verlukast and Disease-Models--Animal

Hepatopulmonary syndrome (HPS) is the major complication subsequent to liver ischemia and reperfusion (I/R) injury after resection or transplantation of liver. Hallmarks of HPS include increases in pulmonary leukotrienes and neutrophil recruitment and infiltrating across capillaries. We aimed to investigate the protective efficacy of MK-571, a multidrug resistance-associated protein 1 inhibitor and leukotriene D4 agonist, against hepatic I/R injury-associated change in capillary filtration.. Eighteen Sprague-Dawley male rats were evenly divided into a sham-operated group, a hepatic I/R group, and an MK-571-treated I/R group. MK-571 was administered intraperitoneally 15 min before hepatic ischemia and every 12 hours during reperfusion. Ischemia was conducted by occluding the hepatic artery and portal vein for 30 min, followed by removing the clamps and closing the incision. Forty-eight hours after hepatic ischemia, we assessed the pulmonary capillary filtration coefficient (Kfc) through the use of in vitro-isolated, perfused rat lung preparation. We also measured the lung wet-to-dry weight ratio (W/D) and protein concentration in broncho-alveolar lavage fluid (PCBAL). Lung inflammation and oxidative stress were evaluated by use of tissue tumor necrosis factor (TNF)-α and malondialdehyde levels and lavage differential macrophage and neutrophil cell count.. Hepatic I/R injury markedly increased Kfc, W/D, PCBAL, tissue TNF-α level, and differential neutrophil cell count (P < .05). MK-571 treatment reduced neutrophil infiltration and lung inflammation and improved pulmonary capillary filtration, collectively suggesting lung protection.. Treatment with MK-571 before and during hepatic ischemia and reperfusion protects lung against pulmonary capillary barrier function impairment through decreasing pulmonary lung inflammation and lavage neutrophils.

Topics: Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Leukotriene Antagonists; Liver Diseases; Male; Multidrug Resistance-Associated Proteins; Neutrophil Infiltration; Oxidative Stress; Propionates; Quinolines; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Warm Ischemia

Reperfusion of the rat kidney has been shown to up-regulate cysteinyl leukotriene-1 receptor, an asthma-associated gene in human bronchioles, and increase expression of leukotriene D4. In this study, we aimed to investigate the efficacy of MK-571, a leukotriene D4 inhibitor, against hypersensitivity induced by kidney ischemia and reperfusion (I/R)-associated acute kidney injury.. Sprague-Dawley male rats were divided into 3 study groups: a sham-operated group, a kidney I/R group, and a group treated with MK-571 before the kidney I/R injury: MK-571 (5 mg/kg) was administered intraperitoneally 15 minutes before ischemia and every 12 hours after reperfusion up to 24 hours. Ischemia was conducted by bilateral occlusion of renal pedicles for 45 minutes, followed by releasing the clamps and closing the abdominal incision. Respiratory function was tested 24 hours after reperfusion, with the use of a 2-chamber whole body plethysmograph for conscious rats. Blood samples, pulmonary bronchoalveolar lavage fluid, and lung tissues were collected at the end of study. In 10 rats, urine was collected at baseline and the end of study.. Compared with the sham group, kidney I/R injury markedly increased enhanced pause (Penh) index during methacholine challenge test (P < .05), suggesting airway hypersensitivity; it also increased in inflammatory response and levels of hydroxyl radical production and lipid peroxidation in the lungs. In contrast, in MK-571-treated rats, Penh was muted during methacholine challenge test (P < .05).. Kidney I/R injury induces airway hypersensitivity to methacholine challenge test and inflammatory response and oxidative stress in the lungs. Treatment with MK-571, a leukotriene D4 inhibitor, effectively attenuates airway hypersensitivity, pulmonary inflammatory response, and lung and kidney injury.

Topics: Acute Kidney Injury; Animals; Anti-Inflammatory Agents; Antioxidants; Biomarkers; Bronchial Hyperreactivity; Bronchoconstriction; Bronchodilator Agents; Disease Models, Animal; Drug Administration Schedule; Hydroxyl Radical; Inflammation Mediators; Injections, Intraperitoneal; Kidney; Leukotriene Antagonists; Lipid Peroxidation; Lung; Male; Oxidative Stress; Propionates; Quinolines; Rats, Sprague-Dawley; Reperfusion Injury; Time Factors

Insufficient oxygen delivery to organs leads to tissue dysfunction and cell death. Reperfusion, although vital to organ survival, initiates an inflammatory response that may both aggravate local tissue injury and elicit remote organ damage. Polymorphonuclear neutrophil (PMN) trafficking to remote organs following ischaemia/reperfusion (I/R) is associated with the release of lipid mediators, including leucotriene (LT) B4 , cysteinyl-LTs (CysLTs) and platelet-activating factor (PAF). Yet, their potentially cooperative role in regulating I/R-mediated inflammation has not been thoroughly assessed. The present study aimed to determine the cooperative role of lipid mediators in regulating PMN migration, tissue oedema and injury using selective receptor antagonists in selected models of I/R and dermal inflammation. Our results show that rabbits, pre-treated orally with BIIL 284 and/or WEB 2086 and MK-0571, were protected from remote tissue injury following I/R or dermal inflammation in an additive or synergistic manner when the animals were pre-treated with two drugs concomitantly. The functional selectivity of the antagonists towards their respective agonists was assessed in vitro, showing that neither BIIL 284 nor WEB 2086 prevented the inflammatory response to IL-8, C5a and zymosan-activated plasma stimulation. However, these agonists elicited LTB4 biosynthesis in isolated rabbit PMNs. Similarly, a cardioprotective effect of PAF and LTB4 receptor antagonists was shown following myocardial I/R in mice. Taken together, these results underscore the intricate involvement of LTB4 and PAF in each other's responses and provide further evidence that targeting both LTs and PAF receptors provides a much stronger anti-inflammatory effect, regulating PMN migration and oedema formation.

Topics: Amidines; Animals; Azepines; Biological Assay; Carbamates; Dermis; Disease Models, Animal; Extravasation of Diagnostic and Therapeutic Materials; Extremities; Inflammation; Leukotriene B4; Leukotrienes; Male; Mice; Mice, Inbred C57BL; Myocardial Ischemia; Neutrophil Infiltration; Platelet Activating Factor; Platelet Membrane Glycoproteins; Propionates; Quinolines; Rabbits; Receptors, G-Protein-Coupled; Receptors, Leukotriene; Reperfusion Injury; Triazoles

Cysteinyl leukotriene receptor type 1 (leukotriene CysLT(1) receptor) antagonist is one of the most effective anti-inflammatory agents for asthma. The spectrum of protein targets that can be regulated by leukotriene CysLT(1) receptor antagonist in asthma is not fully understood. The present study tried to identify novel protein targets of a selective leukotriene CysLT(1) receptor antagonist MK-571 in allergic airway inflammation by analyzing the proteome of mouse bronchoalveolar lavage fluid. BALB/c mice sensitized and challenged with ovalbumin showed increased pulmonary inflammatory cell infiltration, airway mucus production and serum ovalbumin-specific IgE level. MK-571 inhibited all these allergic airway inflammation endpoints. Lavage fluid proteins were resolved by two-dimensional gel electrophoresis and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The level of fourteen bronchoalveolar lavage fluid protein spots was markedly altered by MK-571. A family of chitinases (Ym1, Ym2 and acidic mammalian chitinase), lungkine, surfactant protein-D and gamma-actin have been found for the first time to be down-regulated by leukotriene CysLT(1) receptor antagonist in mouse allergic airways. Some of the down-regulatory effects were confirmed with reverse transcription-polymerase chain reaction analyses. Taken together, we have identified novel protein targets that can be regulated by leukotriene CysLT(1) receptor antagonist in mouse allergic airway inflammation, and our findings reveal additional pharmacological actions of leukotriene CysLT(1) receptor antagonist in the treatment of asthma.

Topics: Animals; Anti-Inflammatory Agents; Asthma; Base Sequence; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Electrophoresis, Gel, Two-Dimensional; Leukotriene Antagonists; Membrane Proteins; Mice; Mice, Inbred BALB C; Microscopy; Propionates; Proteome; Quinolines; Receptors, Leukotriene; Respiratory Hypersensitivity; Reverse Transcriptase Polymerase Chain Reaction

The 5-lipoxygenase (5-LO)-derived leukotrienes (LTs) influence both local innate immunity and vascular responses, but the relative importance of effects on these two processes in sepsis is unknown. In a cecal ligation and puncture model of peritonitis with severe sepsis, 5-LO(-/-) mice showed a reduction in peritoneal neutrophil accumulation and an increase in the number of bacteria in the peritoneal cavity. Despite this impairment of local innate immunity, the null mice exhibited a marked improvement in survival, and this protection was also seen in wild-type animals treated with the LT synthesis inhibitor MK 886. A survival advantage in severe sepsis was also observed in mice treated with the cysteinyl-LT receptor antagonist MK 571, but not with the LTB(4) receptor antagonist CP 105, 696. Protection in the 5-LO(-/-) mice was associated with reduced vascular leak and serum lactate levels. Moreover, wild-type mice treated with MK 571 exhibited less sepsis-induced hypotension. These data demonstrate opposing effects of cysteinyl-LTs on innate immune vs hemodynamic responses, demonstrating protective effects on local immunity and deleterious effects on the vasculature. They also suggest the possible therapeutic utility of targeting vascular events in sepsis with cysteinyl-LT blockade.

Topics: Acidosis, Lactic; Animals; Arachidonate 5-Lipoxygenase; Capillary Permeability; Cecum; Cysteine; Disease Models, Animal; Female; Hypotension; Immunity, Innate; Leukotriene Antagonists; Leukotrienes; Ligation; Lipoxygenase Inhibitors; Male; Mice; Mice, Knockout; Peritonitis; Propionates; Punctures; Quinolines; Receptors, Leukotriene; Receptors, Leukotriene B4; Sepsis

Cysteinyl leukotrienes (CysLTs) contribute to the development of airway obstruction and inflammation in asthma; however little information is available on the role of these molecules in the pathophysiology of respiratory syncytial virus (RSV) bronchiolitis. This study was designed to evaluate the effects of RSV infection on CysLTs production in a well-established mouse infection model. Furthermore, we assessed the effect of anti-inflammatory agents (a leukotriene receptor antagonist, MK-571, and dexamethasone) on the functional and immune changes induced by RSV infection. Six to 8-wk-old BALB/c mice were infected with human RSV (strain A2). Measurements of airway function were performed using whole body plethysmography. Lung inflammation was assessed by cell counts, measurement of cytokines and CysLTs in bronchoalveolar lavage fluid (BALF) in the absence and presence of treatment with MK-571 or dexamethasone. RSV infection produced a marked increase in CysLTs in the BALF and lung tissue, recruitment of neutrophils and lymphocytes into the airways, increased IFN-gamma levels and airway hyperresponsiveness (AHR). Treatment with MK-571 decreased RSV-induced AHR without affecting the cellular and inflammatory responses to RSV. Dexamethasone decreased AHR and markedly reduced the recruitment of inflammatory cells and production of IFN-gamma. Our findings suggest CysLTs play an important role in the pathogenesis of RSV-induced airway dysfunction. Treatment with MK-571 decreases RSV-induced AHR but does not appear to alter the lung inflammatory responses to RSV. In contrast, dexamethasone decreases RSV-induced AHR but interferes with recruitment of inflammatory cells, resulting in decreased Th1 cytokines (a potentially Th2-prone environment) in this model. These studies support recent reports on the beneficial effects of CysLT receptor antagonist in human trials and provide a model for investigating the role of CysLTs in RSV bronchiolitis.

Topics: Animals; Anti-Inflammatory Agents; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Cysteine; Dexamethasone; Disease Models, Animal; Female; Inflammation; Interferon-gamma; Leukotrienes; Lymphocyte Count; Lymphocytes; Macrophages; Membrane Proteins; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Propionates; Quinolines; Receptors, Leukotriene; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human

Cysteinyl leukotrienes are potent inflammatory molecules playing a major role in asthma. The involvement of these mediators in hypersensitivity in mice is not well known. This study aimed at elucidating their implication by using MK-571, a cysLT(1)receptor antagonist. Mice were sensitized with a suspension of ovalbumin (8 microg) adsorbed to alum (2 mg) and were challenged with an aerosolized ovalbumin solution (0.5%). Inflammatory cell infiltration in the bronchoalveolar lavage (mostly eosinophils) following antigen challenge was inhibited by dexamethasone (0.1, 1 and 5 mg kg(-1)s.c.) and MK-571 (1, 10, 100 mg kg(-1)i.v.) in a dose-dependent manner. Maximal inhibition was 95% with 5 mg kg(-1)dexamethasone and 90% with 100 mg kg(-1)MK-571. When injected together they showed an additive inhibitory effect on eosinophil infiltration. Bronchial hyperreactivity, measured by the increased pulmonary insufflation pressure to carbachol injections, was also inhibited dose-dependently by MK-571. The EC(50)values for carbachol were of 22.39+/-1.12 microg kg(-1)in sensitized and challenged animals that did not receive MK-571 and increased to 43.65+/-1.10, 50.12+/-1.15 and 83.18+/-1.16 microg kg(-1)in animals treated with 1, 10 and 100 mg kg(-1)MK-571 respectively. Lung microvascular leakage (as measured by Evans blue extravasation) induced by antigen bronchoprovocation was reduced by 22% after treatment with 10 mg kg(-1)MK-571. All these inhibitory effects of MK-571 suggest a role for leukotriene D(4)in this animal model of allergic asthma.

Topics: Animals; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Capillary Permeability; Dexamethasone; Disease Models, Animal; Drug Therapy, Combination; Leukotriene Antagonists; Leukotriene D4; Male; Membrane Proteins; Mice; Mice, Inbred BALB C; Ovalbumin; Propionates; Pulmonary Eosinophilia; Quinolines; Receptors, Leukotriene

We have previously shown that mast cell stabilization attenuates peritoneal adhesion formation in the rat. The present study investigated the mechanism of this protection. Adhesions were created in weanling rats using cecal scraping and application of 95% ethanol. Rats received specific blockers for the mast cell products histamine, serotonin (5HT), leukotriene D4, and platelet activating factor intraperitoneally 30 min before laparotomy and at the time of abdominal closure. Control animals received saline. Adhesions were assessed blindly 1 week later using a standardized scale. Adhesion formation was not affected by histamine blockade using combined mepyramine and ranitidine, 5-HT1 blockade using methysergide, 5-HT3 blockade using ondansetron, leukotriene D4 blockade using MK-571, or platelet activating factor blockade using WEB-2086. However, blockade of the 5-HT2 receptor using ketanserin resulted in significant dose-dependent attenuation of adhesions compared to saline. These data suggest that mast cells mediate peritoneal adhesion formation in the rat through release of serotonin acting on 5HT2 receptors. Further understanding of this process may lead to new strategies for the prevention of postoperative adhesions.

Topics: Animals; Azepines; Disease Models, Animal; Histamine Antagonists; Leukotriene D4; Male; Mast Cells; Methysergide; Ondansetron; Peritoneal Diseases; Platelet Activating Factor; Propionates; Pyrilamine; Quinolines; Ranitidine; Rats; Rats, Sprague-Dawley; Serotonin Antagonists; Tissue Adhesions; Triazoles

The ovalbumin (OA)-sensitized Brown Norway rat (BN) demonstrates early-response (ER) and late-response (LR) allergic bronchoconstriction. To determine whether these responses could be replicated in vitro, we studied lung explants from 8-wk-old male BN rats (wt: 239 +/- 28 g), of which 19 were sensitized to OA (test) and 16 served as controls. Two weeks after sensitization, the animals' lungs were removed, filled with a 1% (wt/vol) agarose-containing solution at 37 degrees C, and cooled to 4 degrees C. Transverse slices (0.5 to 1.0 mm thick) were cut and cultured overnight. Airways were visualized with an inverted microscope and baseline images were obtained with a video camera. To study the ER, 40 airways from 15 test rats and 29 airways from 10 control rats were challenged with 2 micrograms OA and imaged each minute for 10 min. To study the LR, 40 airways from 12 test rats and 44 airways from 12 control rats were challenged with 2 micrograms OA and imaged each hour for 8 h. The maximal response (MR) for each airway was defined as the percent of airway closure. The ER and LR were both defined as an MR > or = mean + 2 SD of the controls. An ER occurred in 38 of 40 test and 2 of 29 control airways (mean MR: 42 +/- 24% versus 4 +/- 3%, p < 0.001), and was completely blocked by methysergide pretreatment in 13 airways.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Airway Resistance; Animals; Asthma; Bronchial Provocation Tests; Bronchodilator Agents; Constriction, Pathologic; Disease Models, Animal; Drug Hypersensitivity; Hypersensitivity, Delayed; Hypersensitivity, Immediate; Immunoglobulin E; In Vitro Techniques; Leukotriene D4; Male; Methysergide; Ovalbumin; Premedication; Propionates; Quinolines; Rats; Serotonin; Time Factors