2 Cells; Humans; Leukotriene Antagonists; Leukotriene C4; Leukotriene D4; Leukotriene E4; Luciferases; Mice; Mice, Knockout; Molecular Docking Simulation; Quinolines; RAW 264.7 Cells; Receptors, G-Protein-Coupled; Receptors, Leukotriene; Recombinant Fusion Proteins; Sulfides

Conventional allergic rhinitis (AR) treatments have limitations due to the lack of safety and complete cure strategy. We evaluated the effects of silent information regulator 1 (SIRT1), a multifunctional molecule involved in a variety of inflammatory pathways, on murine AR model. Ovalbumin (OVA)-induced murine model was constructed, and recombinant SIRT1 was administered into the nostril continuously. The expression of SIRT1 was measured at mRNA and protein levels, and the allergic symptoms were evaluated. Protein levels of OVA-specific IgE, leukotriene C4 (LTC4), eosinophil cation protein (ECP), prostaglandin D2 (PGD2), as well as different inflammatory cytokine mediators in the serum and nasal lavage fluid (NLF), were assessed by ELISA. The effects of SIRT1 on human primary nasal epithelial cells challenged with tumour necrosis factor (TNF)-α were also evaluated by investigating the HMGB1/TLR4 signalling pathway. Administration of SIRT1 significantly alleviated OVA-induced AR symptoms with lower numbers of sneezing and nasal rubbing events, decreased levels of OVA-specific IgE, LTC4, ECP, PGD2, less inflammatory cells and downregulated levels of Th2 type cytokines. SIRT1 also reduced the genes of HMGB1/TLR4 signalling pathway in the murine model and cultured human nasal epithelial cells. Expression of SIRT1 is impaired in OVA-induced AR model. The administration of SIRT1 alleviates the allergic symptoms of mice, regulates the production of pro-inflammatory mediators predominantly produced by Th2 cells in AR and attenuates expressions of proteins relevant to HMGB1/TLR4 signalling pathway. All the results showed that SIRT1 is promising as a therapeutic agent of AR.

Topics: Animals; Cells, Cultured; Disease Models, Animal; Down-Regulation; Eosinophil Cationic Protein; Female; HMGB1 Protein; Humans; Immunoglobulin E; Leukotriene C4; Mice; Mice, Inbred BALB C; Nasal Lavage Fluid; Nasal Mucosa; Ovalbumin; Prostaglandin D2; Recombinant Proteins; Rhinitis, Allergic; Signal Transduction; Sirtuin 1; Th2 Cells; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha

Topics: Animals; Anti-Allergic Agents; Anti-Asthmatic Agents; Anti-Inflammatory Agents; Asthma; Bone Marrow Cells; Cell Degranulation; Dermatitis, Atopic; Disease Models, Animal; Female; Immunoglobulin E; Lactones; Leukotriene C4; Mast Cells; Mice; Mice, Inbred BALB C; Ovalbumin; Phosphorylation; Respiratory Hypersensitivity; Sesquiterpenes; Signal Transduction

IgE/Ag-stimulated mast cells release various pro-allergic inflammatory mediators, including histamine, eicosanoids, and pro-inflammatory cytokines. NecroX-5, a cell permeable necrosis inhibitor, showed cytoprotective effects in both in vitro and in vivo models. However, the anti-allergic effect of NecroX-5 has not yet been investigated. The aims of this study were to evaluate the anti-allergic activity of NecroX-5 in vivo and to investigate the underlying mechanism in vitro.. The anti-allergic activity of NecroX-5 was evaluated in vitro using bone marrow-derived mast cells (BMMCs) and IgE receptor-bearing RBL-2H3 or KU812 cells and in vivo using a mouse model of passive anaphylaxis. The levels of histamine, eicosanoids (PGD2 and LTC4 ), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured using enzyme immunoassay kits. The mechanism underlying the action of NecroX-5 was investigated using immunoblotting, immunoprecipitation, and gene knockdown techniques.. NecroX-5 markedly inhibited mast cell degranulation and the synthesis of eicosanoids, TNF-α, and IL-6 by suppressing the activation of Syk, LAT, phospholipase Cγ1, MAP kinases, the Akt/NF-κB pathway, and intracellular Ca(2+) mobilization via the activation of phosphatase SHP-1. Oral administration of NecroX-5 effectively suppressed mast cell-dependent passive cutaneous and systemic anaphylactic reactions in a dose-dependent manner.. NecroX-5 might be a potential candidate for the development of a novel anti-allergic agent that suppresses IgE-dependent mast cells signaling.

Topics: Anaphylaxis; Animals; Antigens; Arachidonate 5-Lipoxygenase; Calcium; Cell Degranulation; Cell Line; Cyclooxygenase 2; Cytokines; Disease Models, Animal; Heterocyclic Compounds, 4 or More Rings; Immunoglobulin E; Intracellular Signaling Peptides and Proteins; Leukotriene C4; Male; Mast Cells; Mice; Prostaglandin D2; Protein Binding; Protein Tyrosine Phosphatase, Non-Receptor Type 6; Protein-Tyrosine Kinases; Signal Transduction; Sulfones; Syk Kinase

Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen that causes hemorrhagic colitis. Under some circumstances, Shiga toxin (Stx) produced within the intestinal tract enters the bloodstream, leading to systemic complications that may cause the potentially fatal hemolytic-uremic syndrome (HUS). Despite STEC human infection is characterized by acute inflammation of the colonic mucosa, little is known regarding the role of proinflammatory mediators like cysteine leukotrienes (cysLTs) in this pathology. Thus, the aim of this work was to analyze whether leukotriene C4 (LTC4) influences STEC pathogenesis in mice. We report that exogenous LTC4 pretreatment severely affected the outcome of STEC gastrointestinal infection. LTC4-pretreated (LTC4+) and STEC-infected (STEC+) mice showed an increased intestinal damage by histological studies, and a decreased survival compared to LTC4-non-pretreated (LTC4-) and STEC+ mice. LTC4+/STEC+ mice that died after the infection displayed neutrophilia and high urea levels, indicating that the cause of death was related to Stx2-toxicity. Despite the differences observed in the survival between LTC4+ and LTC4- mice after STEC infection, both groups showed the same survival after Stx2-intravenous inoculation. In addition, LTC4 pretreatment increased the permeability of mucosal intestinal barrier, as assessed by FITC-dextran absorption experiments. Altogether these results suggest that LTC4 detrimental effect on STEC infection is related to the increased passage of pathogenic factors to the bloodstream. Finally, we showed that STEC infection per se increases the endogenous LTC4 levels in the gut, suggesting that this inflammatory mediator plays a role in the pathogenicity of STEC infection in mice, mainly by disrupting the mucosal epithelial barrier.

Topics: Animals; Disease Models, Animal; Disease Susceptibility; Escherichia coli Infections; Hemolytic-Uremic Syndrome; Intestines; Leukotriene C4; Mice, Inbred BALB C; Shiga-Toxigenic Escherichia coli; Survival Analysis

Five new terpenes (1-5) and ten known compounds (6-15) were isolated from Inula japonica, and their structures were identified by spectroscopic analysis. Compounds 3 and 14 showed positive inhibitory effects on nitric oxide production. Furthermore, compound 14 suppressed both leukotriene C4 synthesis and degranulation in c-kit ligand-induced bone marrow-derived mast cells.

Topics: Animals; Anti-Inflammatory Agents; Cell Degranulation; Cell Line; Disease Models, Animal; Flowers; Inhibitory Concentration 50; Inula; Leukotriene C4; Lipopolysaccharides; Macrophages; Male; Mast Cells; Medicine, East Asian Traditional; Mice; Mice, Inbred BALB C; Molecular Structure; Nitric Oxide; Plant Extracts; Plants, Medicinal; Terpenes

Synthesis of cysteinyl leukotrienes (cys-LT) is thought to cause inflammatory disorders such as bronchial asthma and allergic rhinitis. Recent reports have suggested that leukotriene C4 (LTC4 ) is an important regulator of pulmonary fibrosis. This study examined the effect of LTC4 in LTC4 synthase-overexpressed transgenic mice with bleomycin-induced pulmonary fibrosis. The function of lung-derived fibroblasts from transgenic mice was also investigated.. Bleomycin was administrated to transgenic mice and wild-type (WT) mice by intratracheal instillation. Concentrations of interleukin (IL)-4 and -13, interferon-γ, and transforming growth factor (TGF)-β1 in bronchoalveolar lavage fluid were measured 1, 3, 7 and 14 days after the administration of bleomycin. Lung tissue was examined histopathologically on day 14. In addition, lung-derived fibroblasts from transgenic and WT mice were cultured for 7 days. Expression of TGF-β1 mRNA was measured by real-time polymerase chain reaction.. Both the pathological scores for pulmonary fibrosis (3.8 ± 0.4 vs 2.0 ± 0.1, P < 0.05) and the levels of IL-4 (12.1 ± 2.3 vs <7.8 pg/mL, P < 0.05), IL-13 (26.5 ± 5.2 vs <7.8 pg/mL, P < 0.01) and TGF-β1 (211.1 ± 30.2 vs 21.3 ± 1.2 pg/mL, P < 0.01) on day 14 were significantly greater in transgenic than in WT mice. Furthermore, the reduction of LTC4 by pranlukast hydrate, a cys-LT1 receptor antagonist, in fibroblasts from transgenic significantly (P < 0.05) decreased the expression of TGF-β1 mRNA (by ∼50%) compared with those from WT mice.. Overexpression of LTC4 , amplifies bleomycin-induced pulmonary fibrosis in mice. Our findings suggest a role for LTC4 in lung fibrosis.

Topics: Animals; Bleomycin; Cells, Cultured; Disease Models, Animal; Glutathione Transferase; Interferon-gamma; Interleukin-13; Interleukin-4; Leukotriene C4; Lung; Mice; Mice, Inbred BALB C; Mice, Transgenic; Pulmonary Fibrosis

KOB03 is a polyherbal medicine derived from an oriental prescription traditionally used to treat allergic diseases. In the present study, we compared the efficacy of KOB03 with modern drugs such as ketotifen and montelukast in an experimental mouse model of allergic rhinitis (AR). Ketotifen is a H1 receptor antagonist and montelukast is a leukotriene receptor antagonist. Mice were treated with KOB03, ketotifen or montelukast in an established AR mouse model using ovalbumin (OVA)-sensitized/challenged BALB/c mice. The treatment of KOB03 had inhibitory effects on symptom scores, serum levels of OVA-specific IgE, histamine, leukotriene C4, IL-4, TNF-α, and IL-1β in AR mice, and the histolopathological changes of nasal mucosa with mucin release and inflammation. AR mice treated with KOB03 had significantly lower serum levels of OVA-specific IgE, LTC4, IL-4, and IL-1β than mice treated with ketotifen, whereas they only had significantly lower serum levels of OVA-specific IgE and IL-4 than those treated with montelukast. In addition, the histolopathological changes of nasal mucosa with eosinophil infiltration were significantly lower in the KOB03-treated mice than those in the ketotifen and montelukast-treated group. These results suggest that KOB03 has therapeutic potential for treating AR like other modern medicines.

Topics: Acetates; Animals; Anti-Allergic Agents; Antigens; Cyclopropanes; Cytokines; Disease Models, Animal; Histamine H1 Antagonists; Immunoglobulin E; Ketotifen; Leukotriene Antagonists; Leukotriene C4; Male; Mice; Mice, Inbred BALB C; Nasal Mucosa; Ovalbumin; Plant Extracts; Quinolines; Rhinitis, Allergic; Rhinitis, Allergic, Perennial; Sulfides

Although anti-IgE antibody (Ab) therapy was recently shown to be effective in patients with bronchial asthma, no study has reported the effect of IgE therapy in the prevention of wasp venom anaphylaxis. In this study, we used a mouse model of wasp venom allergy to investigate the effect of anti-IgE Ab on wasp venom anaphylaxis.. We developed a mouse model of wasp venom allergy by intraperitoneally (i.p.) injecting wasp venom into BALB/c mice twice on experimental day (day) 0 and 7. On day 20, a group of mice received an i.p. injection of mouse anti-IgE Ab as a pretreatment, and another group received rat anti-IgG1 Ab. On day 21, the animals were challenged by i.p. injection of wasp venom, and 30 min later, body temperature was measured and serum levels of leukotriene (LT) B4 and LTC4 were determined using enzyme immunoassay.. The body temperature of mice treated with anti-IgE Ab and controls before and after wasp venom challenge was 37.8±0.2 vs 37.7± 0.3°C before challenge and 37.8±0.2 vs 37.1± 0.3°C after challenge, respectively, showing that anti-IgE Ab treatment significantly prevented body temperature from falling (p <0.05). Furthermore, anti-IgE Ab treatment reduced total serum IgE levels in the treated mice (42.2±15.9 pg/ml), compared with controls (105.9±23.1 pg/ml, p <0.05), and inhibited the secretion of LTC4 in the treated mice (32.0±18.8 pg/ml), but not in the controls (162.4±12.4 pg/ml, p <0.05), following challenge with wasp venom.. The results of the present study indicate that anti-IgE Ab treatment is an effective preventive measure against wasp venom-induced anaphylaxis.

Topics: Anaphylaxis; Animals; Body Temperature; Disease Models, Animal; Humans; Immunoglobulin E; Leukotriene B4; Leukotriene C4; Mice; Rats; Wasp Venoms

Through largely unknown mechanisms, Ca(2+) signaling plays important roles in vascular smooth muscle cell (VSMC) remodeling. Orai1-encoded store-operated Ca(2+) entry has recently emerged as an important player in VSMC remodeling. However, the role of the exclusively mammalian Orai3 protein in native VSMC Ca(2+) entry pathways, its upregulation during VSMC remodeling, and its contribution to neointima formation remain unknown.. The goal of this study was to determine the agonist-evoked Ca(2+) entry pathway contributed by Orai3; Orai3 potential upregulation and role during neointima formation after balloon injury of rat carotid arteries.. Ca(2+) imaging and patch-clamp recordings showed that although the platelet-derived growth factor activates the canonical Ca(2+) release-activated Ca(2+) channels via store depletion in VSMC, the pathophysiological agonist thrombin activates a distinct Ca(2+)-selective channel contributed by Orai1, Orai3, and stromal interacting molecule1 in the same cells. Unexpectedly, Ca(2+) store depletion is not required for activation of Orai1/3 channel by thrombin. Rather, the signal for Orai1/3 channel activation is cytosolic leukotrieneC4 produced downstream thrombin receptor stimulation through the catalytic activity of leukotrieneC4 synthase. Importantly, Orai3 is upregulated in an animal model of VSMC neointimal remodeling, and in vivo Orai3 knockdown inhibits neointima formation.. These results demonstrate that distinct native Ca(2+)-selective Orai channels are activated by different agonists/pathways and uncover a mechanism whereby leukotrieneC4 acts through hitherto unknown intracrine mode to elicit store-independent Ca(2+) signaling that promotes vascular occlusive disease. Orai3 and Orai3-containing channels provide novel targets for control of VSMC remodeling during vascular injury or disease.

Topics: Angioplasty, Balloon; Animals; Calcium Channels; Calcium Signaling; Carotid Artery Injuries; Cytosol; Disease Models, Animal; Leukotriene C4; Male; Membrane Glycoproteins; Muscle, Smooth, Vascular; Neointima; ORAI1 Protein; Patch-Clamp Techniques; Platelet-Derived Growth Factor; Rats; Rats, Sprague-Dawley; RNA, Small Interfering; Stromal Interaction Molecule 1; Thrombin

Although CD23-dependent transcytosis of IgE and IgE-derived immune complexes across respiratory epithelial cells is likely to play a pivotal role in the initiation and development of airway allergic inflammation, there is currently a lack of physiological support for this phenomena to suggest that the targeting of CD23 could be used as a means of therapeutic intervention. The present study was designed to detect the CD23 expression in the nasal mucosa of allergic rhinitis (AR) murine model by immunohistochemistry and western blotting, and to investigate whether intranasal anti-CD23 treatment could inhibit allergen-induced upper airway inflammation in the AR model. This is the first report to show that CD23 was constitutively expressed in murine nasal epithelial cells, and its expression was significantly up-regulated in the AR murine model. In vivo, the up-regulation of CD23 expression was correlated with increased serum IL-4 levels. Following intranasal anti-CD23 treatment, nasal symptoms were alleviated and histopathologic examination showed a significant decrease in eosinophilic infiltration. Meanwhile, ELISA analysis showed levels of serum leukotriene C4 (LTC4), eosinophil cation protein (ECP), ovalbumin (OVA)-specific IgE and IL-4 also significantly decreased, as were LTC4 and OVA-specific IgE in the nasal lavage fluid. Furthermore, Western blotting analysis showed that ECP expression in the nasal mucosa was down-regulated. Finally, flow cytometric analysis revealed anti-CD23 treatment inhibited Th2 cell responses. These results indicate that intranasal anti-CD23 treatment can reduce allergic responses in a murine model of allergic rhinitis.

Topics: Administration, Intranasal; Allergens; Animals; Budesonide; Disease Models, Animal; Down-Regulation; Eosinophil Cationic Protein; Eosinophils; Epithelial Cells; Female; Hypersensitivity; Immunoglobulin E; Inflammation; Interleukin-4; Leukotriene C4; Mice; Mice, Inbred BALB C; Nasal Mucosa; Ovalbumin; Random Allocation; Receptors, IgE; Rhinitis, Allergic; Rhinitis, Allergic, Perennial; Th2 Cells; Up-Regulation

Atopic dermatitis (AD) skin lesions exhibit epidermal and dermal thickening, eosinophil infiltration, and increased levels of the cysteinyl leukotriene (cys-LT) leukotriene C(4) (LTC(4)). Epicutaneous sensitization with ovalbumin of WT mice but not ΔdblGATA mice, the latter of which lack eosinophils, caused skin thickening, collagen deposition, and increased mRNA expression of the cys-LT generating enzyme LTC(4) synthase (LTC(4)S). Skin thickening and collagen deposition were significantly reduced in ovalbumin-sensitized skin of LTC(4)S-deficient and type 2 cys-LT receptor (CysLT(2)R)-deficient mice but not type 1 cys-LT receptor (CysLT(1)R)-deficient mice. Adoptive transfer of bone marrow-derived eosinophils from WT but not LTC(4)S-deficient mice restored skin thickening and collagen deposition in epicutaneous-sensitized skin of ΔdblGATA recipients. LTC(4) stimulation caused increased collagen synthesis by human skin fibroblasts, which was blocked by CysLT(2)R antagonism but not CysLT(1)R antagonism. Furthermore, LTC(4) stimulated skin fibroblasts to secrete factors that elicit keratinocyte proliferation. These findings establish a role for eosinophil-derived cys-LTs and the CysLT(2)R in the hyperkeratosis and fibrosis of allergic skin inflammation. Strategies that block eosinophil infiltration, cys-LT production, or the CysLT(2)R might be useful in the treatment of AD.

Topics: Adoptive Transfer; Animals; Cell Proliferation; Collagen; Dermatitis, Atopic; Dermis; Disease Models, Animal; Eosinophils; Fibrosis; GATA Transcription Factors; Glutathione Transferase; Humans; Immunization; Keratinocytes; Leukotriene C4; Mice; Ovalbumin; Receptors, Leukotriene; Signal Transduction; Skin

Lipoxin A(4) (LXA(4)), a biologically active eicosanoid with anti-inflammatory and pro-resolution properties, was recently found to have neuroprotective effects in brain ischemia. As 5-lipoxygenase (5-LOX) and leukotrienes are generally considered to aggravate cerebral ischemia/reperfusion (I/R) injury, we investigated their effects on LXA(4)-mediated neuroprotection by studying middle cerebral artery occlusion (MCAO)/reperfusion in rats and oxygen-glucose deprivation (OGD)/recovery in neonatal rat astrocyte primary cultures. LXA(4) effectively reduced infarct volumes and brain edema, and improved neurological scores in the MCAO/reperfusion experiments; this effect was partially blocked by butoxycarbonyl-Phe-Leu-Phe-Leu-Phe (Boc2), a specific antagonist of the LXA(4) receptor (ALXR). Total 5-LOX expression did not change, regardless of treatment, but LXA(4) could inhibit nuclear translocation induced by MCAO or OGD. We also found that LXA(4) inhibits the upregulation of both leukotriene B(4) (LTB(4)) and leukotriene C(4) (LTC(4)) and the phosphorylation of extracellular signal-regulated kinase (ERK) induced by MCAO or OGD. The phosphorylation of the 38-kDa protein kinase (p38) and c-Jun N-terminal kinase (JNK) was not altered throughout the experiment. These results suggest that the neuroprotective effects of LXA(4) are probably achieved by anti-inflammatory mechanisms that are partly mediated by ALXR and through an ERK signal transduction pathway.

Topics: Animals; Animals, Newborn; Arachidonate 5-Lipoxygenase; Astrocytes; Brain Edema; Brain Ischemia; Disease Models, Animal; Enzyme Inhibitors; Flavonoids; Glucose; Leukotriene B4; Leukotriene C4; Leukotrienes; Lipoxins; Male; MAP Kinase Signaling System; Neuroprotective Agents; Oxygen; Rats; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Messenger

The pathogenesis of aspirin-induced asthma (AIA) is presumed to involve the aspirin/non-steroidal anti-inflammatory drug (NSAID)-induced abnormal metabolism of arachidonic acid, resulting in an increase in 5-lipoxygenase (5-LO) metabolites, particularly leukotriene C(4) (LTC(4) ). However, the role of LTC(4) in the development of AIA has yet to be conclusively demonstrated.. The aim of this study was to evaluate the contribution of the lipid product LTC(4) secreted by the 5-LO pathway to the pathogenesis of AIA.. To evaluate antigen-induced airway inflammation, the concentrations of T-helper type 2 cytokine in bronchoalveolar lavage fluid (BALF) obtained from LTC(4) synthase-transgenic (Tg) and wild-type (WT) mice after challenge with ovalbumin were measured. Subsequently, the ex vivo and in vivo effects of the NSAID sulpyrine were investigated in these Tg and WT mice by measuring the secretion of LTC(4) from sulpyrine-treated BAL cells and the levels of LTC(4) in BALF following challenge with sulpyrine. Finally, the sulpyrine-induced airway response by the administration of pranlukast, an antagonist of the cysteinyl (cs)-LT1 receptor, was analysed.. The concentrations of IL-4, -5, and -13 in BALF from Tg mice were significantly higher than those in WT mice. In addition, sulpyrine augmented the secretion of LTC(4) in BALF and by BAL cells in Tg mice, but not in WT mice. Additionally, the increased airway resistance induced by sulpyrine could be reduced by treatment with pranlukast. Furthermore, the secretion of LTC(4) from mast cells, eosinophils, and macrophages was increased in the allergen-stimulated LTC(4) synthase gene Tg mice, even in the absence of sulpyrine, as well as in BAL cells after sulpyrine.. The over-expression of the LTC(4) synthase in a mouse asthma model also replicates the key features of AIA. And our study supports that cys-LTs play a major role in the pathogenesis of AIA in patients with chronic asthma.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Asthma, Aspirin-Induced; Dipyrone; Disease Models, Animal; Glutathione Transferase; Humans; Leukotriene C4; Mice; Mice, Transgenic; Ovalbumin

Hemorrhagic shock followed by resuscitation is conceived as an insult frequently induces a systemic inflammatory response syndrome and oxidative stress that results in multiple-organ dysfunction syndrome including acute lung injury. MK-886 is a leukotriene biosynthesis inhibitor exerts an anti inflammatory and antioxidant activity.. The objective of present study was to assess the possible protective effect of MK-886 against hemorrhagic shock-induced acute lung injury via interfering with inflammatory and oxidative pathways.. Eighteen adult Albino rats were assigned to three groups each containing six rats: group I, sham group, rats underwent all surgical instrumentation but neither hemorrhagic shock nor resuscitation was done; group II, Rats underwent hemorrhagic shock (HS) for 1 hr then resuscitated with Ringer's lactate (1 hr) (induced untreated group, HS); group III, HS + MK-886 (0.6 mg/kg i.p. injection 30 min before the induction of HS, and the same dose was repeated just before reperfusion period). At the end of experiment (2 hr after completion of resuscitation), blood samples were collected for measurement of serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The trachea was then isolated and bronchoalveolar lavage fluid (BALF) was carried out for measurement of leukotriene B4 (LTB4), leukotriene C4 (LTC4) and total protein. The lungs were harvested, excised and the left lung was homogenized for measurement of malondialdehyde (MDA) and reduced glutathione (GSH) and the right lung was fixed in 10% formalin for histological examination.. MK-886 treatment significantly reduced the total lung injury score compared with the HS group (P < 0.05). MK-886 also significantly decreased serum TNF-α & IL-6; lung MDA; BALF LTB4, LTC4 & total protein compared with the HS group (P < 0.05). MK-886 treatment significantly prevented the decrease in the lung GSH levels compared with the HS group (P < 0.05).. The results of the present study reveal that MK-886 may ameliorate lung injury in shocked rats via interfering with inflammatory and oxidative pathways implicating the role of leukotrienes in the pathogenesis of hemorrhagic shock-induced lung inflammation.

Topics: Acute Lung Injury; Animals; Disease Models, Animal; Indoles; Leukotriene B4; Leukotriene C4; Lipoxygenase Inhibitors; Male; Oxidative Stress; PPAR alpha; Rats; Shock, Hemorrhagic; Treatment Outcome

The aerial part of Saururus chinensis has been used in folk medicine to treat several inflammatory diseases in China and Korea. Previously, our group reported that anti-asthmatic activity of an ethanol extract of Saururus chinensis (ESC) might occur, in part, via the inhibition of prostaglandin D(2) (PGD(2)) and leukotriene C(4) (LTC(4)) production, and degranulation reaction in vitro, as well as through the down-regulation of interleukin (IL)-4 and eotaxin mRNA expression in an in vivo ovalbumin-sensitization animal model. However, the effects of Saururus chinensis on eicosanoid generation, as well as Th2 cytokines and eotaxin production in an in vivo asthma model, have not been fully investigated. Moreover, it has not been determined whether ESC can ameliorate airway inflammation in vivo. In the present study, we investigated the therapeutic activity of Saururus chinensis on ovalbumin (OVA)-sensitized airway inflammation and its major phytochemical compositions.. Asthma was induced in BALB/c mice by ovalbumin-sensitization and inhalation. ESC (10-100 mg/kg) or dexamethasone (5 mg/kg), a positive control, was administered 7 times orally every 12 h from one day before the first challenge to 1 h before the second challenge. The recruitment of inflammatory cells and hyperplasia of goblet cells were evaluated by H&E and PAS staining. Levels of Th2 cytokines, eotaxin, PGD(2) and LTC(4) were measured to evaluate the anti-inflammatory activity of ESC in OVA-sensitized mice. Contents of major components were analyzed by HPLC using a reversed-phase C18 column.. ESC (10 mg/kg) suppressed allergic airway inflammation by inhibition of the production of IL-4 (P<0.001), IL-5 (P<0.05), IL-13 (P<0.001), eotaxin (P<0.001), PGE(2) (P<0.001), LTC(4) (P<0.001) in lung extract and IgE level (P<0.001) in the serum. In addition, ESC (50 mg/kg) reduced the infiltration of inflammatory cells and hyperplasia of goblet cells in the lung tissues. The anti-inflammatory effect of ESC was comparable to that of the positive control drug, dexamethasone. Its major phytochemical composition includes manassantin A, B and sauchinone.. These results suggest that ESC decreased inflammation and mucus secretion in the OVA-induced bronchial asthma model, and its anti-asthmatic activity may occur in part via the inhibition of Th2 cytokines and eotaxin protein expression, as well as through prostaglandin E(2) (PGE(2)) and leukotriene C(4) (LTC(4)) generation. This effects may be attributed particularly to the presence of manassantin A, B and sauchinone major component evidenced by a HPLC analysis.

Topics: Animals; Asthma; Chromatography, High Pressure Liquid; Cytokines; Dinoprostone; Disease Models, Animal; Ethanol; Female; Hyperplasia; Immunoglobulin E; Leukotriene C4; Lung; Medicine, Korean Traditional; Mice; Mice, Inbred BALB C; Ovalbumin; Plant Components, Aerial; Plant Extracts; Respiratory Mucosa; Saururaceae

It has been well-documented that leukotrienes (LTs) are released in allergic lung inflammation and that they participate in the physiopathology of asthma. A role for LTs in innate immunity has recently emerged: Cys-LTs were shown to enhance FcgammaR-mediated phagocytosis by alveolar macrophages (AMs). Thus, using a rat model of asthma, we evaluated FcgammaR-mediated phagocytosis and killing of Klebsiella pneumoniae by AMs. The effect of treatment with a cys-LT antagonist (montelukast) on macrophage function was also investigated. Male Wistar rats were immunized twice with OVA/alumen intraperitoneally and challenged with OVA aerosol. After 24 h, the animals were killed, and the AMs were obtained by bronchoalveolar lavage. Macrophages were cultured with IgG-opsonized red blood cells (50:1) or IgG-opsonized K. pneumoniae (30:1), and phagocytosis or killing was evaluated. Leukotriene C(4) and nitric oxide were quantified by the EIA and Griess methods, respectively. The results showed that AMs from sensitized and challenged rats presented a markedly increased phagocytic capacity via FcgammaR (10X compared to controls) and enhanced killing of K. pneumoniae (4X higher than controls). The increased phagocytosis was inhibited 15X and killing 3X by treatment of the rats with montelukast, as compared to the non-treated group. cys-LT addition increased phagocytosis in control AMs but had no effect on macrophages from allergic lungs. Montelukast reduced nitric oxide (39%) and LTC(4) (73%). These results suggest that LTs produced during allergic lung inflammation potentiate the capacity of AMs to phagocytose and kill K. pneumonia via FcgammaR.

Topics: Acetates; Allergens; Animals; Asthma; Cyclopropanes; Cysteine; Disease Models, Animal; Klebsiella pneumoniae; Leukotriene Antagonists; Leukotriene C4; Leukotrienes; Lung; Macrophages, Alveolar; Male; Nitric Oxide; Ovalbumin; Phagocytosis; Pneumonia; Quinolines; Rats; Rats, Wistar; Receptors, IgG; Sulfides

Recent studies revealed that vasopressinergic neurons have a high content of cys-leukotriene C(4) (LTC(4)) synthase, a critical enzyme in cys-leukotriene synthesis that may play a role in regulating vasopressin secretion. This study investigates the role of this enzyme in arginine vasopressin (AVP) release during experimentally induced sepsis. Male Wistar rats received an i.c.v. injection of 3-[1-(p-chlorobenzyl)-5-(isopropyl)-3-tert-butylthioindol-2-yl]-2, 2-dimethylpropanoic acid (MK-886) (1.0 microg/kg), a leukotrienes (LTs) synthesis inhibitor, or vehicle, 1 h before cecal ligation and puncture (CLP) or sham operation. In one group of animals the survival rate was monitored for 3 days. In another group, the animals were decapitated at 0, 4, 6, 18 and 24 h after CLP or sham operation, and blood was collected for hematocrit, serum sodium and nitrate, plasma osmolality, protein and AVP determination. A third group was used for blood pressure measurements. The neurohypophysis was removed for quantification of AVP content, and the hypothalamus was dissected for LTC(4) synthase analysis by Western blot. Mortality after CLP was reduced by the central administration of MK-886. The increase in plasma AVP levels and hypothalamus LTC(4) synthase content in the initial phase of sepsis was blocked, whereas the decrease in neurohypophyseal AVP content was partially reversed. Also the blood pressure drop was abolished in this phase. The increase of serum nitric oxide and hematocrit was reduced, and the decrease in plasma protein and osmolality was not affected by the LTs blocker. In the final phase of sepsis, the plasma AVP level and the hypothalamic LTC(4) synthase content were at basal levels. The central administration of MK-886 increased the hypothalamic LTC(4) synthase content but did not alter the plasma and neurohypophysis AVP levels observed, or the blood pressure during this phase. These results suggest that the central LTs are involved in the vasopressin release observed during sepsis.

Topics: Animals; Arginine Vasopressin; Disease Models, Animal; Glutathione Transferase; Hematocrit; Hypotension; Hypothalamus; Indoles; Leukotriene C4; Leukotrienes; Lipoxygenase Inhibitors; Male; Nitric Oxide; Pituitary Gland, Posterior; Rats; Rats, Wistar; Sepsis

Oral cysteinyl-leukotriene (LT) receptor antagonists such as montelukast are used for reducing airway inflammation and exacerbations. However, inhaled therapy using LT receptor antagonists has not been studied. In the present study, the effect of inhaled montelukast was investigated on airway hyperresponsiveness measured by cysteinyl-LT induced bronchoconstriction in an animal model of asthma. Bronchoconstriction responses were induced by inhaled LTC4 and LTD4 (0.2 microg/ml each) or three doses of intravenous LTC4 and LTD4 (0.3, 1, 3 microg/kg) in ovalbumin (OVA)-sensitized Hartley male guinea-pigs. The response was measured by the change in peak pressure of airway opening (Pao). The effect of montelukast was evaluated by the comparison of bronchoconstriction responses between the groups of animals pre-treated with 15-min inhalation of 10mg/ml montelukast and saline. To evaluate the tissue injury which might be caused by montelukast inhalation, lung tissues were examined for the histology. The broncoconstriction responses induced by inhaled LTC4 and LTD4 were enhanced by OVA sensitization in the guinea-pigs. In sensitized animals, the significant increases in peak Pao were 18.5+/-2.1 cmH(2)O by LTC4 inhalation and 25.0+/-1.6 cmH(2)O by LTD4 inhalation on average. Prior treatment of inhaled montelukast potently suppressed the peak Pao increases induced by both inhaled and intravenous LTC4 and LTD4 (all P<0.01 vs. saline control). Moreover, the suppression of inhaled montelukast against LTD4-induced bronchoconstriction was observed for at least up to 24h. According to the histological examination, montelukast inhalation produced no injury to the lung tissue. Inhaled montelukast, a cysteinyl-LT receptor antagonist, was effective in inhibiting cysteinyl-LT-induced acute bronchoconstriction, and may have the potential for clinical use as a new asthma drug.

Topics: Acetates; Administration, Inhalation; Animals; Asthma; Bronchial Hyperreactivity; Bronchoconstriction; Cyclopropanes; Cysteine; Disease Models, Animal; Guinea Pigs; Immunologic Factors; Leukotriene Antagonists; Leukotriene C4; Leukotriene D4; Leukotrienes; Lung; Male; Ovalbumin; Quinolines; Sulfides

The leukotrienes belong to a family of biologically active lipids derived from arachidonate that are often involved in inflammatory responses. In the central nervous system, a group of leukotrienes, known as the cysteinyl leukotrienes, is generated in brain tissue in response to a variety of acute brain injuries. Although the exact clinical significance of this excess production remains unclear, the cysteinyl leukotrienes may contribute to injury-related disruption of the brain-blood barrier and exacerbate secondary injury processes. In the present study, the formation and role of cysteinyl leukotrienes was explored in the fluid percussion injury model of traumatic brain injury in rats. The results showed that levels of the cysteinyl leukotrienes were elevated after fluid percussion injury with a maximal formation 1 hour after the injury. Neutrophils contributed to cysteinyl leukotriene formation in the injured brain hemisphere, potentially through a transcellular biosynthetic mechanism. Furthermore, pharmacological reduction of cysteinyl leukotriene formation after the injury, using MK-886, resulted in reduction of brain lesion volumes, suggesting that the cysteinyl leukotrienes play an important role in traumatic brain injury.

Topics: Animals; Brain Injuries; Chromatography, Liquid; Cysteine; Disease Models, Animal; Enzyme Inhibitors; Indoles; Leukotriene B4; Leukotriene C4; Leukotriene D4; Leukotriene E4; Leukotrienes; Male; Mass Spectrometry; Neutrophils; Rats; Rats, Sprague-Dawley

To investigate the expression and activity of leukotriene C4 (LTC4) synthesis enzymes and their underlying relationship with cysteinyl leukotriene (cys-LT) generation in a rat fulminant hepatic failure (FHF) model induced by D-galactosamine/lipopolysaccharide (D-GalN/ LPS).. Rats were treated with D-GalN (300 mg/kg) plus LPS (0.1 mg/kg) for 1, 3, 6, and 12 h. Enzyme immunoassay was used to determine the hepatic cys-LT content. Reverse transcription-polymerase chain reaction (RT-PCR), Western blot or immunohistochemical assay were employed to assess the expression or location of LTC4 synthesis enzymes, which belong to membrane associated proteins in eicosanoid and glutathione (MAPEG) metabolism superfamily. Activity of LTC4 synthesis enzymes was evaluated by determination of the products of LTA4 after incubation with liver microsomes using high performance liquid chromatography (HPLC).. Livers were injured after treatment with D-GalN/LPS, accompanied by cys-LT accumulation at the prophase of liver injury. Both LTC4 synthase (LTC4S) and microsomal glutathione-S-transferase (mGST) 2 were expressed in the rat liver, while the latter was specifically located in hepatocytes. Their mRNA and protein expressions were up-regulated at an earlier phase after treatment with D-GalN/LPS. Meantime, a higher activity of LTC4 synthesis enzymes was detected, although the activity of LTC4S played the main role in this case.. The expression and activity of both LTC4S and mGST2 are up regulated in a rat FHF model, which are, at least, partly responsible for cys-LT hepatic accumulation.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Blotting, Western; Chromatography, High Pressure Liquid; Cysteine; Disease Models, Animal; Galactosamine; Glutathione Transferase; Immunohistochemistry; Isoenzymes; Leukotriene C4; Leukotrienes; Lipopolysaccharides; Liver; Liver Failure, Acute; Male; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Up-Regulation

Cyclooxygenases (COXs) play important roles in inflammation and carcinogenesis. The present study aimed to determine the effects of COX-1 and COX-2 gene disruption on Helicobacter pylori-induced gastric inflammation.. Wild-type (WT), COX-1 and COX-2 heterozygous (COX-1+/- and COX-2+/-), and homozygous COX-deficient (COX-1-/- and COX-2-/-) mice were inoculated with H. pylori strain TN2 and killed after 24 weeks of infection. Uninfected WT and COX-deficient mice were used as controls. Levels of gastric mucosal inflammation, epithelial cell proliferation and apoptosis, and cytokine expression were determined.. COX deficiency facilitated H. pylori-induced gastritis. In the presence of H. pylori infection, apoptosis was increased in both WT and COX-deficient mice, whereas cell proliferation was increased in WT and COX-1-deficient, but not in COX-2-deficient, mice. Tumor necrosis factor (TNF)-alpha and interleukin-10 mRNA expression was elevated in H. pylori-infected mice, but only TNF-alpha mRNA expression was further increased by COX deficiency. Prostaglandin E2 levels were increased in infected WT and COX-2-deficient mice but were at very low levels in infected COX-1-deficient mice. Leukotriene (LT) B4 and LTC4 levels were increased to a similar extent in infected WT and COX-deficient mice.. COX deficiency enhances H. pylori-induced gastritis, probably via TNF-alpha expression. COX-2, but not COX-1, deficiency suppresses H. pylori-induced cell proliferation.

Topics: Animals; Apoptosis; Cell Proliferation; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Gastric Mucosa; Gastritis; Gene Expression Regulation; Helicobacter Infections; Helicobacter pylori; Interleukin-10; Leukotriene B4; Leukotriene C4; Mice; Mice, Inbred C57BL; Mice, Knockout; RNA, Messenger; Tumor Necrosis Factor-alpha

During an asthmatic episode, leukotriene C4 (LTC4) and interleukin 13 (IL-13) are released into the airways and are thought to be central mediators of the asthmatic response. However, little is known about how these molecules interact or affect each other's signaling pathway.. To determine if the LTC4 and IL-13 signaling pathways interact with each other's pathways.. We examined airway responsiveness, cysteinyl LTs (Cys-LTs), and Cys-LT and IL-13 receptor transcript levels in wild-type mice and in mice that were deficient in gamma-glutamyl leukotrienase (an enzyme that converts LTC4 to LTD4), STAT6 (signal transducer and activator of transcription 6 [a critical molecule in IL-13 signaling]), and IL-4Ralpha (a subunit of the IL-13 receptor).. Wild-type (C57BL/129SvEv) and gamma-glutamyl leukotrienase-deficient mice showed increased airway responsiveness after intranasal instillation of IL-13; similar results were observed after intranasal instillation of IL-13 or LTC4 in a second wild-type strain (BALB/c). Interleukin 13 treatment reduced levels of Cys-LTs in bronchoalveolar lavage fluid. This change was unaccompanied by changes in other arachidonic acid metabolites or in RNA transcript levels of enzymes associated with Cys-LT synthesis. Interleukin 13 treatment also increased transcript levels of the Cys-LT 1 and Cys-LT 2 receptors, while LTC4 increased transcript levels of the alpha1 chain of the IL-13 receptor. Furthermore, IL-4Ralpha-deficient mice had increased airway responsiveness to LTC4 but not to IL-13, whereas STAT6-deficient mice failed to respond to either agonist.. These findings indicate that LTC4 and IL-13 are dependent on or signal through STAT6 to increase airway responsiveness and that both agonists regulate expression of each other's receptors.

Topics: Airway Resistance; Animals; Asthma; Bronchoalveolar Lavage Fluid; Dipeptidases; Disease Models, Animal; Humans; Interleukin-13; Interleukin-13 Receptor alpha1 Subunit; Leukotriene C4; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Receptors, Interleukin; Receptors, Interleukin-13; Receptors, Interleukin-4; Receptors, Leukotriene; Recombinant Proteins; RNA, Messenger; Signal Transduction; STAT6 Transcription Factor

Both nitric oxide (NO) and prostaglandins have been proposed as inhibitor substances involved in collagen deposition in the hepatic parenchyma. The possible reciprocal connections between NO and eicosanoids in the development of liver fibrosis were investigated during the initial phase of common bile duct obstructions.. A total of 30 male albino guinea pigs were randomly and equally assigned to three groups. Group 1 underwent sham laparotomy. Group 2 and group 3 were subjected to permanent common bile duct ligature for 24 and 72 h, respectively. Changes in the liver prostaglandin E(2) (PGE(2)), leukotriene C(4), malondialdehyde contents and plasma nitrite plus nitrate concentrations were measured. To evaluate the extent of hepatic fibrosis, histological assessment of liver was confirmed with the equivalent hydroxyproline contents of liver.. Twenty-four hours after ligature, the amount of malondialdehyde and PGE(2) and plasma nitrite plus nitrate concentrations increased significantly, whereas liver hydroxyproline contents did not change. However, 72 h after ligature (Group 3), lipid peroxidation and collagen deposition were significantly higher than that of the group 2 animals. The PGE(2) : leukotriene C(4) ratio peaked at 24 h and later decreased, whereas PGE(2) : NO ratio remained unchanged in both group 2 and group 3 animals.. The initiation of collagen synthesis occurred in portal tract as early as within the first 72 h of bile duct obstruction. The optimum function of reactive oxygen species on the stellate cell activation might be determined by the interaction between NO and PGE(2).

Topics: Animals; Cell Proliferation; Cholestasis; Collagen; Common Bile Duct Diseases; Dinoprostone; Disease Models, Animal; Disease Progression; Guinea Pigs; Leukotriene C4; Liver; Liver Cirrhosis; Male; Malondialdehyde; Nitrates; Nitrites

Inhalation of heparin attenuates hyperventilation-induced bronchoconstriction in humans and dogs. The purpose of this study was to determine whether heparin inhibits the late-phase response to hyperventilation, which is characterized by increased peripheral airway resistance (RP), eicosanoid mediator production, neutrophilic/ eosinophilic inflammation, and airway hyperreactivity (AHR) at 5 h after dry air challenge (DAC). Fiberoptic bronchoscopy was used to record RP and airway reactivity (DeltaRP) to aerosol and intravenous histamine before and 5 h after DAC. Bronchoalveolar lavage fluid (BALF) cells and eicosanoid mediators were also measured approximately 5 h after DAC. DAC of vehicle-treated bronchi resulted in late-phase airway obstruction (approximately 120% increase over baseline RP), inflammation, increased BALF concentrations of leukotriene (LT) C(4), LTD(4), and LTE(4) and prostaglandin (PG)D(2), and AHR. Pretreatment with aerosolized heparin attenuated late-phase airway obstruction by approximately 50%, inhibited eosinophil infiltration, reduced BALF concentrations of LTC(4), LTD(4), and LTE(4) and PGD(2), and abolished AHR. We conclude that heparin inhibits hyperventilation-induced late-phase changes in peripheral airway function, and does so in part via the inhibition of eosinophil migration and eicosanoid mediator production and release.

Topics: Administration, Inhalation; Airway Resistance; Animals; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Bronchoscopy; Disease Models, Animal; Dogs; Drug Evaluation, Preclinical; Eicosanoids; Eosinophils; Heparin; Humans; Hyperventilation; Inflammation; Leukotriene C4; Leukotriene D4; Leukotriene E4; Male; Neutrophils; Prostaglandin D2; Time Factors

Airway hyperresponsiveness (AHR) is one of the characteristic features of human asthma. The presence of AHR and the precise mechanisms immediately after establishment of sensitization in guinea pigs are unclear, although there are many reports showing allergen exposure that causes an increase in bronchial responsiveness associated with eosinophil influx into the airway in sensitized guinea pigs.. We investigated the inhibitory effects on AHR to histamine of ONO-1078, a leukotriene antagonist; indomethacin, a cyclooxygenase inhibitor; S-145, a thromboxane A(2) (TXA(2)) antagonist, and Y-24180, a platelet-activating factor (PAF) antagonist, to assess the involvement of chemical mediators in AHR employing ovalbumin (OA) sensitized guinea pig models.. Male Hartley guinea pigs were used. Each group comprised 4-7 animals. The animals were sensitized to OA, injecting intraperitoneally 30 mg of cyclophosphamide and 2,000 microg of OA together with 100 mg of aluminum hydroxide as the adjuvant. The guinea pigs were artificially ventilated via a cannula using a small-animal respirator after intraperitoneal anesthesia with pentobarbital sodium for tracheotomy. The pressure at the airway opening (PAO) was measured using a differential pressure transducer, and a differential pressure of peak PAO (peak DeltaPAO) at inspiratory phase as an overall index of bronchial response to bronchoactive agents was used. While being artificially ventilated, the animals were exposed to physiological saline solution containing various concentrations of histamine (4.9, 9.8, 20, 39, 78, and 156 microg/ml) by inhalation for 30 s at 3-min intervals. Determinations were made at 1 min after each inhalation. The chemical mediators were each (30 mg/kg of ONO-1078, 3 mg/kg of S-1452, and 1 mg/kg of Y-24180) administered orally to sensitized guinea pigs, and the airway response to histamine was assessed. Each group comprised 4-7 animals.. The airway response to histamine was significantly greater in the sensitized group than in the nonsensitized group at histamine concentrations of 36 (p < 0.05), 78, and 156 mg/ml (p < 0.01). Leukotrienes C(4) and D(4): 30 mg/kg of ONO-178 did not show any inhibitory effect on airway response to inhaled histamine. Cyclooxygenase: 5 mg/kg of indomethacin did not show any inhibitory effect on the airway response to inhaled histamine. TXA(2): the AHR to inhaled histamine at doses of 9.8, 39, 78, and 156 microg/ml was significantly inhibited by prior administration of 3 mg/kg of S-1452. PAF: the AHR to inhaled histamine at doses of 9.8, 39, and 78 microg/ml was significantly inhibited by prior administration of 1 mg/kg of Y-24180.. S-1452 (3 mg/kg) and Y-24180 (1 mg/kg) significantly inhibited AHR to histamine, while ONO-108 (30 mg/kg) and indomethacin (5 mg/kg) did not. The results suggest that TXA(2) and PAF are involved in AHR in OA-sensitized guinea pigs.

Topics: Airway Resistance; Animals; Asthma; Bronchial Hyperreactivity; Disease Models, Animal; Dose-Response Relationship, Drug; Guinea Pigs; Histamine; Indomethacin; Leukotriene C4; Leukotriene D4; Male; Ovalbumin; Platelet Activating Factor; Probability; Reference Values; Sensitivity and Specificity; Thromboxane A2

Leukocyte rolling is recognized as an important event in facilitating the extravasation of leukocytes from the vascular to the interstitial compartment, and is mediated by the selectin family of cell adhesion molecules. The aim of this study was to evaluate and characterize the rolling behavior of leukocytes in a model of acute inflammation using a novel soluble selectin ligand directed against P-selectin.. Feline mesenteric postcapillary venules were visualized using intravital microscopy prior to and following exposure to leukotriene C4 (LTC4) in animals pretreated with vehicle (saline) and the P-selectin antagonist rPSGL-Ig.. A concentration of 500 pM LTC4 induced a threefold and sixfold elevation in leukocyte rolling flux and adhesion, respectively, compared to baseline values (p < 0.05). Administration of rPSGL-Ig had no effect on LTC4-induced leukocyte rolling flux but significantly attenuated the increase in the fraction of rolling leukocytes (p < 0.05). In addition, rPSGL-Ig inhibited the LTC4-induced reductions in leukocyte rolling velocity (p < 0.001). Finally, LTC4-induced leukocyte adhesion in animals pretreated with rPSGL-Ig was reduced by 60%, compared to vehicle-treated animals (p < 0.05).. LTC4 induces leukocyte rolling and adhesion in feline mesenteric venules in a dose-dependent manner. Administration of rPSGL-Ig inhibits LTC4-induced reductions in leukocyte rolling velocity and attenuates the elevation in the fraction of rolling leukocytes produced by LTC4 stimulation. This suggests that rPSGL-Ig may be used to reduce leukocyte rolling and adhesion, and subsequently attenuate tissue injury during inflammation.

Topics: Amino Acid Sequence; Animals; Cats; Cell Adhesion; Cell Movement; Disease Models, Animal; Humans; Inflammation; Leukocytes; Leukotriene C4; Male; Membrane Glycoproteins; Mesenteric Veins; Molecular Sequence Data; P-Selectin; Phlebitis; Recombinant Proteins; Solubility; Venules

A prospective, randomized, blinded experimental trauma study.. The effect of adenosine on arachidonic acid metabolites and lipid peroxidation was investigated in induced spinal cord injury.. Effects of adenosine in ischemia-reperfusion models have been studied, but no studies of adenosine's effect on direct trauma to the spinal cord have been reported.. Thirty-seven adult Wistar albino rats were randomly divided into four groups and underwent laminectomy. Group 1 underwent a sham operation. Group 2 received an intravenous adenosine infusion of 100 micrograms/kg per minute for 30 minutes. In Group 3, a standard spinal cord trauma of 50 g.cm strength was established at the lower thoracic level with a "weight-drop" technique, and Group 4 received an infusion of adenosine (100 micrograms/kg per minute) for 30 minutes after the trauma.. Tissue prostaglandin E2 activity was significantly higher in adenosine-treated trauma groups when compared with that in other groups (P < 0.0001). The difference in tissue leukotriene C4 activity between control and trauma groups was significant (P < 0.05). Adenosine infusion after trauma limited the increases in lipid peroxidation, with the difference approaching significance at P = 0.06. The structure of myelin was well preserved in the adenosine-treated trauma group. However, the changes were irreversible in severely damaged areas.. After acute spinal cord trauma, intravenous adenosine infusion of 100 micrograms/kg per minute could attenuate progression to secondary injury, but adenosine alone was not effective yet.

Topics: Acute Disease; Adenosine; Animals; Arachidonic Acid; Dinoprostone; Disease Models, Animal; Laminectomy; Leukotriene C4; Lipid Peroxidation; Male; Myelin Sheath; Nerve Compression Syndromes; Random Allocation; Rats; Rats, Wistar; Spinal Cord; Spinal Cord Injuries; Vasodilator Agents

The aim of this study was to investigate the cytoprotective effect of Iloprost on the liver against carbon tetrachloride induced necrosis. The serum histamine-like activity was found to be increased when compared with that of controls after treatment with carbon tetrachloride for 18 weeks while prostaglandin E2- and leukotriene C4-like activities were unchanged. After pretreatment with Iloprost for 18 weeks the increased activity of histamine was found to be unchanged while prostaglandin E2-like activity was increased. It is concluded that Iloprost protects the liver against carbon tetrachloride-induced damage and reduces the level of histamine that has a role in the pathogenesis of portal hypertension.

Topics: Animals; Carbon Tetrachloride; Dinoprostone; Disease Models, Animal; Female; Histamine; Hypertension, Portal; Iloprost; Injections, Subcutaneous; Leukotriene C4; Liver; Liver Cirrhosis, Experimental; Male; Platelet Aggregation Inhibitors; Rats; Vasodilator Agents

To elucidate the mechanism of development of asthma, we tried to develop a model which elicited a late asthmatic response by a combination of systemic and inhaled sensitization with ovalbumin in guinea pigs. Eighty-seven percent of animals elicited both an immediate and late asthmatic response after the third antigen inhalation. Airway eosinophilia and airway hyperresponsiveness (AHR) induced after the third challenge were more severe than those after the first challenge. There was a good correlation between airway eosinophilia and AHR in this model under experimental modulation of the number of eosinophils, such as by interleukin 5 or antieosinophil antibody injection. These results demonstrate that eosinophils play an important role in the development of late asthmatic response and AHR.

Topics: Animals; Antibodies; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Bronchoconstrictor Agents; Disease Models, Animal; Eosinophils; Guinea Pigs; Histamine; Interleukin-5; Leukocyte Count; Leukotriene C4; Male; Methacholine Chloride; Ovalbumin; Passive Cutaneous Anaphylaxis; Pulmonary Eosinophilia; Thromboxane B2; Time Factors

Topics: Animals; Asthma; Cyclosporine; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Freund's Adjuvant; Guinea Pigs; Histamine Release; Immunosuppressive Agents; Leukotriene C4; Leukotriene D4; Leukotriene E4; Male; Muscle Contraction; Muscle, Smooth; Ovalbumin; Radioimmunoassay; Trachea

We analyzed fatty acid make up of cells and organs from autoimmune and immunologically normal mice to determine whether intrinsic differences in composition might be associated with an inflammatory phenotype. Macrophages (MO) isolated from 4-6-week-old MRL lpr/lpr mice were cultured with phorbol ester (PMA), fibroblast growth factor-1 (FGF-1), fibroblast growth factor-2 (FGF-2) and medium control to determine whether these cell signals might induce membrane fatty acid changes. Individual phospholipid analysis showed 8.4- and 5.1-fold increases in phosphatidylcholine arachidonate (20:4) mole % over baseline values following culture with FGF-1 and FGF-2, respectively. Unfractionated analysis on kidney and liver extracts from 4-6 week MRL lpr/lpr, 16-20 week lpr and 12-20 week MRL +/-/+/- mice demonstrated no significant intrastrain fatty acid differences. Higher levels of 20:4 in 4-6 week lpr mice were noted compared to 16-20 week lpr or +/+ mice in kidney, and liver samples (P < 0.05). It is possible that membrane changes precipitated by microenvironmental cytokine concentrations may contribute to the expression of autoimmune disease in this model.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Autoimmune Diseases; Disease Models, Animal; Fatty Acids; Fibroblast Growth Factor 1; Fibroblast Growth Factor 2; Kidney; Leukotriene C4; Liver; Macrophages, Peritoneal; Membrane Lipids; Mice; Mice, Inbred MRL lpr; Phospholipids; Tetradecanoylphorbol Acetate

Inhalation of antigen in immunized mice induces an infiltration of eosinophils into the airways and increased bronchial hyperreactivity as are observed in human asthma. We employed a model of late-phase allergic pulmonary inflammation in mice to address the role of leukotrienes (LT) in mediating airway eosinophilia and hyperreactivity to methacholine. Allergen intranasal challenge in OVA-sensitized mice induced LTB4 and LTC4 release into the airspace, widespread mucus occlusion of the airways, leukocytic infiltration of the airway tissue and broncho-alveolar lavage fluid that was predominantly eosinophils, and bronchial hyperreactivity to methacholine. Specific inhibitors of 5-lipoxygenase and 5-lipoxygenase-activating protein (FLAP) blocked airway mucus release and infiltration by eosinophils indicating a key role for leukotrienes in these features of allergic pulmonary inflammation. The role of leukotrienes or eosinophils in mediating airway hyperresponsiveness to aeroallergen could not be established, however, in this murine model.

Topics: 5-Lipoxygenase-Activating Proteins; Allergens; Animals; Asthma; Bronchial Provocation Tests; Bronchoconstrictor Agents; Carrier Proteins; Disease Models, Animal; Female; Immunoglobulin E; Inflammation; Leukotriene B4; Leukotriene C4; Lipoxygenase Inhibitors; Membrane Proteins; Methacholine Chloride; Mice; Mice, Inbred BALB C; Mucus; Ovalbumin; Pulmonary Eosinophilia; Respiratory Function Tests; Respiratory System

To study the asthmatogenic effect of certain airborne elements of the home environment, we studied a group of guinea pigs exposed to aerosolized cockroach allergen (CRa) and side-stream cigarette (S-SC) smoke. Four groups of guinea pigs were exposed to aerosols, either saline or CRa, for 4 weeks, after a sham or S-SC smoke pretreatment. Anaphylactic antibodies were measured by passive cutaneous anaphylaxis (PCA) assay and by skin test. Animals were challenged with aerosol CRa on day 35, and lung function and leukotrienes (LTB4 and LTC4/D4) were measured. Skin tests were positive on days 21 and 29. The antibodies were heat-stable, IgG1a-like antibodies (PCA titers 1:2-18). The CRa challenge caused an immediate reduction in both the maximal expiratory flow rate at 50% of the lung capacity and respiratory compliance. The decreased lung function continued for up to 6 h (p < 0.0001). LTB4 and LTC4/D4 were elevated (p < 0.0001) in the sensitized animals at the corresponding times of reduced lung function. S-SC smoke did not affect the CRa sensitization; instead, a protective effect on the CRa-induced bronchospasms was noted. Thus, the study indicates that a simple airborne CRa exposure without an adjuvant sensitizes guinea pigs, and that the animals respond to antigen challenge with CRa-specific airway obstructions.

Topics: Aerosols; Air Pollution, Indoor; Allergens; Animals; Asthma; Cockroaches; Disease Models, Animal; Environmental Exposure; Guinea Pigs; Immunoglobulin G; Leukotriene B4; Leukotriene C4; Leukotriene D4; Lung; Male; Passive Cutaneous Anaphylaxis; Respiratory Function Tests; Skin Tests; Tobacco Smoke Pollution

To disclose the cytoprotective mechanism of 1,6-dihydro-2[2-(2-methyoxypropoxy)anilino]-6-oxo-5-pyrimidinecarb oxylic acid (CAS 98772-05-5, MAR-99), the effect of this compound on the microvascular injury in gastric mucosa induced by 99.5% ethanol in rats was studied. In this experiment, it was found that the elevation of vascular permeability observed at the early state of ethanol-induced gastric mucosal injury was closely correlated with the combined action of histamine and slow reacting substance (leukotriene C4, LTC4). MAR-99 (0.3-10 mg/kg p.o.) prevented dose-dependently the increase in vascular permeability. Furthermore, MAR-99 (10 mg/kg p.o.) improved the decrease in the number of histamine containing cells and histamine content, and prevented the production of LTC4. These results suggest that MAR-99 exerts its anti-microvascular injury effect by regulating the release of histamine and the production of LTC4 in glandular stomach against ethanol, and this effect may contribute to the anti-lesion effect of this compound.

Topics: Animals; Anti-Ulcer Agents; Capillary Permeability; Disease Models, Animal; Ethanol; Gastric Mucosa; Guinea Pigs; Histamine Release; Leukotriene C4; Male; Pyrimidines; Rats; Rats, Sprague-Dawley; Tranexamic Acid

We have investigated the effects of actinomycin D on mouse ear oedema induced by capsaicin, neuropeptides, and established inflammatory mediators. Actinomycin D (0.5 mg/kg, i.v.) significantly (P < 0.01) inhibited ear oedema induced by topical application of capsaicin, while adriamycin (6.0 mg/kg, i.v.) and cycloheximide (6.0 mg/kg, i.v.) had no effect on oedema. The ear oedema induced by intradermal injection of neuropeptides such as mammalian tachykinins, calcitonin gene-related peptide (CGRP), and vasoactive intestinal peptide (VIP), was markedly (P < 0.05, P < 0.01 or P < 0.001) suppressed by actinomycin D. The drug was also effective (P < 0.01 or P < 0.001) in inhibiting bradykinin (BK)- and compound 48/80-induced ear oedema, but did not inhibit oedema induced by histamine, 5-HT, leukotriene C4 (LTC4), and platelet activating factor (PAF) at a dose of 1 mg/kg. In mast cell-deficient W/WV mice, actinomycin D (1.0 mg/kg, i.v.) failed to inhibit substance P (SP)-induced ear oedema whereas spantide (0.5 mg/kg, i.v.) was an effective (P < 0.01) inhibitor of oedema formation. Furthermore, actinomycin D (10-100 microM) dose-dependently prevented histamine release from rat peritoneal mast cells evoked by SP, compound 48/80, and the ionophore A23182, respectively. These results strongly suggest that an inhibitory effect of actinomycin D on neurogenic inflammation is due primarily to the prevention of mast cell activation mediated by neuropeptides, rather than an interaction with DNA or receptors of neuropeptides.

Topics: Animals; Bradykinin; Calcimycin; Calcitonin Gene-Related Peptide; Capsaicin; Cycloheximide; Dactinomycin; Disease Models, Animal; Dose-Response Relationship, Drug; Doxorubicin; Ear Diseases; Edema; Histamine; Injections, Intravenous; Leukotriene C4; Male; Mast Cells; Mice; p-Methoxy-N-methylphenethylamine; Platelet Activating Factor; Rats; Rats, Wistar; Serotonin; Substance P; Tachykinins; Vasoactive Intestinal Peptide

TEMPOL, a cyclic nitroxide stable radical blocks biological damage by breaking chain reactions through termination reaction with free radicals, and by inhibiting the catalytic effect of transition metals. This study tested its protective effect on two models of experimental colitis as free radicals play an important part in their pathogenesis. TEMPOL was given intragastrically immediately after induction of colitis with acetic acid or trinitrobenzene sulphonic acid (TNB) and mucosal damage was assessed one, three, or seven days later. Cellular partition of TEMPOL was determined by electron paramagnetic resonance spectroscopy. In vitro experiments showed that TEMPOL immediately penetrates colonic mucosa and, following its intragastric administration, it persists in both gastric and colonic mucosa for several hours. Intragastric administration of TEMPOL, 0.5 g/kg/bw, immediately after intracaecal administration of 5% acetic acid significantly decreased mucosal lesion area, myeloperoxidase activity, and leukotriene B4 and C4 generation when assessed 24 hours after damage induction. Intragastric administration of TEMPOL, 0.5 g/kg/bw, immediately after intracolonic administration of 30 mg TNB in 0.25 ml 50% ethanol, and once daily thereafter, significantly decreased mucosal lesion area assessed after one, three, and seven days, having no effect on LTC4 generation and affecting colonic weight, myeloperoxidase activity, and LTB4 generation only sporadically. In conclusion, TNB and acetic acid induced colitis can be pharmacologically manipulated by TEMPOL. TEMPOL may be beneficial in the treatment or prevention of inflammatory bowel disease.

Topics: Acetates; Animals; Antioxidants; Colitis; Cyclic N-Oxides; Disease Models, Animal; Electron Spin Resonance Spectroscopy; Intestinal Mucosa; Leukotriene B4; Leukotriene C4; Lipoxygenase; Male; Peroxidase; Rats; Rats, Sprague-Dawley; Spin Labels; Time Factors; Trinitrobenzenesulfonic Acid

We examined the effects of eicosanoid antagonists on colonic damage induced by trinitrobenzene sulfonic acid (TNB) in a rat inflammatory bowel model. TNB (30 mg) dissolved in 0.25 ml of 50% ethanol, was given intrarectally. The appropriate doses of ONO-1078 (a leukotriene C4D4 antagonist), ONO-4057 (a leukotriene B4 antagonist), and OKY-046 (a thromboxane A2 synthetase inhibitor) were given to obtain the same blood level, either 4 h before (pre-treatment model) or 24 h after (the post-treatment model) the administration of TNB (n = 8 in all groups). Drugs were given once daily for 6 days through a gastric feeding tube. Autopsy was performed on the 7th day. Colonic damage was assessed in terms of colonic damage scores, and myeloperoxidase (MPO) activity and eicosanoid concentrations in colonic tissues were measured. Compared with the group given TNB alone, the colonic damage score was reduced to 10% in the pre-treatment model with ONO-1078, but the score was not reduced in other groups, MPO activity was not changed in any group. The concentration of leukotriene C4 was reduced with ONO-1078 treatment, in both pre- and post-treatment models. These results demonstrated that a leukotriene C4D4 antagonist reduced colonic inflammation; however, its anti-inflammatory effect was limited in this colitis model.

Topics: Animals; Chromones; Colon; Disease Models, Animal; Eicosanoids; Female; Inflammatory Bowel Diseases; Leukotriene C4; Leukotriene D4; Methacrylates; Peroxidase; Phenylpropionates; Rats; Rats, Sprague-Dawley; SRS-A; Thromboxane-A Synthase; Trinitrobenzenesulfonic Acid

The involvement of cysteinyl leukotrienes (LT) in the etiology of glomerulonephritis (GN) was investigated in a rat model of nephrotoxic serum nephritis in which renal function, morphology, LTC4 synthase activity and urinary cysteinyl LT excretion were monitored over seven days. Significant alterations in renal function and morphology were evident on day 1 in nephritic rats, with a 12% decline in creatinine clearance, a greater than three-fold increase in urinary protein excretion and histologic evidence of basement membrane thickening. Urinary LTC4 excretion in the nephritic rats was elevated at this time to 140 +/- 38 pg/hr (P < 0.01) compared to undetectable levels in control animals. On days 3 and 7, while proteinuria intensified and glomerular filtration remained depressed, LTC4 excretion declined 14% (NS) and 79% (P < 0.05), respectively. The temporal changes in urinary LTC4 excretion were paralleled by concomitant alterations in LTC4 synthase activity in renal cortical microsomes, where an 84% (P < 0.01) drop in enzyme activity occurred from day 1 to day 7 in the nephritic group. This data provides the first measurement of urinary cysteinyl LT excretion and altered LTC4 synthase activity in a model of experimental GN and supports an early role for LT's in the development of subsequent functional changes.

Topics: Animals; Disease Models, Animal; Glomerulonephritis; Glutathione Transferase; Kidney; Kidney Cortex; Leukotriene C4; Leukotriene D4; Leukotriene E4; Male; Microsomes; Rats; Rats, Sprague-Dawley