leukotriene-b4 and Disease-Models--Animal

Intracerebral hemorrhage (ICH) results from blood vessels rupture in the brain, forming a blood clot in the brain parenchyma. Leakage of blood constituents causes detrimental tissue damages, ensuing long-lasting neurological deficits; however, effective therapeutic approaches are not yet developed to date. In this study, leukotriene B

Topics: Administration, Oral; Animals; Brain; Cell Movement; Cerebral Hemorrhage; Disease Models, Animal; Drug Discovery; HL-60 Cells; Humans; Leukotriene B4; Mice; Microglia; Molecular Targeted Therapy; Neutrophil Infiltration; Phenylpropionates; Receptors, Leukotriene B4; Thrombin

Remarkable effects of anti-IL-17A and anti-IL-23 antibodies on psoriasis indicate deep involvement of IL-23/Th17 axis in the pathogenesis of psoriasis. According to the current immune theory, activation of dendritic cells initiates the generation of this axis. However, this theory is not enough to explain the mechanism, because the process of this activation is obscure and the antigen that is recognized by antigen-presenting cells and pathogenic T cells has long been unidentified. Therefore, I thought of another theory as follows. Neutrophils are attracted by LTB4 at subcorneal portion and infiltrate into the epidermis. At the time of neutrophil migration through the basement membrane, basal keratinocytes in G0/G1 phase enter the cell cycle and begin to proliferate, according to the principle, "detachment-mediated cell proliferation." This passing is continuously repeated and leads to elongation of rete ridges. The IL-23/Th17 axis is generated by interactions between infiltrated neutrophils and keratinocytes. Briefly, neutrophils infiltrated into the epidermis secrete IL-17A, which acts on keratinocytes to express CCL20, a ligand for the chemokine receptor CCR6. Keratinocytes perturbed by neutrophil infiltration produce HSP70, followed by production of IL-23 via TLR4 using HSP70 as an endogenous ligand for TLR4. Natural Th17 cells expressing CCR6 are recruited to psoriatic epidermis and expand there in the presence of IL-23 and IL-1β. In this manner, the framework of the IL-23/Th17 axis is created, which acts to maintain or exacerbate psoriasis. Noteworthy is the fact that this axis causes positive feedback loop, starting from IL-17A production by neutrophils and ending in IL-17A production by nTh17 cells. Therapeutic mechanisms of anti-IL-17A and anti-IL-23 antibodies, targeting neutrophils, were also described.

Topics: Animals; Antibodies, Monoclonal; Cell Communication; Cell Movement; Cell Proliferation; Chemokine CCL20; Disease Models, Animal; Epidermis; HSP70 Heat-Shock Proteins; Humans; Interleukin-17; Interleukin-23; Keratinocytes; Leukotriene B4; Neutrophils; Psoriasis; Receptors, CCR6; Th17 Cells; Toll-Like Receptor 4

Inflammatory arthritis, including rheumatoid arthritis (RA), is characterized by infiltration of inflammatory cells into the joints. Biological agents targeting TNF-α and IL-6 dramatically improve RA. However, some RA patients do not respond to current treatments and these broadly active upstream biological agents increase the risk of severe infection. Therefore, there remains a need for other effective and safe treatments for RA. Many studies have implicated that blockade of leukotriene B4 (LTB

Topics: Animals; Arthritis; Arthritis, Rheumatoid; Clinical Trials as Topic; Disease Models, Animal; Humans; Inflammation; Leukotriene B4; Molecular Targeted Therapy; Receptors, Leukotriene B4

Itch is a sensation that provokes a desire to scratch. Mast-cell histamine was thought to be a key itch mediator. However, histamine and mast-cell degranulation were reported not to elicit scratching in animals. It was difficult to investigate the pathophysiology of itching and to evaluate the antipruritic efficacy of chemical agents in the early 1990 s. We showed that hind-paw scratching and biting were elicited by stimulation with pruritogenic agents in mice. Those results demonstrated for the first time that cutaneous itching could be evaluated behaviorally in animals. We established various animal models of pathological itch of the skin (dry skin, mosquito allergy, surfactant-induced pruritus, and herpes zoster) and mucus membranes (pollen allergy). Mast-cell histamine did not play a key role in itching in any animal model examined except for the pollen allergy model. Histamine is not an exclusive itch mediator of mast cells; tryptase and leukotriene B4 released from mast cells also act as itch mediators. Epidermal keratinocytes release several itch mediators, such as leukotriene B4, sphingosylphosphorylcholine, thromboxane A2, nociceptin, nitric oxide, and histamine, which may play important roles in pathological itching. Appropriate animal models of pathological itching are needed for pharmacological evaluation of the antipruritic efficacy of chemical agents.

Topics: Animals; Antipruritics; Disease Models, Animal; Drug Evaluation, Preclinical; Histamine; Humans; Hypersensitivity; Leukotriene B4; Mast Cells; Mucous Membrane; Pruritus; Skin; Tryptases

The purpose of this review is to summarize the role that murine models of arthritis are playing in the understanding of human rheumatoid arthritis and how leukotriene B(4) (LTB(4)) is emerging as an important target in this field. Both the collagen-induced arthritis (CIA) model and the K/BxN serum transfer arthritis model have contributed to outline the potential mechanisms involved in inflammatory arthritis. Indeed, the CIA model has contributed to the development of effective anti-TNFalpha and anti-IL-1beta based treatments for RA that are currently in the clinic. Many recent studies in mouse models have suggested a critical role for LTB(4) and its receptors in the development of inflammatory arthritis. Inhibitors of LTB(4) biosynthesis as well as LTB(4) receptors are protective in mouse models of RA and mice deficient in the LTB(4) biosynthetic enzymes or LTB(4) receptors are resistant to disease development suggesting several promising targets for RA in this pathway.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cytokines; Disease Models, Animal; Leukotriene B4; Receptors, Leukotriene B4

The contribution of CD8+ T cells to the development of airway hyperresponsiveness and airway inflammation has received increased attention recently. CD8+ T cells, which are capable of secreting TH2 cytokines, including IL-4, IL-5, and IL-13, have been described in asthmatic subjects and in animals sensitized and challenged with allergen. A subset of these IL-13-producing CD8+ T cells, effector memory CD8+ T cells in the mouse, express a high-affinity receptor for leukotriene B4 (BLT1), and expression of this receptor is essential for their accumulation in the lung and development of airway hyperresponsiveness and airway inflammation. A similar subset of CD8+/BLT1+/IL-13+ T cells has also been identified in the bronchoalveolar lavage fluid of asthmatic subjects, suggesting a pathogenic role for this unique subset of CD8+ T cells in asthma.

Topics: Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; CD8-Positive T-Lymphocytes; Cytokines; Disease Models, Animal; Disease Progression; Humans; Leukotriene B4; Mice

Itch, a skin sensation that provokes a desire to scratch, is a common complaint. Severe itch accompanying various skin diseases such as atopic dermatitis is an important issue related to the quality of life. Although histamine from mast cells has been thought to play an essential role in itch, many severe pruritic diseases respond poorly to the H(1) histamine receptor antagonists. Therefore the precise mechanisms and mediators of itch in most pruritic diseases are unclear. To investigate the detailed mechanisms of the induction of itch, we have developed a mouse model. Studies using this model have demonstrated that keratinocytes play an important role in the induction of itch. The identification of keratinocyte stimulus factors and of products in keratinocytes could lead to developing new antipruritic medicines.

Topics: Animals; Disease Models, Animal; Drug Design; Epidermal Cells; Histamine Release; Humans; Keratinocytes; Leukotriene B4; Mast Cells; Mice; Nitric Oxide; Pruritus; Receptor, PAR-2; Substance P

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

Ischaemia induces an acute inflammatory response in myocardial tissue with an early phase of neutrophil accumulation, which is accelerated by reperfusion. In experimental models, interventions that deplete neutrophils or inhibit their function cause a significant reduction in myocardial infarct size. These cells, therefore, may exacerbate tissue injury through the release of free radicals and proteolytic enzymes. Neutrophil recruitment depends on the presence of inflammatory mediators. Leukotriene B4, interleukin 8 and the complement fragment C5a have been implicated in this process. Studies using antibodies to the selectin, integrin and immunoglobulin superfamily adhesion molecules indicate that they also have a crucial role in myocardial neutrophil recruitment.

Topics: Animals; Antibodies; Cell Adhesion Molecules; Complement C5a; Disease Models, Animal; Free Radicals; Humans; Interleukin-8; Leukotriene B4; Myocardial Reperfusion Injury; Myocardial Stunning; Neutrophils; Platelet Activating Factor

Topics: Animals; Coronary Disease; Coronary Vessels; Disease Models, Animal; Enzyme Inhibitors; Humans; Leukotriene B4; Lipoxygenase; Lipoxygenase Inhibitors; Muscle, Smooth, Vascular; Quercetin; Rats; SRS-A

The sheep model of allergic airway disease shares many pathophysiological similarities with allergic airway disease in humans. Studies performed in this animal model present strong evidence that the release of arachidonic acid metabolites plays an important role in the development of late bronchial responses to antigen challenge. The release of leukotrienes through the lipoxygenase pathway during the acute bronchial obstruction after inhalation of Ascaris suum antigen represents the key factor for the initiation of the subsequent events, namely the late phase response and the bronchial hyperreactivity. If this hypothesis can be substantiated in patients with bronchial asthma then pharmacologic modification of the lipoxygenase pathway and/or products may be important in the treatment of asthma.

Topics: Animals; Arachidonic Acids; Ascaris; Bronchial Provocation Tests; Bronchial Spasm; Disease Models, Animal; Hypersensitivity, Delayed; Leukotriene B4; Sheep; SRS-A

Evidence has been presented that lipoxygenase products of arachidonic acid metabolism released during the early stages of allergic reactions play an important role in the subsequent development of late bronchial responses. Moreover, because of this, the activity of the lipoxygenase pathway and sensitivity to the products generated may be important factors that distinguish between dual and acute responders. We recognize that these studies were performed in an experimental animal model of allergic airway disease. If the same mechanisms that are active in sheep are proven active in humans, then pharmacologic modification of the lipoxygenase pathway or its products (or both) may be important for the treatment of some forms of asthma.

Topics: Allergens; Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Arachidonic Acids; Asthma; Bronchial Spasm; Disease Models, Animal; Hypersensitivity, Delayed; Hypersensitivity, Immediate; Leukotriene B4; Models, Biological; Platelet Activating Factor; Prostaglandin-Endoperoxide Synthases; Sheep; SRS-A

Recent studies have suggested that heparin is effective for treatment of inflammatory bowel disease (IBD) and its various effects (in addition to the anticoagulant effect). We evaluated the effects of argatroban as an antithrombin drug on trinitrobenzene sulfonic acid (TNB)-induced colitis, an established model of IBD.. Rats were randomly assigned to four groups in which mini-osmotic pumps containing saline (TNB-S), argatroban (TNB-A), or 100 U/kg heparin (TNB-H) were intraperitoneally implanted. Three days after the pumps were implanted, TNB was infused via the anus, and colitis was induced. After 5 days, prothrombin time (PT), activated partial prothrombin time (APTT), antithrombin III (AT-III), platelet, fibrinogen, colonic wet weight, macroscopic damage score, histological score, mucosal myeloperoxidase activity and mucosal leukotrien B4 (LTB4) levels were compared among the four groups.. The APTT was prolonged in the heparin treatment group but only slightly prolonged in the argatroban treatment group. The platelet count and the fibrinogen level were higher in the TNB-S group than in the healthy control group and the AT-III level was slightly lower in the TNB-S group than in the healthy control group and lower still in the TNB-H group.. The colonic wet weight was similar among the four groups while the macroscopic damage score, histological score, mucosal myeloperoxidase activity and the mucosal LTB4 level were significantly decreased in the TNB-A and TNB-H groups. Argatroban, as well as heparin may be effective for treatment of TNB-induced colitis.

Topics: Analysis of Variance; Animals; Antithrombins; Arginine; Blood Coagulation Tests; Colitis; Disease Models, Animal; Heparin; Immunoenzyme Techniques; Infusion Pumps, Implantable; Leukotriene B4; Male; Nitrobenzenes; Peroxidase; Pipecolic Acids; Rats; Rats, Wistar; Sulfonamides; Sulfonic Acids

The anti-inflammatory effect of n-3 PUFA on the gingivae has already been demonstrated in animal models. The aim of this double-blind, randomized pilot study versus placebo is to evaluate this action in human experimentally-induced gingivitis. For 14 days (D0-D14), 37 healthy volunteers practised intensive oral hygiene, then abstained from brushing their teeth for 21 days (D14 to D35). On D28, the patients were randomized into 2 groups: 18 received the drug (fish oil: 30% n-3 PUFA) and 19 received the placebo (olive oil containing only 1% of n-3 PUFA) at a daily dosage of 6 g (i.e., 1.8 g of n-3 PUFA) 3x for 8 days (D28-D35). The plaque (PI), gingival (GI) and papillary bleeding (PBI) indices were measured on D14, D28 and D35. On D28 and D35, 10 volunteers underwent removal of an inter-dental vestibular papilla, between the 1st and the 2nd superior premolars, to measure out arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA). A gingival biopsy was also taken in another 11 patients, to assay prostaglandin E2 (PGE2) and leukotriene B4 (LTB4). The clinical results of the trial demonstrated, in particular, a significant reduction of GI in the treated group (p < 0.05, Student t-test), but no significant difference between the groups. The biochemical results showed that EPA, DHA and DPA were found in the cells sampled, at higher levels in the subjects taking the drug, with a significant difference for EPA between the 2 groups (p < 0.05, Student t-test). The levels of AA, PGE2 and LTB4 are reduced in the experimental group and increased in the control group, with no significant difference. The LTB4 levels decreased but this difference just failed to reach significance (p = 0.09. Student t-test). This human experimental gingivitis study demonstrated that n-3 PUFA induced a tendency towards reduced inflammation but it was not possible to conclude significant efficacy.

Topics: Adolescent; Adult; Anti-Inflammatory Agents; Arachidonic Acids; Dental Plaque Index; Dinoprostone; Disease Models, Animal; Docosahexaenoic Acids; Double-Blind Method; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Fatty Acids, Unsaturated; Female; Fish Oils; Gingiva; Gingival Hemorrhage; Gingivitis; Humans; Leukotriene B4; Male; Olive Oil; Periodontal Index; Pilot Projects; Placebos; Plant Oils

To compare the analgesic and anti-inflammatory effects of the nonsteroidal anti-inflammatory drugs (NSAID), ketoprofen (2.20 and 3.63 mg/kg of body weight) and phenylbutazone (4.40 mg/kg), in an acute equine synovitis model.. 4 groups of 6 horses received NSAID or saline solution in a randomized design.. 24 clinically normal mares and geldings.. Left intercarpal joints were injected with sterile carrageenan to induce synovitis at the same time as IV administration of NSAID or saline solution. Clinical assessments were made and synovial fluid was withdrawn at 0, 1, 3, 6, 9, 12, 24, and 48 hours.. The eicosanoids, prostaglandin E2 (PGE2) and leukotriene B4, increased in synovial fluid after synovitis induction in all horses then returned to near baseline by 48 hours. All NSAID-treated horses had decreased PGE2, compared with saline-treated horses. This effect lasted longer in phenylbutazone-treated horses than in ketoprofen-treated horses. There were no treatment effects on leukotriene B4. In saline-treated animals, lameness, joint temperature, and synovial fluid volume, protein concentration, and nucleated cells increased 3 to 12 hours after induction, with marked reduction by 48 hours. Only phenylbutazone treatment reduced lameness, joint temperature, and synovial fluid volume.. Phenylbutazone was more effective than ketoprofen in reducing lameness, joint temperature, synovial fluid volume, and synovial fluid PGE2. Results do not support lipoxygenase inhibition by either NSAID.. This reversible model induced synovial fluid alterations similar to those observed in horses with septic arthritis. Results indicate that phenylbutazone may be more useful than ketoprofen in treating acute joint inflammation.

Topics: Acute Disease; Animals; Anti-Inflammatory Agents, Non-Steroidal; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Horse Diseases; Horses; Joints; Ketoprofen; Lameness, Animal; Leukotriene B4; Male; Phenylbutazone; Proteins; Synovial Fluid; Synovitis

Ganoderma, a fungal genus, is a traditional medicine with immuno-modulating effects. Asthma is an inflammatory disease of airways, and the main trigger of asthma is allergic inflammation. In this study, the effects of Ganoderma (an anti-inflammatory agent) given via oral administration (G/O) or intraperitoneal injection (G/IP) on asthma was evaluated. Forty BALB/c mice were divided into four groups, including the control, OVA-challenge, OVA-challenge + G/O, and OVA-challenge + G/IP. To determine AHR, the MCh challenge test was done. The levels of IL-1β, -4, -5, -6, -8, -10, -12, -13, -17, -25, -33, -38, Cys-LT, LTB4, and hydroxyproline were measured. Finally, lung histopathology was evaluated to determine eosinophilic inflammation, goblet cell hyperplasia, and mucus hyper-secretion. Treatment with G/O and G/IP could significantly reduce the levels of IL-1β, -5, -6, -8, -17, -25, -33, and -38; the levels of IL-4 and IL-13 had no significant changes, but the levels of IL-10 and IL-12 were enhanced. The mice treated with G/O and G/IP showed decreased levels of Cys-LT, LTB4, peribronchial and perivascular inflammation, but no significant changes were observed in AHR, hydroxyproline level, goblet cell hyperplasia, and mucus hyper-secretion. Ganoderma can be applied as an immunomodulatory and anti-inflammatory agent for managing asthma.

Topics: Animals; Anti-Inflammatory Agents; Asthma; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Ganoderma; Hydroxyproline; Hyperplasia; Inflammation; Leukotriene B4; Lung; Mice; Mice, Inbred BALB C; Ovalbumin

Acute lung injury is one of major complications associated with sepsis, responsible for morbidity and mortality. Patients who suffer from acute lung injury often require respiratory support under sedations, and it would be important to know the role of sedatives in lung injury. We examined volatile anesthetic isoflurane, which is commonly used in surgical setting, but also used as an alternative sedative in intensive care settings in European countries and Canada. We found that isoflurane exposure attenuated neutrophil recruitment to the lungs in mice suffering from experimental polymicrobial abdominal sepsis. We found that isoflurane attenuated one of major neutrophil chemoattractants LTB

Topics: Acute Lung Injury; Anesthetics, Inhalation; Animals; Chemotaxis; Disease Models, Animal; Eicosanoids; Isoflurane; Leukotriene B4; Lung; Male; Mice, Inbred C57BL; Neutrophil Infiltration; Receptors, Leukotriene B4; Sepsis

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

Pathogens of otitis media (OM) induce inflammatory responses in the middle ear (ME), characterized by mucosal hyperplasia, leukocyte infiltration, and inflammatory mediators, including arachidonic acid metabolites. We studied the role of the eicosanoid leukotriene B4 (LTB4) in OM.. Expression of LTB4-related genes was evaluated by gene array and single-cell RNA-Seq in MEs infected with nontypeable. ME expression of LTB4-related genes was observed by gene arrays and scRNA-Seq. However, not all genes involved in LTB4 generation occurred in any one specific cell type. Moreover, LTB4 receptor inhibition significantly reduced mucosal hyperplasia and virtually eliminated leukocyte infiltration.. ME expression of LTB4-related genes suggest a functional role in OM disease. The fact that LTB4-generation is spread across different cell types is consistent with a transcellular pathway of eicosanoid biosynthesis involving cell-to-cell signaling as well as transfer of biosynthetic intermediates between cells. The dramatic reduction in ME leukocyte infiltration caused by U75302 indicates that LTB4 plays a major role in ME inflammatory cell recruitment, acting

Topics: Animals; Disease Models, Animal; Haemophilus influenzae; Leukocytes; Leukotriene B4; Otitis Media

Bullous pemphigoid-like epidermolysis bullosa acquisita (EBA) is an autoantibody-driven, granulocyte-mediated skin disease. The role of cellular metabolism and its potential as a therapeutic target in EBA are unknown. We investigated the effect of 2-deoxy-D-glucose and metformin in the antibody transfer model of EBA. Both metformin and 2-deoxy-D-glucose attenuated disease in this model. Subsequently, we demonstrate that the stimulation of neutrophils by immune complexes increases the rate of aerobic glycolysis and that this increase is required to induce the release of leukotriene B4 and ROS critical for EBA. Accordingly, 2-deoxy-D-glucose as an inhibitor of the glycolytic enzymes hexokinase and phosphoglucose isomerase and heptelidic acid, an inhibitor of glyceraldehyde-3-phosphate dehydrogenase, blunted this neutrophil response. Decreasing oxidative phosphorylation, metformin also inhibited this neutrophil response but only when applied in suprapharmacological doses, rendering a direct effect of metformin on neutrophils in vivo unlikely. Considering that the oxidative phosphorylation inhibitor oligomycin likewise inhibits these neutrophil responses and that immune complex stimulation does not alter the rate of oxidative phosphorylation, these results, however, suggest that intact mitochondria are necessary for neutrophil responses. Collectively, we highlight 2-deoxy-D-glucose and metformin as potential drugs and both glycolysis and oxidative phosphorylation in neutrophils as promising therapeutic targets in EBA.

Topics: Animals; Autoantibodies; Deoxyglucose; Disease Models, Animal; Epidermolysis Bullosa Acquisita; Glucose; Glycolysis; Humans; Leukotriene B4; Metformin; Mice; Mitochondria; Neutrophils; Oxidative Phosphorylation; Reactive Oxygen Species; Skin

The mechanisms of lymphedema development are not well understood, but emerging evidence highlights the crucial role the immune system plays in driving its progression. It is well known that lymphatic function deteriorates as lymphedema progresses; however, the connection between this progressive loss of function and the immune-driven changes that characterize the disease has not been well established. In this study, we assess changes in leukocyte populations in lymph nodes within the lymphatic drainage basin of the tissue injury site (draining lymph nodes, dLNs) using a mouse tail model of lymphedema in which a pair of draining collecting vessels are left intact. We additionally quantify lymphatic pump function using established near infrared (NIR) lymphatic imaging methods and lymph-draining nanoparticles (NPs) synthesized and employed by our team for lymphatic tissue drug delivery applications to measure lymphatic transport to and resulting NP accumulation within dLNs associated with swelling following surgery. When applied to assess the effects of the anti-inflammatory drug bestatin, which has been previously shown to be a possible treatment for lymphedema, we find lymph-draining NP accumulation within dLNs and lymphatic function to increase as lymphedema progresses, but no significant effect on leukocyte populations in dLNs or tail swelling. These results suggest that ameliorating this loss of lymphatic function is not sufficient to reverse swelling in this surgically induced disease model that better recapitulates the extent of lymphatic injury seen in human lymphedema. It also suggests that loss of lymphatic function during lymphedema may be driven by immune-mediated mechanisms coordinated in dLNs. Our work indicates that addressing both lymphatic vessel dysfunction and immune cell expansion within dLNs may be required to prevent or reverse lymphedema when partial lymphatic function is sustained.

Topics: Animals; Disease Models, Animal; Female; Kinetics; Leucine; Leukocytes; Leukotriene B4; Lymph Nodes; Lymphatic Vessels; Lymphedema; Male; Mice; Mice, Inbred C57BL; Protease Inhibitors

Epidermolysis bullosa acquisita and mucous membrane pemphigoid are autoimmune blistering diseases characterized by mucocutaneous blisters elicited by an autoantibody-mediated immune response against specific proteins of the epidermal basement membrane. The antibiotic dapsone is frequently used to treat both diseases, but its therapeutic effectiveness is uncertain, and its mode of action in these diseases is largely unknown. We evaluated the effect of dapsone in antibody transfer mouse models of epidermolysis bullosa acquisita and mucous membrane pemphigoid, which do not allow the drawing of conclusions on clinical treatment regimens but can be instrumental to partially uncover the mode(s) of action of dapsone in these diseases. Dapsone significantly mitigated inflammation in both models, reducing the recruitment of neutrophils into the skin and disrupting their release of leukotriene B

Topics: Animals; Cell Adhesion Molecules; Dapsone; Disease Models, Animal; Dose-Response Relationship, Drug; Kalinin; Leukotriene B4; Macrophages; Mice; Mice, Inbred C57BL; Neutrophils; Pemphigoid, Bullous; RAW 264.7 Cells; Reactive Oxygen Species

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

Leukotriene B

Topics: Aged; Animals; Arachidonate 5-Lipoxygenase; Cerebral Cortex; Disease Models, Animal; Female; Humans; Infarction, Middle Cerebral Artery; Leukotriene A4; Leukotriene B4; Male; Middle Aged; Rats, Wistar; Severity of Illness Index; Stroke

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 co-administration of 3α-hydroxymasticadienoic acid (3α-OH MDA) and diligustilide (DLG) generates a synergist gastroprotective effect on indomethacin-induced gastric damage. However, the related protective activities of the compounds alone (or in combination) remain unclear. In the present study, we evaluated the anti-inflammatory and antioxidative activities, as well as the potential modulation of important gasotransmitters of each compound individually and in combination using the indomethacin-induced gastric damage model. Male Wistar rats were treated orally with the 3α-OH MDA, DLG, or their combination (at a fixed ratio of 1:1, 1:3, and 3:1) 30 min before the generation of gastric mucosal lesions with indomethacin (30 mg/kg, p.o.). Three hours later, the gastric injury (mm

Topics: Animals; Anti-Inflammatory Agents; Anti-Ulcer Agents; Antioxidants; Dinoprostone; Disease Models, Animal; Drug Therapy, Combination; Gastric Mucosa; Hydrogen Sulfide; Indomethacin; Leukotriene B4; Male; Nitric Oxide; Rats, Wistar; Stomach Ulcer; Superoxide Dismutase; Triterpenes; Tumor Necrosis Factor-alpha

Leukotriene B

Topics: Animals; Disease Models, Animal; Inflammation; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Receptors, Leukotriene B4; Signal Transduction

Oxazolidinone hydroxamic acid derivatives were synthesised and evaluated for inhibitory activity against leukotriene (LT) biosynthesis in three

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Cell Line; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Humans; Hydroxamic Acids; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred BALB C; Molecular Structure; Oxazolidinones; Structure-Activity Relationship; Zymosan

Moderate aerobic exercise training accelerates the resolution of lung fibrosis in a model of bleomycin-induced pulmonary fibrosis. However, whether it can inhibit the development of lung fibrosis is unknown.. C57Bl/6 mice were distributed into four groups: Control (Co), Exercise (Exe), Bleomycin (Bleo), and Bleomycin+Exercise (Bleo+Exe). A single bleomycin dose (1.5 UI/kg) was administered orotracheally and treadmill exercise started in the same day, enduring for 4 weeks, 5x/week, 60 minutes/session, at moderate intensity. Lung mechanics, systemic and pulmonary inflammation, and lung remodeling were evaluated. Lung homogenates were used to evaluate the antioxidant status.. Total cells, macrophages, lymphocytes, and neutrophils numbers, in agreement with IL-6 levels, were higher in the BAL and serum of Bleo group, compared to other groups. In addition, lung levels of LTB4 in Bleo were higher than other groups, whereas SOD activity and nitric oxide levels in exercised groups (Exe and Exe+Bleo) compared to the Bleo group. Lung GPX activity was lower in Bleo and Exe+Bleo groups compared to others. Exe and Exe+Bleo groups also showed higher IL-10 expression by lung macrophages than other groups, whereas TGF-. Aerobic exercise training initiated concomitantly with induction of pulmonary fibrosis reduces lung and systemic inflammation but fails to inhibit lung fibrosis and mechanics impairment.

Topics: Animals; Bleomycin; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Interleukin-10; Interleukin-6; Leukotriene B4; Lung; Lymphocytes; Macrophages; Male; Mice; Mice, Inbred C57BL; Neutrophils; Nitric Oxide; Physical Conditioning, Animal; Pulmonary Fibrosis; Receptors, CCR7; Superoxide Dismutase; Vascular Endothelial Growth Factor A

To investigate the possible role of Naringenin in AMPK signaling pathway in LPS-induced septic cardiac dysfunction in mice and to elucidate the inherent mechanism.. Male C57 mice were used in the establishment of mouse sepsis model. The effect of Naringenin on septic cardiac dysfunction was observed. Echocardiographic parameters were recorded. Western blot was employed to detect the expressions of BCL-2, BAX, cleaved caspase-3, pNF-kB and IkB-α. Myocardial mitochondria were isolated and extracted. Real-time PCR was applied to detect the expressions of Cox4i, Cox5a mRNA, mt-Nd1, mt-Nd2, mt-Co1 and mt-Co2 mRNA. Western blot was employed to detect the expressions of Complex I, Complex II, and OPA1 to evaluate the effects of Naringenin on myocardial mitochondrial biology and function in septic cardiac dysfunction.. The expressions of TNF-α, IL-6, pNF-κB and IκB-α have changed after Naringenin treatment. IκB-α expression was decreased, expressions of TNF-α, IL-6 and pNF-κB were increased. Naringenin has significantly inhibited AMPK and ACC phosphorylation, and decreased PGC1α expression. Moreover, Naringenin reversed the increased expressions of PGC1α and phosphorylation of AMPK and ACC by U75302 treatment, and decreased the expressions of complex I, complex II and OPA1.. Naringenin inhibits LTB4/BLT1 receptors to attenuate cardiomyocyte inflammation and apoptosis, which may mediate the protective effect of anti-septic cardiac dysfunction by activating AMPK signaling pathway and inhibiting NF-κB signaling and mitochondrial damage.

Topics: Adenylate Kinase; Animals; Apoptosis; Disease Models, Animal; Flavanones; Heart Diseases; Inflammation; Interleukin-6; Leukotriene B4; Lipopolysaccharides; Male; Mice; Myocardium; Myocytes, Cardiac; NF-kappa B; NF-KappaB Inhibitor alpha; Receptors, Leukotriene B4; Sepsis; Signal Transduction; Tumor Necrosis Factor-alpha

The treatment of most autoimmune diseases still relies on systemic immunosuppression and is associated with severe side effects. The development of drugs that more specifically abrogate pathogenic pathways is therefore most desirable. In nature, such specificity is exemplified, e.g., by the soft tick-derived biotherapeutic Coversin, which locally suppresses immune responses by inhibiting complement factor 5 (C5) and leukotriene B4 (LTB4). C5a, a proteolytic fragment of C5, and LTB4 are critical drivers of skin inflammation in pemphigoid diseases (PDs), a group of autoimmune blistering skin diseases. Here, we demonstrate that both Coversin and its mutated form L-Coversin, which inhibits LTB4 only, dose dependently attenuate disease in a model of bullous pemphigoid-like epidermolysis bullosa acquisita (BP-like EBA). Coversin, however, reduces disease more effectively than L-Coversin, indicating that inhibition of C5 and LTB4 synergize in their suppressing effects in this model. Further supporting the therapeutic potential of Coversin in humans, we found that C5a and LTB4 are both present in the blister fluid of patients with BP in quantities inducing the recruitment of granulocytes and that the number of cells expressing their receptors, C5aR1 and BLT1, respectively, is increased in perilesional skin. Collectively, our results highlight Coversin and possibly L-Coversin as potential therapeutics for PDs.

Topics: Animals; Biological Products; Cells, Cultured; Chemotaxis; Collagen Type VII; Complement C5; Complement Inactivating Agents; Disease Models, Animal; Granulocytes; Healthy Volunteers; Humans; Leukotriene B4; Male; Mice; Neutrophils; Pemphigoid, Bullous; Primary Cell Culture; Rabbits; Skin

Rheumatoid arthritis is characterized by progressive joint inflammation and affects ~1% of the human population. We noted single-nucleotide polymorphisms (SNPs) in the apoptotic cell-engulfment genes ELMO1, DOCK2, and RAC1 linked to rheumatoid arthritis. As ELMO1 promotes cytoskeletal reorganization during engulfment, we hypothesized that ELMO1 loss would worsen inflammatory arthritis. Surprisingly, Elmo1-deficient mice showed reduced joint inflammation in acute and chronic arthritis models. Genetic and cell-biology studies revealed that ELMO1 associates with receptors linked to neutrophil function in arthritis and regulates activation and early neutrophil recruitment to the joints, without general inhibition of inflammatory responses. Further, neutrophils from the peripheral blood of human donors that carry the SNP in ELMO1 associated with arthritis display increased migratory capacity, whereas ELMO1 knockdown reduces human neutrophil migration to chemokines linked to arthritis. These data identify 'noncanonical' roles for ELMO1 as an important cytoplasmic regulator of specific neutrophil receptors and promoter of arthritis.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Arthritis, Experimental; Arthritis, Rheumatoid; Chemotaxis; Collagen; Complement C5a; Cytoplasm; Disease Models, Animal; Female; Gene Expression Profiling; Healthy Volunteers; Humans; Intravital Microscopy; Joints; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Polymorphism, Single Nucleotide; Proteomics; Severity of Illness Index; Signal Transduction; Time-Lapse Imaging

Coconut oil is used as a dietary oil worldwide, and its healthy effects are recognized by the fact that coconut oil is easy to digest, helps in weight management, increases healthy cholesterol, and provides instant energy. Although topical application of coconut oil is known to reduce skin infection and inflammation, whether dietary coconut oil has any role in decreasing skin inflammation is unknown. In this study, we showed the impact of dietary coconut oil in allergic skin inflammation by using a mouse model of contact hypersensitivity (CHS). Mice maintained on coconut oil showed amelioration of skin inflammation and increased levels of cis-5, 8, 11-eicosatrienoic acid (mead acid) in serum. Intraperitoneal injection of mead acid inhibited CHS and reduced the number of neutrophils infiltrating to the skin. Detailed mechanistic studies unveiled that mead acid inhibited the directional migration of neutrophils by inhibiting the filamentous actin polymerization and leukotriene B

Topics: 8,11,14-Eicosatrienoic Acid; Actins; Animals; Biomarkers; Capillary Permeability; Chemotaxis; Coconut Oil; Dermatitis, Atopic; Dermatitis, Contact; Dietary Fats, Unsaturated; Disease Models, Animal; Female; Immunohistochemistry; Immunophenotyping; Leukotriene B4; Lipid Metabolism; Mice; Neutrophils; Skin

The anti-inflammatory profile of DPA was investigated via a dextran sulphate sodium (DSS)-induced colitis model, and was also compared with those of EPA and DHA. The results showed that DPA could significantly reduce (stronger than EPA and DHA) the disease activity index score, macroscopic appearance score, colon shortening, histological assessment, and myeloperoxidase accumulation in the colon. In addition, DPA also inhibited the abnormal production and mRNA expression of pro-inflammatory cytokines, namely tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 and improved the production and expression of an anti-inflammatory cytokine, IL-10. Furthermore, the molecular mechanisms underlying these effects were also explored through the synthesis pathway of eicosanoids. DPA could inhibit the synthesis of leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) more greatly while differences of cyclooxygenase (COX) and 5-lipoxidase (LOX) contents in these three groups were not significant. We ascribed these effects to the easier incorporation of DPA into inflammatory cells leading to the decrease in the substrate for the synthesis of pro-inflammatory eicosanoids (PGE2 and LTB4). Besides, DPA-derived mediators might also be involved.

Topics: Animals; Anti-Inflammatory Agents; Body Weight; Colitis, Ulcerative; Colon; Cytokines; Dextran Sulfate; Dinoprostone; Disease Models, Animal; Fatty Acids, Unsaturated; Inflammation; Interleukin-1beta; Leukotriene B4; Lipoxygenase; Male; Mice; Plant Extracts; Prostaglandin-Endoperoxide Synthases; RNA, Messenger; Tumor Necrosis Factor-alpha

5-Lipoxygenase (5-LO) plays a vital role in the host innate immune response, including bacteria-induced inflammation. Apical periodontitis (AP) is due to immune disorders caused by imbalances between bacterial invasion and subsequent host defense response. In this work, we investigated the role of 5-lipoxygenase in AP by using 5- lo knockout mice (5- lo-/- mice). Results showed that 5- lo-/- mice had greater periapical bone loss and more osteoclasts positive for tartrate-resistant acid phosphatase staining than did wild-type mice, as determined by micro-computed tomography and histologic staining. The inflammation- and osteoclastogenesis-related factors IL-1β, TNF-α, RANK, and RANKL were also significantly elevated in 5- lo-/- mice, whereas osteoprotegerin was reduced. Furthermore, peritoneal macrophages from 5- lo-/- mice revealed an obviously impaired ability to phagocytose the AP pathogenic bacteria Fusobacterium nucleatum. In vivo experiments confirmed that 5- lo knockout led to decreased macrophage recruitment and increased F. nucleatum infection around the periapical area due to decreased leukotriene B

Topics: Animals; Arachidonate 5-Lipoxygenase; Blotting, Western; Cytokines; Disease Models, Animal; Fluorescent Antibody Technique; Fusobacterium nucleatum; Immunity, Innate; Leukotriene B4; Male; Mice; Mice, Knockout; Osteoclasts; Periapical Periodontitis; Phagocytosis; Real-Time Polymerase Chain Reaction; Tartrate-Resistant Acid Phosphatase; X-Ray Microtomography

Leukotriene B4 (LTB4) is a highly potent neutrophil chemoattractant and neutrophils induces inflammatory response and oxidative stress when they recruit to and infiltrate in the injuried/inflamed site, such as the brain parenchyma after aneurysmal subarachnoid hemorrhage (SAH). This study is to investigate the potential effects of inhibition of LTB4 synthesis on neutrophil recruitment, inflammatory response and oxidative stress, as well as early brain injury (EBI) in rats after SAH. A pre-chiasmatic cistern SAH model of rats was used in this experiment. SC 57461A was used to inhibit LTB4 synthesis via intracerebroventricular injection. The brain tissues of temporal lobe after SAH were analyzed. Neuronal injury, brain edema and neurological function were evaluated to investigate the development of EBI. We found that inhibition of LTB4 synthesis after SAH could reduce the level of myeloperoxidase, alleviate the inflammatory response and oxidative stress, and reduce neuronal death in the brain parenchyma, and ameliorate brain edema and neurological behavior impairment at 24h after SAH. These results suggest that inhibition of LTB4 synthesis might alleviate EBI after SAH possibly via reducing the neutrophil-generated inflammatory response and oxidative stress.

Topics: Animals; beta-Alanine; Blood-Brain Barrier; Brain Edema; Brain Injuries; Disease Models, Animal; Inflammation; Leukotriene B4; Male; Neutrophils; Oxidative Stress; Rats, Sprague-Dawley; Subarachnoid Hemorrhage

Topics: Animals; Bone Morphogenetic Protein 2; Cell Line; Cell Proliferation; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Endothelial Cells; Endothelium, Vascular; Humans; Hypertension, Pulmonary; Leukotriene B4; Piperidines; Pulmonary Artery; Rats; Signal Transduction; Stem Cells

Leukotriene B4 (LTB4) is a potent chemoattractant and inflammatory mediator involved in multiple inflammatory diseases. Substance P (SP) has been reported to promote production of LTB4 in itch-associated response in vivo and in some immune cells in vitro. Here, we investigated the role of LTB4 in acute pancreatitis (AP), AP-associated acute lung injury (ALI) and the related mechanisms of LTB4 production in AP. In vivo, murine AP model was induced by caerulein and lipopolysaccharide or L-arginine. The levels of LTB4 and its specific receptor BLT1 were markedly upregulated in both AP models. Blockade of BLT1 by LY293111 attenuated the severity of AP, decreased neutrophil reverse transendothelial cell migration (rTEM) into the circulation and alleviated the severity of ALI. In vitro, treatment of pancreatic acinar cells with SP increased LTB4 production. Furthermore, SP treatment increased phosphorylation of protein kinase C (PKC) α and mitogen activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), p-38 MAPK and c-Jun NH2-terminal kinase (JNK). Finally, blockade of neurokinin-1 receptor by CP96345 significantly attenuated the severity of AP and decreased the level of LTB4 when compared to AP group. In summary, these results show that SP regulates the production of LTB4 via PKCα/MAPK pathway, which further promotes AP-associated ALI through neutrophil rTEM.

Topics: Acinar Cells; Acute Lung Injury; Animals; Benzoates; Cells, Cultured; Ceruletide; Disease Models, Animal; Humans; Leukotriene B4; Male; MAP Kinase Signaling System; Mice; Mice, Inbred BALB C; Neutrophils; Pancreatitis, Acute Necrotizing; Protein Kinase C; Receptors, Leukotriene B4; Receptors, Neurokinin-1; Substance P; Transendothelial and Transepithelial Migration

Leukotriene B4 (LTB4) synthesis is enhanced in the colonic mucosa in patients with inflammatory bowel disease (IBD). BLT1, a high-affinity receptor for LTB4, exhibits no effect on the progression of dextran sodium sulfate (DSS)-induced colitis, which mostly relies on innate immunity. Here, we reported that BLT1 regulates trinitrobenzene sulfonic acid (TNBS)-induced colitis, which reflects CD4

Topics: Animals; Cell Differentiation; Cells, Cultured; Colitis; Colon; Cytokines; Dendritic Cells; Disease Models, Animal; Humans; Inflammation Mediators; Inflammatory Bowel Diseases; Leukotriene B4; Mice; Mice, Inbred C57BL; Mice, Knockout; Receptors, Leukotriene B4; Signal Transduction; Th1 Cells; Th17 Cells; Trinitrobenzenesulfonic Acid

Inflammatory bowel diseases (IBD) occurred in genetically predisposed people exposed to environmental triggers. Diet has long been suspected to contribute to the development of IBD. Supplementation with n-3 polyunsaturated fatty acids (PUFA) protects against intestinal inflammation in rodent models while clinical trials showed no benefits. We hypothesized that intervention timing is crucial and dietary fatty acid pattern may influence intestinal environment to modify inflammation genesis. The aim of this study was to evaluate the dietary effect of PUFA composition on intestinal inflammation.. Animals received diet varying in their PUFA composition for four weeks before TNBS-induced colitis. Colon inflammatory markers and gut barrier function parameters were assessed. Inflammatory pathway PCR arrays were determined.. n-3 diet significantly decreased colon iNOS, COX-2 expression, IL-6 production, and LTB4 production but tended to decrease colon TNF. Dietary n-3 PUFA influence colitis development by attenuating inflammatory markers. Further research is required to better define dietary advice with a scientific rationale.

Topics: Animals; Claudin-1; Colitis; Cyclooxygenase 2; Disease Models, Animal; Fatty Acids, Omega-3; Inflammatory Bowel Diseases; Interleukin-6; Leukotriene B4; Male; Nitric Oxide Synthase Type II; Occludin; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha

Both leukotrienes and neutrophils have been linked to plaque destabilization. Despite being evoked, the role of leukotriene B4 (LTB4) in neutrophil recruitment to plaques and the concomitant effects of these two actors on plaque stability remain to be proven. Since both actors are elicited during endotoxaemia, a condition associated with the risk of cardiovascular events, we investigated whether endotoxaemia promotes LTB4-mediated neutrophil infiltration in plaques and explored the roles of LTB4 and neutrophils in plaque destabilization.. Endotoxaemia induced by repeated peritoneal endotoxin injections at a non-lethal dose (1.5 mg/kg, 5 days) in chow-fed aged Apoe-/- mice (over 45 weeks old) resulted in neutrophil infiltration and activation in plaques. Subsequently to neutrophil invasion, plaques exhibited increased features of vulnerability: reduced collagen content, expanded necrotic cores, and thinned fibrous caps. These plaque features were reproduced by direct deposition of isolated neutrophils onto murine atheromatous carotid arteries in an in vivo assay. In endotoxemic mice, plaques produced increased amounts of LTB4. Genomic or pharmacological impairments of this production reduced neutrophil infiltration, collagenolysis, and apoptosis of smooth muscle cells in plaques of endotoxemic mice. Furthermore, conditioned media of human culprit plaques (CPs) contained more LTB4 than non-CPs and levels of LTB4 correlated to both neutrophil activation markers and endotoxin releases in CPs.. These results show that the increased neutrophil recruitment elicited by LTB4 contributes to increase features of plaque destabilization in endotoxemic contexts and point out LTB4 as a potential therapeutic target in atherosclerosis.

Topics: Animals; Aorta; Aortic Diseases; Arachidonate 5-Lipoxygenase; Atherosclerosis; Disease Models, Animal; Endotoxemia; Female; Fibrosis; Humans; Leukotriene B4; Lipopolysaccharides; Male; Mice, Inbred C57BL; Mice, Knockout, ApoE; Necrosis; Neutrophil Activation; Neutrophil Infiltration; Neutrophils; Paracrine Communication; Plaque, Atherosclerotic; Signal Transduction; Tissue Culture Techniques

The potential of omega-3 poly-unsaturated fatty acids (PUFAs) as a therapeutic target for psoriasis, a chronic inflammatory skin disease of IL-23/IL-17 axis, is a long-disputed question, since various epidemiological studies have suggested the association between high-intake of omega-3 PUFAs and the reduced frequency and severity of psoriasis. However, their actual significance and the molecular mechanisms remain largely unknown. To address these issues, we focused on resolvin E1 (RvE1), an omega-3 PUFAs-derived metabolite, and examined its effects on psoriatic dermatitis, using an imiquimod-induced mouse psoriasis model. RvE1 potently suppressed the inflammatory cell infiltration and epidermal hyperplasia in the psoriatic skin. RvE1 decreased the mRNA expression of IL-23 in the skin. Consistently, RvE1 inhibited IL-23 production by dendritic cells (DCs) in vitro. Furthermore, RvE1 exerted inhibitory effects on migration of cutaneous DCs and γδ T cells, a major IL-17-producing cell population in mouse, both in vivo and in vitro. These suppressive effects of RvE1 were mediated by its antagonistic function on BLT1, a receptor of leukotriene B4, and were also observed in human DCs, Th17 and Tc17 cells. Our results indicate a novel mechanism of omega-3 PUFA-mediated amelioration of psoriasis, and suggest a potential of RvE1 as a therapeutic target for psoriasis.

Topics: Animals; Cell Movement; Dendritic Cells; Dermatitis; Disease Models, Animal; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Female; Humans; Inflammation; Interleukin-17; Leukotriene B4; Mice; Mice, Inbred C57BL; Psoriasis; RNA, Messenger; Skin; Th17 Cells

Age-related macular degeneration (AMD), a progressive chronic disease of the central retina, is associated with aging and is a leading cause of blindness worldwide. Here, we demonstrate that leukotriene B4 (LTB4) receptor 1 (BLT1) promotes laser-induced choroidal neovascularization (CNV) in a mouse model for wet-type AMD. CNV was significantly less in BLT1-deficient (BLT1-KO) mice compared with BLT1-WT controls. Expression of several proangiogenic and profibrotic factors was lower in BLT1-KO eyes than in BLT1-WT eyes. LTB4 production in the eyes was substantially increased in the early phase after laser injury. BLT1 was highly expressed in M2 macrophages in vitro and in vivo, and ocular BLT1+ M2 macrophages were increased in the aged eyes after laser injury. Furthermore, M2 macrophages were rapidly attracted by LTB4 and subsequently produced VEGF-A- through BLT1-mediated signaling. Consequently, intravitreal injection of M2 macrophages augmented CNV formation, which was attenuated by BLT1 deficiency. Thus, laser-induced injury to the retina triggered LTB4 production and attracted M2 macrophages via BLT1, leading to development of CNV. A selective BLT1 antagonist (CP105696) and 3 LTB4 inhibitors (zileuton, MK-886, and bestatin) reduced CNV in a dose-dependent manner. CP105696 also inhibited the accumulation of BLT1+ M2 macrophages in the laser-injured eyes of aged mice. Together, these results indicate that the LTB4-BLT1 axis is a potentially novel therapeutic target for CNV of wet-type AMD.

Topics: Animals; Benzopyrans; Carboxylic Acids; Choroidal Neovascularization; Disease Models, Animal; Eye; Eye Injuries; Hydroxyurea; Indoles; Lasers; Leucine; Leukotriene B4; Macrophages; Macular Degeneration; Male; Mice; Mice, Knockout; Neovascularization, Pathologic; Receptors, Leukotriene B4; Signal Transduction

Epilepsy therapy is based on drugs that treat the symptoms rather than the underlying mechanisms of the disease (epileptogenesis). There are no treatments for preventing seizures or improving disease prognosis, including neurological comorbidities. The search of pathogenic mechanisms of epileptogenesis highlighted that neuroinflammatory cytokines [i.e. interleukin-1β (IL-1β), tumour necrosis factor-α (Tnf-α)] are induced in human and experimental epilepsies, and contribute to seizure generation in animal models. A major role in controlling the inflammatory response is played by specialized pro-resolving lipid mediators acting on specific G-protein coupled receptors. Of note, the role that these pathways have in epileptogenic tissue remains largely unexplored. Using a murine model of epilepsy, we show that specialized pro-resolving mechanisms are activated by status epilepticus before the onset of spontaneous seizures, but with a marked delay as compared to the neuroinflammatory response. This was assessed by measuring the time course of mRNA levels of 5-lipoxygenase (Alox5) and 15-lipoxygenase (Alox15), the key biosynthetic enzymes of pro-resolving lipid mediators, versus Il1b and Tnfa transcripts and proteins. In the same hippocampal tissue, we found a similar delayed expression of two main pro-resolving receptors, the lipoxin A4 receptor/formyl peptide receptor 2 and the chemerin receptor. These receptors were also induced in the human hippocampus after status epilepticus and in patients with temporal lobe epilepsy. This evidence supports the hypothesis that the neuroinflammatory response is sustained by a failure to engage pro-resolving mechanisms during epileptogenesis. Lipidomic LC-MS/MS analysis showed that lipid mediator levels apt to resolve the neuroinflammatory response were also significantly altered in the hippocampus during epileptogenesis with a shift in the biosynthesis of several pro-resolving mediator families including the n-3 docosapentaenoic acid (DPA)-derived protectin D1. Of note, intracerebroventricular injection of this mediator during epileptogenesis in mice dose-dependently reduced the hippocampal expression of both Il1b and Tnfa mRNAs. This effect was associated with marked improvement in mouse weight recovery and rescue of cognitive deficit in the novel object recognition test. Notably, the frequency of spontaneous seizures was drastically reduced by 2-fold on average and the average seizure duration was shortened by 40% after

Topics: Animals; Anticonvulsants; Arachidonate 15-Lipoxygenase; Arachidonate 5-Lipoxygenase; CD11b Antigen; Cytokines; Dinoprostone; Disease Models, Animal; Docosahexaenoic Acids; Encephalitis; Epilepsy; Gene Expression Regulation; Hippocampus; Kainic Acid; Leukotriene B4; Lipid Metabolism; Lipoxins; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic

A recent study suggests that interleukin-31 (IL-31) exerts its effect via indirect mechanisms rather than through direct stimulation of cutaneous nerves. However, the underlying peripheral mechanisms of IL-31-induced itch in the skin remain unclear. Therefore, the present study investigated the peripheral mechanisms underlying IL-31-induced itch in mice. IL-31-induced itch-related response was inhibited by anti-allergic drugs (tranilast and azelastine), but not by an H1 histamine receptor antagonist (terfenadine). Furthermore, a 5-lipoxygenase inhibitor (zileuton), but not a cyclooxygenase inhibitor (indomethacin), and a leuko-triene B4 (LTB4) receptor antagonist (CMHVA) attenuated the action of IL-31. IL-31 receptor-immunoreactivity was observed in the epidermis and primary sensory neurones. IL-31 receptor mRNA was expressed in mouse keratinocytes and dorsal root ganglia neurones. IL-31 increased the production of LTB4 in mouse keratinocytes. These results suggest that IL-31 elicits itch not only through direct action on primary sensory neurones, but also by inducing LTB4 production in keratinocytes.

Topics: Animals; Anti-Allergic Agents; Behavior, Animal; Cells, Cultured; Disease Models, Animal; Interleukins; Keratinocytes; Leukotriene Antagonists; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice, Inbred ICR; Oncostatin M Receptor beta Subunit; Pruritus; Receptors, Interleukin; Receptors, Leukotriene B4; Sensory Receptor Cells; Signal Transduction; Skin

Recognizing patients at risk for pulmonary complications (PC) is of high clinical relevance. Migration of polymorphonuclear leukocytes (PMN) to inflammatory sites plays an important role in PC, and is tightly regulated by specific chemokines including interleukin (IL)-8 and other mediators such as leukotriene (LT)B4. Previously, we have reported that LTB4 indicated early patients at risk for PC after trauma. Here, the relevance of LTB4 to indicating lung integrity in a newly established long-term porcine severe trauma model (polytrauma, PT) was explored.. Twelve pigs (3 months old, 30 ± 5kg) underwent PT including standardized femur fracture, lung contusion, liver laceration, hemorrhagic shock, subsequent resuscitation and surgical fracture fixation. Six animals served as controls (sham). After 72h lung damage and inflammatory changes were assessed. LTB4 was determined in plasma before the experiment, immediately after trauma, and after 2, 4, 24 or 72h. Bronchoalveolar lavage (BAL)-fluid was collected prior and after the experiment.. Lung injury, local gene expression of IL-8, IL-1β, IL-10, IL-18 and PMN-infiltration into lungs increased significantly in PT compared with sham. Systemic LTB4 increased markedly in both groups 4h after trauma. Compared with declined plasma LTB4 levels in sham, LTB4 increased further in PT after 72h. Similar increase was observed in BAL-fluid after PT.. In a severe trauma model, sustained changes in terms of lung injury and inflammation are determined at day 3 post-trauma. Specifically, increased LTB4 in this porcine long-term model indicated a rapid inflammatory alteration both locally and systemically. The results support the concept of LTB4 as a biomarker for PC after severe trauma and lung contusion.

Topics: Animals; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Humans; Inflammation; Interleukins; Leukotriene B4; Lung; Lung Injury; Neutrophils; Swine; Wounds and Injuries

Topics: Acetates; Animals; Anti-Inflammatory Agents; Chemokine CCL2; Cyclopropanes; Disease Models, Animal; Dose-Response Relationship, Drug; E-Selectin; Estradiol; Gene Expression Regulation; Inflammation Mediators; Interleukin-6; Leukotriene Antagonists; Leukotriene B4; Male; NF-kappa B; Nitric Oxide Synthase Type II; Orchiectomy; Prostate; Prostatitis; Quinolines; Rats, Wistar; Receptors, Leukotriene; Sulfides; Time Factors; Tumor Necrosis Factor-alpha

Unresolved experimental Lyme arthritis in C3H 5-lipoxygenase (5-LOX)

Topics: Animals; Arachidonate 5-Lipoxygenase; Borrelia burgdorferi; Disease Models, Animal; Humans; Leukotriene B4; Lyme Disease; Macrophages; Mice; Mice, Transgenic; Phagocytosis; Receptors, Leukotriene B4; Tetrazoles

Topics: Animals; Arachidonate 5-Lipoxygenase; Chromatography, Liquid; Disease Models, Animal; Eosinophils; Epidermolysis Bullosa Acquisita; Female; Inflammation; Leukotriene B4; Male; Mass Spectrometry; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Neutrophil Infiltration; Neutrophils; Pemphigoid, Bullous; Receptors, Leukotriene B4; Skin

Hypercapnia is common in mechanically ventilated patients. Experimentally, 'therapeutic hypercapnia' can protect, but it can also cause harm, depending on the mechanism of injury. Hypercapnia suppresses multiple signalling pathways. Previous investigations have examined mechanisms that were known a priori, but only a limited number of pathways, each suppressed by CO. Because of the complexity and interdependence of processes in acute lung injury, this study sought to fill in knowledge gaps using an unbiased screen, aiming to identify a specifically upregulated pathway.. Using genome-wide gene expression analysis in a mouse model of ventilator-induced lung injury, we discovered a previously unsuspected mechanism by which CO. Inspired CO

Topics: alpha-Tocopherol; Animals; Carrier Proteins; Disease Models, Animal; Gene Deletion; Gene Expression Profiling; Gene Expression Regulation; Genome-Wide Association Study; Hypercapnia; Leukotriene B4; Lung; Male; Mice, Inbred C57BL; Oxidative Stress; RNA, Messenger; Signal Transduction; Up-Regulation; Ventilator-Induced Lung Injury

Alzheimer's disease (AD) is associated with amyloid plaques (Aβ) and hyperphosphorylated tau protein tangles in the brain. We investigated the possible neuroprotective role of flavocoxid, a dual inhibitor of cyclooxygenases-1/2 (COX-1/2) and 5-Lipoxygenase (5-LOX), in triple-transgenic (3xTg-AD) mice.. Mice were 3 months at the beginning of the study.. Animals received once daily for 3-month saline solution or flavocoxid (20 mg/kg/ip).. Morris water maze was used to assess learning and memory. Histology was performed to evidence Aβ plaques and neuronal loss, while inflammatory proteins were determined by western blot analysis.. Saline-treated 3xTg-AD mice showed an impairment in spatial learning and memory (assessed at 6 months of age), and increased expression of inflammatory and apoptotic molecules. Treatment of 3xTg-AD mice with flavocoxid reduced: (1) learning and memory loss; (2) the increased eicosanoid production and the phosphorylation level of amyloid precursor protein (APP-pThr668), Aβ 1-42, p-tau (pThr181), pERK, and the activation of the NLRP3 inflammasome; (3) Aβ plaques; and (4) neuronal loss, compared to saline-treated animals.. Pharmacological blockade of both COX-1/2 and 5-LOX was able to counteract the progression of AD by targeting pathophysiological mechanisms up- and downstream of Aβ and tau.

Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Brain; Catechin; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Drug Combinations; Interleukin-1beta; Leukotriene B4; Lipoxygenase Inhibitors; Male; Maze Learning; Memory; Mice, Transgenic; Neuroprotective Agents; NLR Family, Pyrin Domain-Containing 3 Protein; tau Proteins

Airway inflammation in chronic obstructive pulmonary disease (COPD) is refractory to corticosteroids and hence COPD treatment is hindered and insufficient. This study assessed the effects of oral treatment with Montelukast (10 and 30 mg/kg) or dexamethasone (20 mg/kg) for 20 days on COPD model induced by chronic exposure to lipopolysaccharide (LPS). Six groups of male guinea pigs were studied. Group 1: naïve group, group 2: exposed to saline nebulization. Groups 3, 4, 5, and 6: exposed to 9 nebulizations of LPS (30 μg/ml) for 1 hour, 48 hours apart with or without treatment with Montelukast or dexamethasone. Airway hyperreactivity (AHR) to methacholine (MCh), histopathological study and bronchoalveolar lavage fluid (BALF) as well as lung tissue analyses were performed 48 hours after the final exposure to LPS (day 20). LPS-induced pulmonary dysfunction was associated with increased neutrophil count, leukotriene (LT) B4, and tumor necrosis factor (TNF)-α in BALF. Moreover, there was an increase in malondialdehyde (MDA) level and a decrease in histone deacetylases(HDAC) activity in the lung tissue. Both Montelukast (10 or 30 mg /kg) and dexamethasone significantly reduced neutrophil count in BALF and inflammatory cells in lung parenchyma as well as TNF-α, and MDA levels. However, dexamethasone was more effective (p < 0.05). Montelukast, at a dose of 30 mg /kg, significantly reduced specific airway resistance after the 9th LPS exposure, attenuated AHR to MCh, decreased LTB4 and increased HDAC activity in comparison to dexamethasone. These results suggest that treatment with Montelukast can be useful in chronic airway inflammatory diseases including COPD poorly responsive to glucocorticoids.

Topics: Acetates; Animals; Bronchoalveolar Lavage Fluid; Chronic Disease; Cyclopropanes; Dexamethasone; Disease Models, Animal; Glucocorticoids; Guinea Pigs; Histone Deacetylases; Inflammation; Leukocyte Count; Leukotriene Antagonists; Leukotriene B4; Lipopolysaccharides; Lung; Male; Malondialdehyde; Neutrophils; Pulmonary Disease, Chronic Obstructive; Quinolines; Respiratory Hypersensitivity; Sulfides; Tumor Necrosis Factor-alpha

Anaphylactic shock is associated with severe hypotension. Potassium channel blockers, such as 4-aminopyridine, induce vasoconstriction. The objective of this study was to test the ability of 4-aminopyridine to restore blood pressure and increase survival in anaphylactic shock.. Experimental study.. Physiology laboratory.. Adult male Wistar rats.. Rats were sensitized with ovalbumin (1 mg SC), and anaphylactic shock was induced by IV injection of ovalbumin (1 mg). Experimental groups included non-allergic rats (NA) (n = 6); allergic rats (Controls) (n = 6); allergic rats treated with 4-aminopyridine (4-aminopyridine) (1 mg/kg) (n = 6); and allergic rats treated with epinephrine (EPI) (10 µg/kg) (n = 6). Treatments were administered 1 minute after induction of anaphylactic shock.. Mean arterial blood pressure, heart rate, and survival were measured for 60 minutes. Plasma levels of histamine, leukotriene B4, prostaglandin E2, prostaglandin F2, pH, and HCO3 were measured. Mean arterial blood pressure was normal in the NA group; severe hypotension and high mortality were observed in controls; normalization of mean arterial blood pressure, heart rate, and increased survival were observed in 4-aminopyridine and EPI groups. All allergic 4-aminopyridine-treated rats survived after the induction of anaphylactic shock. Histamine level was higher in controls and the 4-aminopyridine group but reduced in the EPI group. Prostaglandin E2 increased in controls and EPI group and decreased in 4-aminopyridine group; prostaglandin F2 increased in controls but decreased in 4-aminopyridine and EPI groups. Leukotriene B4 decreased in 4-aminopyridine and EPI groups. Metabolic acidosis was prevented in the 4-aminopyridine group.. Our data suggest that voltage-dependent K+ channel inhibition with 4-aminopyridine treatment restores blood pressure and increases survival in the Wistar rat model of anaphylactic shock. 4-aminopyridine or related voltage-dependent K channel blockers could be a useful additional therapeutic approach to treatment of refractory anaphylactic shock.

Topics: 4-Aminopyridine; Acidosis; Anaphylaxis; Animals; Blood Pressure; Dinoprost; Dinoprostone; Disease Models, Animal; Epinephrine; Heart Rate; Histamine; Leukotriene B4; Male; Potassium Channel Blockers; Rats, Wistar; Vasoconstrictor Agents

Cytosolic phospholipase A2 (cPLA2) plays a key role in the development of late-phase anaphylaxis. L-Glutamine (Gln), a nonessential amino acid, has anti-inflammatory activity via inhibiting cPLA2.. We used a penicillin-induced murine model of anaphylaxis, and late-phase anaphylaxis was quantified by measuring the increase in the hematocrit (Ht) value. Various inhibitors, small interfering RNA, and knockout mice were used in inhibition experiments. Phosphorylation and protein expression of cPLA2, ERK, and MAPK phosphatase 1 (MKP-1) were detected by Western blotting.. Leukotriene (LT) B4 was found to be another potent inducer of late-phase anaphylaxis besides the known mediator platelet-activating-factor (PAF). Gln efficiently prevented late-phase anaphylaxis when it was administered up to 3 h after challenge injection via inhibiting cPLA2. Inhibition studies indicated that p38 MAPK was the major upstream regulator of cPLA2. Gln dephosphorylated p38 and cPLA2 via up-regulating the negative regulator of p38 MAPK, i.e., MKP-1 protein. MKP-1 blockade abrogated all the effects of Gln.. Of the cPLA2 metabolites, PAF and LTB4 play a key role in the development of late-phase anaphylaxis, and Gln prevents the reaction via MKP-1-dependent deactivation of cPLA2.

Topics: Anaphylaxis; Animals; Disease Models, Animal; Dual Specificity Phosphatase 1; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Female; Glutamine; Leukotriene B4; Mice; Mice, Knockout; p38 Mitogen-Activated Protein Kinases; Phospholipases A2, Cytosolic; Phosphorylation; Platelet Activating Factor; RNA, Small Interfering

5-lipoxygenase (5-LOX), a member of the lipoxygenase gene family, is a key enzyme assisting in the conversion of arachidonic acid to 5-HETE and leukotrienes. Tumor-associated macrophages (TAMs) have a critical role in the progression and metastasis of many tumors, including ovarian tumors. Moreover, TAMs are often found in a high density in the hypoxic areas of tumors. However, the relevant mechanisms have not been studied explicitly until now. In this study, we found that the expression of 5-LOX strongly correlated with the density of TAMs in hypoxic areas of human ovarian tumor tissues. In cultured ovarian cancer cells, 5-LOX metabolites were increased under hypoxic conditons. Increased 5-LOX metabolites from hypoxic ovarian cancer cells promoted migration and invasion of macrophages, which was further demonstrated to be mediated by the upregulation of matrix metalloproteinase (MMP)-7 expression through the p38 pathway. Besides, we also showed that 5-LOX metabolites enhanced the release of tumor necrosis factor (TNF-α) and heparin-binding epidermal growth factor-like growth factor through upregulation of MMP-7. Furthermore, in animal models, Zileuton (a selective and specific 5-LOX inhibitor) reduced the MMP-7 expression and the number of macrophages infiltrating in the xenograft. Our findings suggest for the first time that increased metabolites of 5-LOX from hypoxic ovarian cancer cells promote TAM infiltration. These results of this study have immediate translational implications for the therapeutic exploitation of TAMs.

Topics: Animals; Arachidonate 5-Lipoxygenase; Cell Line; Cell Line, Tumor; Chemotaxis, Leukocyte; Disease Models, Animal; Female; Heparin-binding EGF-like Growth Factor; Heterografts; Humans; Hydroxyeicosatetraenoic Acids; Hydroxyurea; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Leukotriene B4; Macrophages; MAP Kinase Signaling System; Matrix Metalloproteinase 7; Mice; Neoplasm Metastasis; Ovarian Neoplasms; Tumor Necrosis Factor-alpha

Some studies suggest that 5-lipoxygenase (5-LOX) inhibition or leukotriene receptor antagonism may effectively attenuate different kinds of pain. In the present study, we investigated whether esculetin (which, among other actions, potently inhibits 5-LOX) possesses analgesic activity in acute non-inflammatory pain and acute inflammatory pain models in rats. We also examined the effects of zileuton, a selective 5-LOX inhibitor, on esculetin activity. Plasma concentrations of leukotriene B4 (LTB4 ) after administration of esculetin were also determined. Esculetin (1.25-20 mg/kg, i.p.) dose-dependently alleviated hyperalgesia and exhibited antinociceptive effects in both experimental models. The greatest effect of esculetin was observed with a dose of 20 mg/kg. In carrageenan-induced inflammatory pain in rats, 20 mg/kg esculetin reversed or mitigated hyperalgesia, increasing the threshold to mechanical stimuli from a control value of -23.8 ± 1.8% to 15.2 ± 2.2% (P < 0.01) and that to thermal stimuli from -52.5 ± 6.1% to -9.5 ± 3.9% (P < 0.01). In non-inflammatory pain, after esculetin (20 mg/kg) administration the threshold values to mechanical and thermal stimuli increased to 75.9 ± 4.2% and 59.2 ± 4.3%, respectively (P < 0.01 for both). Zileuton (30 mg/kg, p.o.) alone slightly but significantly increased the pain threshold in the non-inflammatory and inflammatory acute pain models. Pretreatment with 30 mg/kg, p.o., zileuton significantly enhanced the analgesic activity of 5 mg/kg, i.p., esculetin in both pain models. Moreover, esculetin (10 mg/kg, i.p.) decreased LTB4 concentrations in the blood from 244 ± 29 pg/mL in the control group to 185 ± 11 pg/mL (P < 0.005). The results of the present study suggest the involvement of the 5-LOX pathway in esculetin analgesia.

Topics: Analgesia; Analgesics; Animals; Arachidonate 5-Lipoxygenase; Disease Models, Animal; Hydroxyurea; Hyperalgesia; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pain; Pain Threshold; Rats; Umbelliferones

The controversial results from different studies suggested that leukocyte recruitment mediated by leukotriene B4 (LTB4) and its receptor might improve pathogen clearance, but might also aggravate organ injury during sepsis. The present study was performed to compare the effect of BLT1 ligand LTB4 and its antagonist U-75302 on the development of sepsis.. Sepsis in mice was induced by cecal ligation and puncture (CLP). The mice were allocated into sham group, CLP group, U-75302 group, and LTB4 group. In the latter three groups, CLP mice were treated by intraperitoneal saline, U-75302, and LTB4, respectively. Their effect on the progression of sepsis were compared by histopathologic tests, level of systemic cytokines, counts of immune cells and bacterial clearance, and survival rate.. The histopathologic tests showed that U-75302 attenuated lung injury, whereas LTB4 aggravated liver injury. LTB4 increased the plasma levels of interleukin-6, tumor necrosis factor-α, and U-75302 increased the level of plasma interleukin-10. LTB4 increased whereas U-75302 reduced the neutrophil numbers in the peritoneal lavage fluid. LTB4 also increased the number of peritoneal and splenic CD4(+) and CD8(+) T cells. Bacterial clearance in blood and peritoneal lavage fluid was significantly enhanced in the LTB4 group. Both U-75302 and LTB4 did not change the survival rate significantly compared with vehicle, but mortality in the LTB4 group was significantly higher than in the U-75302 group. Dose response analyses were also performed to compare the effect of U-75302 and LTB4 at different doses. Different doses of both agents did not influence the survival rate of CLP mice.. U-75302 attenuates sepsis-induced organ injury, whereas LTB4 increases the leukocyte recruitment toward infection site, but LTB4 showed a more lethal effect than U-75302 during polymicrobial sepsis.

Topics: Animals; Disease Models, Animal; Fatty Alcohols; Glycols; Leukotriene B4; Mice, Inbred C57BL; Random Allocation; Receptors, Leukotriene B4; Sepsis

Neutrophilic infiltration is a leading contributor to pathology in a number of pulmonary disease states, including cystic fibrosis. Hepoxilin A3 (HXA3) is a chemotactic eicosanoid shown to mediate the transepithelial passage of neutrophils in response to infection in several model systems and at multiple mucosal surfaces. Another well-known eicosanoid mediating general neutrophil chemotaxis is leukotriene B4 (LTB4). We sought to distinguish the roles of each eicosanoid in the context of infection of lung epithelial monolayers by Pseudomonas aeruginosa. Using human and mouse in vitro transwell model systems, we used a combination of biosynthetic inhibitors, receptor antagonists, as well as mutant sources of neutrophils to assess the contribution of each chemoattractant in driving neutrophil transepithelial migration. We found that following chemotaxis to epithelial-derived HXA3 signals, neutrophil-derived LTB4 is required to amplify the magnitude of neutrophil migration. LTB4 signaling is not required for migration to HXA3 signals, but LTB4 generation by migrated neutrophils plays a significant role in augmenting the initial HXA3-mediated migration. We conclude that HXA3 and LTB4 serve independent roles to collectively coordinate an effective neutrophilic transepithelial migratory response.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Bacteria; Bacterial Infections; Calcium Signaling; Cell Line; Chemotaxis, Leukocyte; Disease Models, Animal; Female; Gene Knockdown Techniques; Humans; Leukotriene B4; Mice; Neutrophil Infiltration; Neutrophils; Pseudomonas aeruginosa; Receptors, Leukotriene B4; Transendothelial and Transepithelial Migration

Arachidonic acid (ARA) is an essential fatty acid and a major constituent of biomembranes. It is converted into various lipid mediators, such as prostaglandin E2 (PGE2), which is involved in the development of rheumatoid arthritis (RA). However, the effects of dietary ARA on RA are unclear. Our objective was to clarify the effects of dietary ARA on an experimental rat arthritis model.. Lew rats were fed three contents of ARA diet (0.07%, 0.15% or 0.32% ARA in diet (w/w)), a docosahexaenoic acid (DHA) diet (0.32% DHA), or a control diet. After 4 weeks, arthritis was induced by injection of Freund's complete adjuvant into the hind footpad. We observed the development of arthritis for another 4 weeks, and evaluated arthritis severity, fatty acid and lipid mediator contents in the paw, and expression of genes related to lipid mediator formation and inflammatory cytokines. Treatment with indomethacin was also evaluated.. The ARA content of phospholipids in the paw was significantly elevated with dietary ARA in a dose-dependent manner. Dietary ARA as well as DHA did not affect arthritis severity (paw edema, arthritis score, and bone erosion). PGE2 content in the paw was increased by arthritis induction, but was not modified by dietary ARA. Dietary ARA did not affect the contents of other lipid mediators and gene expression of cyclooxygenase (COX)-1, COX-2, lipoxgenases and inflammatory cytokines. Indomethacin suppressed arthritis severity and PGE2 content in the paw.. These results suggest that dietary ARA increases ARA content in the paw, but has no effect on arthritis severity and PGE2 content of the paw in a rat arthritis model.

Topics: Animals; Arachidonic Acid; Arthritis, Experimental; Bone and Bones; Dietary Supplements; Dinoprostone; Disease Models, Animal; Gene Expression Regulation; Leukotriene B4; Lipoxins; Male; Rats, Inbred Lew; Time Factors

Phospholipase A2 (PLA2)-derived proinflammatory lipid mediators such as prostaglandin E2 (PGE2), leukotrienes B4 (LTB4), lysophosphatidylcholine (LPC), and free fatty acids (FFA) are implicated in spinal cord injury (SCI) pathologies. Reducing the levels of these injurious bioactive lipid mediators is reported to ameliorate SCI. However, the specific role of the group IVA isoform of PLA2 cytosolic PLA2 (cPLA2) in lumbar spinal canal stenosis (LSS) due to cauda equina compression (CEC) injury is not clear. In this study, we investigated the role of cPLA2 in a rat model of CEC using a non-toxic cPLA2-preferential inhibitor, arachidonyl trifluoromethyl ketone (ATK).. LSS was induced in adult female rats by CEC procedure using silicone blocks within the epidural spaces of L4 to L6 vertebrae. cPLA2 inhibitor ATK (7.5 mg/kg) was administered by oral gavage at 2 h following the CEC. cPLA2-derived injurious lipid mediators and the expression/activity of cPLA2, 5-lipoxygenase (5-LOX), and cyclooxygenase-2 (COX-2) were assessed. ATK-treated (CEC + ATK) were compared with vehicle-treated (CEC + VEH) animals in terms of myelin levels, pain threshold, and motor function.. ATK treatment of CEC animals reduced the phosphorylation of cPLA2 (pcPLA2) determined by Western blot, improved locomotor function evaluated by rotarod task, and reduced pain threshold evaluated by mechanical hyperalgesia method. Levels of FFA and LPC, along with PGE2 and LTB4, were reduced in CEC + ATK compared with CEC + VEH group. However, ATK treatment reduced neither the activity/expression of 5-LOX nor the expression of COX-2 in CEC + VEH animals. Increased cPLA2 activity in the spinal cord from CEC + VEH animals correlated well with decreased spinal cord as well as cauda equina fiber myelin levels, which were restored after ATK treatment.. The data indicate that cPLA2 activity plays a significant role in tissue injury and pain after LSS. Reducing the levels of proinflammatory and tissue damaging eicosanoids and the deleterious lipid mediator LPC shows therapeutic potential. ATK inhibits cPLA2 activity, thereby decreasing the levels of injurious lipid mediators, reducing pain, improving functional deficits, and conferring protection against LSS injury. Thus, it shows potential for preclinical evaluation in LSS.

Topics: Administration, Oral; Analysis of Variance; Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Enzyme Inhibitors; Fatty Acids; Female; Hyperalgesia; Leukotriene B4; Locomotion; Lysophosphatidylcholines; Nociception; Polyradiculopathy; Rats; Rats, Sprague-Dawley

The 5-lipoxygenase product 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE) is the most powerful human eosinophil chemoattractant among lipid mediators and could play a major pathophysiological role in eosinophilic diseases such as asthma. Its actions are mediated by the OXE receptor, orthologs of which are found in many species from humans to fish, but not rodents. The unavailability of rodent models to examine the pathophysiological roles of 5-oxo-ETE and the OXE receptor has substantially hampered progress in this area. As an alternative, we have explored the possibility that the cat could serve as an appropriate animal model to investigate the role of 5-oxo-ETE. We found that feline peripheral blood leukocytes synthesize 5-oxo-ETE and that physiologically relevant levels of 5-oxo-ETE are present in bronchoalveolar lavage fluid from cats with experimentally induced asthma. 5-Oxo-ETE (EC50, 0.7nM) is a much more potent activator of actin polymerization in feline eosinophils than various other eicosanoids, including leukotriene (LT) B4 and prostaglandin D2. 5-Oxo-ETE and LTB4 induce feline leukocyte migration to similar extents at low concentrations (1nM), but at higher concentrations the response to 5-oxo-ETE is much greater. Although high concentrations of selective human OXE receptor antagonists blocked 5-oxo-ETE-induced actin polymerization in feline granulocytes, their potencies were about 200 times lower than for human granulocytes. We conclude that feline leukocytes synthesize and respond to 5-oxo-ETE, which could potentially play an important role in feline asthma, a common condition in this species. The cat could serve as a useful animal model to investigate the pathophysiological role of 5-oxo-ETE.

Topics: Actins; Allergens; Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Asthma; Benzeneacetamides; Benzothiazoles; Bronchoalveolar Lavage Fluid; Cats; Chemotaxis; Cynodon; Disease Models, Animal; Eosinophils; Female; Gene Expression; Humans; Leukotriene B4; Male; Neutrophils; Polymerization; Primary Cell Culture; Prostaglandin D2; Receptors, Eicosanoid

To investigate the effects of Clostridium butyricum (C. butyricum) on experimental gastric ulcers (GUs) induced by alcohol, restraint cold stress, or pyloric ligation in mice, respectively.. One hundred and twenty mice were randomly allocated into three types of gastric ulcer models (n = 40 each), induced by alcohol, restraint cold stress, or pyloric ligation. In each GU model, 40 mice were allocated into four groups (n = 10 each): the sham control group; model group (GU induction without pretreatment); C. butyricum group (GU induction with C. butyricum pretreatment); and Omeprazole group (GU induction with Omeprazole pretreatment). The effects of C. butyricum were evaluated by examining the histological changes in the gastric mucosal erosion area, the activities of superoxide dismutase (SOD) and catalase (CAT), the level of malondialdehyde (MDA), and the contents of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, leukotriene B4 (LTB4) and 6-keto-PGF-1α (degradation product of PGI2) in the gastric tissue.. Our data showed that C. butyricum significantly reduced the gastric mucosal injury area and ameliorated the pathological conditions of the gastric mucosa. C. butyricum not only minimized the decreases in activity of SOD and CAT, but also reduced the level of MDA in all three GU models used in this study. The accumulation of IL1-β, TNF-α and LBT4 decreased, while 6-keto-PGF-1α increased with pretreatment by C. butyricum in all three GU models.. Our data demonstrated the protective effects of pretreatment with C. butyricum on anti-oxidation and anti-inflammation in different types of GU models in mice. Further studies are needed to explore its potential clinical benefits.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Catalase; Clostridium butyricum; Cold Temperature; Disease Models, Animal; Ethanol; Gastric Mucosa; Gastritis; Inflammation Mediators; Interleukin-1beta; Leukotriene B4; Ligation; Male; Malondialdehyde; Mice, Inbred ICR; Omeprazole; Oxidative Stress; Probiotics; Proton Pump Inhibitors; Pylorus; Restraint, Physical; Stomach Ulcer; Superoxide Dismutase; Tumor Necrosis Factor-alpha

LTB4 is classified as a leukotriene (LT), a group of lipid mediators that are derived from arachidonic acid. It is recognized that leukotrienes are involved in the pathogenesis of many diseases, including peripheral inflammatory pain. However, little is known about the effects of leukotrienes on the spinal dorsal horn during neuropathic pain. Previously, we reported that there was increased expression of 5-lipoxygenase (5-LO) at spinal microglia, and the leukotriene B4 receptor 1 (BLT1), a high affinity receptor of LTB4, in spinal neurons in spared nerve injury (SNI) model rats. In the present study, we examined the effects of LTB4 on spinal dorsal horn neurons in both naïve and SNI model rats using patch-clamp methods.. Bath application of LTB4 did not change AMPA receptor-mediated spontaneous excitatory postsynaptic currents (sEPSCs) or membrane potentials. However, we found that LTB4 enhanced the amplitude of NMDA receptor-mediated sEPSCs and significantly increased exogenous NMDA-induced inward currents in SNI model rats. This increase of inward currents could be inhibited by a selective LTB4 antagonist, U75302, as well as a GDP-β-S, a G-protein inhibitor. These results indicate that both increased LTB4 from spinal microglia or increased BLT1 in spinal neurons after peripheral nerve injury can enhance the activity of NMDA receptors through intracellular G-proteins in spinal dorsal horn neurons.. Our findings showed that LTB4, which may originate from microglia, can activate BLT1 receptors which are expressed on the membrane of spinal dorsal horn neurons during neuropathic pain. This glia-neuron interaction induces the enhancement of NMDA currents through intracellular G-proteins. The enhancement of NMDA receptor sensitivity of dorsal horn neurons may lead to central sensitization, leading to mechanical pain hypersensitivity.

Topics: Animals; Disease Models, Animal; Excitatory Postsynaptic Potentials; GTP-Binding Proteins; Ion Channel Gating; Leukotriene B4; Male; N-Methylaspartate; Peripheral Nerve Injuries; Posterior Horn Cells; Rats, Sprague-Dawley; Receptors, AMPA; Receptors, Leukotriene; RNA, Messenger; Synapses; Synaptic Transmission

Acute bronchitis (AB) is a common lung condition characterized by inflammation of the large bronchi in response to infection. Bronchipret(®) syrup (BRO), a fixed combination of thyme and ivy extracts has been effectively used for the treatment of AB. Combining in vivo and mechanistic in vitro studies we aimed to provide a better understanding of the therapeutic potential of BRO on key aspects of AB and to identify potential mechanisms of action.. Bronchoalveolitis in rats was induced by intratracheal LPS instillation. BRO was administered p.o. once daily at 1- to 10-fold equivalents of the human daily dose. Animals were sacrificed 24-72 h post LPS challenge to analyze leukocyte numbers in lung tissue, bronchoalveolar lavage fluid (BALF) and blood as well as goblet cells in bronchial epithelium. Inhibitory effects of BRO analogue on leukotriene (LT) production were determined in human neutrophils and monocytes as well as on isolated 5-lipoxygenase (5-LO).. BRO significantly reversed the LPS-induced increase in leukocyte numbers in lung tissue, BALF and blood as well as goblet cell numbers in bronchial epithelium. In vitro, BRO analogue suppressed cellular release of LTB4 (IC50 = 36 µg⋅ml(-1)) and cysLT (IC50 = 10 µg⋅ml(-1)) and inhibited the activity of isolated 5-LO (IC50 = 19 µg⋅ml(-1)).. BRO exerts significant anti-inflammatory effects and attenuates goblet cell metaplasia in LPS-induced bronchoalveolitis in vivo potentially via interference with 5-LO/LT signaling. These effects may contribute to its observed clinical efficacy in AB.

Topics: Animals; Bronchitis; Bronchoalveolar Lavage Fluid; Cells, Cultured; Disease Models, Animal; Goblet Cells; Humans; Hyperplasia; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Male; Monocytes; Neutrophils; Plant Extracts; Rats; Rats, Wistar; Thymol; Thymus Plant

Myocardial infarction (MI) is one of the leading causes of death worldwide. Oxidative stress and inflammation play vital role in the development of MI. The Indian basil or Tulsi (Ocimum sanctum Linn.), owing to its antioxidant potential, is used in the traditional system of Indian medicine to treat various disorders. We evaluated methanolic extract of O. sanctum (Tulsi) leaves on inflammation in isoproterenol (ISP) induced MI in rats. ISP-induced MI increased the levels of cardiac markers, phospholipases and phospholipid content. However, the same were reduced on pre-treatment with methanolic extract of O. sanctum leaves. The activities of 5-lipoxygenase and cycloxygenase-2 and levels of leukotriene B4 and thromboxane B2 were also elevated in ISP-treated rats, which were significantly decreased (P < 0.001) in extract pre-treated rats. The enhanced mRNA expressions of nuclear factor kappa-B, 5-lipoxygenase activating protein and receptor for leukotriene B4 on MI induction, were considerably reduced (P < 0.001) on extract pre-treatment. Histopathological analysis also confirmed the findings. The results also revealed the high phenolic content of methanolic extract of O. sanctum leaves. The study demonstrated that methanolic extract of Tulsi leaves can decrease inflammation in the cardiac tissue of ISP-induced MI in rats and its effect may be through downregulation of oxidative stress and arachidonic acid pathway. This cardioprotective effect may be due to the high phenolic content of methanolic extract of O. sanctum leaves.

Topics: Animals; Antioxidants; Disease Models, Animal; Inflammation; Isoproterenol; Leukotriene B4; Male; Medicine, Traditional; Methanol; Myocardial Infarction; NF-kappa B; Ocimum; Oxidative Stress; Phenols; Phospholipids; Plant Extracts; Plant Leaves; Rats; Rats, Sprague-Dawley; RNA, Messenger; Thromboxane B2

Inflammatory responses to infection and injury must be restrained and negatively regulated to minimize damage to host tissue. One proposed mechanism involves enzymatic inactivation of the pro-inflammatory mediator leukotriene B4, but it is difficult to dissect the roles of various metabolic enzymes and pathways. A primary candidate for a regulatory pathway is omega oxidation of leukotriene B4 in neutrophils, presumptively by CYP4F3A in humans and CYP4F18 in mice. This pathway generates ω, ω-1, and ω-2 hydroxylated products of leukotriene B4, depending on species. We created mouse models targeting exons 8 and 9 of the Cyp4f18 allele that allows both conventional and conditional knockouts of Cyp4f18. Neutrophils from wild-type mice convert leukotriene B4 to 19-hydroxy leukotriene B4, and to a lesser extent 18-hydroxy leukotriene B4, whereas these products were not detected in neutrophils from conventional Cyp4f18 knockouts. A mouse model of renal ischemia-reperfusion injury was used to investigate the consequences of loss of CYP4F18 in vivo. There were no significant changes in infiltration of neutrophils and other leukocytes into kidney tissue as determined by flow cytometry and immunohistochemistry, or renal injury as assessed by histological scoring and measurement of blood urea nitrogen. It is concluded that CYP4F18 is necessary for omega oxidation of leukotriene B4 in neutrophils, and is not compensated by other CYP enzymes, but loss of this metabolic pathway is not sufficient to impact inflammation and injury following renal ischemia-reperfusion in mice.

Topics: Animals; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 4; Disease Models, Animal; Humans; Inflammation; Kidney; Leukotriene B4; Mice; Mice, Knockout; Neutrophils; Reperfusion Injury

Eicosanoids and sand fly saliva have a critical role in the Leishmania infection. Here, we evaluated the effect of Lutzomyia longipalpis salivary gland sonicate (SGS) on neutrophil and monocyte recruitment and activation of eicosanoid production in a murine model of inflammation.. C57BL/6 mice were inoculated intraperitonealy with Lutzomyia longipalpis SGS or Leishmania infantum or both, followed by analyses of cell recruitment, parasite load and eicosanoid production.. Intraperitoneal injection of Lutzomyia longipalpis SGS together with Leishmania infantum induced an early increased parasite viability in monocytes and neutrophils. L. longipalpis SGS increased prostaglandin E2 (PGE2), but reduced leukotriene B4 (LTB4) production ex vivo in peritoneal leukocytes. In addition, the pharmacological inhibition of cyclooxygenase 2 (COX-2) with NS-398 decreased parasite viability inside macrophages during Leishmania infection in the presence of L. longipalpis SGS arguing that PGE2 production is associated with diminished parasite killing.. These findings indicate that L. longipalpis SGS is a critical factor driving immune evasion of Leishmania through modulation of PGE2/LTB4 axis, which may represent an important mechanism on establishment of the infection.

Topics: Animals; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Female; Humans; Leishmania infantum; Leishmaniasis, Visceral; Leukocytes; Leukotriene B4; Macrophages; Male; Mice; Mice, Inbred C57BL; Nitrobenzenes; Psychodidae; Salivary Glands; Sulfonamides

Evidence suggests an important role of intestinal barrier dysfunction in the etiology of inflammatory bowel disease (IBD). Therefore stabilizing mucosal barrier function constitutes a new therapeutic approach in its management. Ectoine is a compatible solute produced by aerobic chemoheterotrophic and halophilic/halotolerant bacteria, where it acts as osmoprotectant and effective biomembrane stabilizer, protecting the producing cells from extreme environmental stress. Since this natural compound was also shown to prevent inflammatory responses associated with IBD, its potential usefulness was studied in a model of colitis. Groups of rats were treated orally with different doses of ectoine (30-300 mg/kg) or sulfasalazine (reference drug) daily for 11 days. On day 8 colitis was induced by intracolonic instillation of 2,4,6-trinitrobenzenesulfonic acid, when overt signs of lesions develop within the next 3 days. On day 12, blood was withdrawn from the retro-orbital plexus of the rats and the animals were sacrificed. The colon was excised and examined macroscopically and microscopically. Relevant parameters of oxidative stress and inflammation were measured in serum and colon homogenates. Induction of colitis led to marked weight loss, significant histopathological changes of the colon, and variable changes in levels of myeloperoxidase, reduced glutathione, malondialdehyde, and all inflammatory markers tested. Treatment with ectoine ameliorated the inflammatory changes in TNBS-induced colitis. This effect was associated with reduction in the levels of TNF-α, IL-1β, ICAM-1, PGE2 and LTB4. The findings suggest that intestinal barrier stabilizers from natural sources could offer new therapeutic measures for the management of IBD.

Topics: Amino Acids, Diamino; Animals; Body Weight; Colitis; Colon; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Glutathione; Intercellular Adhesion Molecule-1; Interleukin-1beta; Leukotriene B4; Male; Malondialdehyde; Rats; Rats, Wistar; Sulfasalazine; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha

Several emerging lines of evidence support an anti-inflammatory role for nicotinic acid (niacin); however, its role in the regulation of leukocyte migration in response to inflammatory stimuli has not been elucidated until now. Herein, we have examined the effect of nicotinic acid on neutrophil recruitment in experimentally induced inflammation. We demonstrated that nicotinic acid treatment inhibited interleukin (IL)-8-induced, leukotriene (LT)B4-induced, and carrageenan-induced neutrophil migration into the pleural cavity of BALB/c mice and reduced neutrophil rolling and adherence in a mouse cremaster muscle preparation. Surprisingly, nicotinic acid treatment increased the level of the neutrophil chemoattractant KC in response to carrageenan. These results suggest that nicotinic acid plays an important role in the regulation of inflammation due to its ability to inhibit the actions of the neutrophil chemoattractants IL-8 and LTB4. Further inhibition of chemoattractants leads to impairment of leukocyte rolling and adherence to the vascular endothelium in the microcirculation of inflamed tissues.

Topics: Animals; Anti-Inflammatory Agents; Carrageenan; Cell Adhesion; Chemokine CXCL1; Disease Models, Animal; Immune System Diseases; Inflammation; Interleukin-8; Leukocyte Disorders; Leukocyte Rolling; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Niacin; Pleural Cavity

Paracoccidioidomycosis is a human systemic mycosis caused by the fungus Paracoccidioides brasiliensis. The mechanisms involved in innate immune response to this fungus are not fully elucidated. Leukotrienes are known to be critical for the clearance of various microorganisms, mainly by mediating the microbicidal function of phagocytes. We investigated the involvement of leukotriene B4 in the early stages of experimental paracoccidioidomycosis, which was induced by intratracheal inoculation of the fungus in selected mouse lines. The mouse lines utilized were produced through bi-directional phenotypic selection, endowed with maximal or minimal acute inflammatory reactivity, and designated AIRmax and AIRmin, respectively. AIRmax mice were more resistant to the infection, which was demonstrated by reduced lung fungal loads. However, the two lines produced similar amounts of leukotriene B4, and pharmacological inhibition of this mediator provoked similar fungal load increases in the two lines. The lower fungal load in the AIRmax mice was associated with a more effective inflammatory response, which was characterized by enhanced recruitment and activation of phagocytic cells and an increased production of activator cytokines. This process resulted in an increased release of fungicidal molecules and a diminution of fungal load. In both lines, leukotriene production was associated with a protective response in the lung that was consequent to the effect of this eicosanoid on the influx and activation of phagocytes.

Topics: Animals; Colony Count, Microbial; Disease Models, Animal; Disease Resistance; Host-Pathogen Interactions; Leukotriene B4; Lung; Male; Mice; Paracoccidioides; Paracoccidioidomycosis; Phagocytosis

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

Leukotrienes (i.e., products of the 5-lipoxygenase pathway) are thought to be contributors to lung pathologies. Moreover, eosinophils have been linked with pulmonary leukotriene activities both as potential sources of these mediators and as responding effector cells. The objective of the present study was to define the role(s) of leukotrienes in the lung pathologies accompanying eosinophil-associated chronic respiratory inflammation. A transgenic mouse model of chronic T helper (Th) 2-driven inflammation expressing IL-5 from T cells and human eotaxin-2 locally in the lung (I5/hE2) was used to define potential in vivo relationships among eosinophils, leukotrienes, and chronic Th2-polarized pulmonary inflammation. Airway levels of cys-leukotrienes and leukotriene B4 (LTB4) are both significantly elevated in I5/hE2 mice. The eosinophil-mediated airway hyperresponsiveness (AHR) characteristic of these mice was abolished in the absence of leukotrienes (i.e., 5-lipoxygenase-deficient I5/hE2). More importantly, the loss of leukotrienes led to an unexpectedly significant decrease in collagen deposition (i.e., pulmonary fibrosis) that accompanied elevated levels of IL-4/-13 and TGF-β in the lungs of I5/hE2 mice. Further studies using mice deficient for the LTB4 receptor (BLT-1(-/-)/I5/hE2) and I5/hE2 animals administered a cys-leukotriene receptor antagonist (montelukast) demonstrated that the AHR and the enhanced pulmonary fibrosis characteristic of the I5/hE2 model were uniquely cys-leukotriene-mediated events. These data demonstrate that, similar to allergen challenge models of wild-type mice, cys-leukotrienes underlie AHR in this transgenic model of severe pulmonary Th2 inflammation. These data also suggest that an underappreciated link exists among eosinophils, cys-leukotriene-mediated events, and fibrotic remodeling associated with elevated levels of IL-4/-13 and TGF-β.

Topics: Animals; Arachidonate 5-Lipoxygenase; Bronchial Hyperreactivity; Chemokine CCL24; Disease Models, Animal; Eosinophils; Humans; Interleukin-5; Leukotriene B4; Leukotrienes; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Pneumonia; Pulmonary Fibrosis; Receptors, Leukotriene B4; Th2 Cells

Bronchial hyperresponsiveness is a hallmark of asthma and many factors modulate bronchoconstriction episodes. A potential correlation of formaldehyde (FA) inhalation and asthma has been observed; however, the exact role of FA remains controversial. We investigated the effects of FA inhalation on Ovalbumin (OVA) sensitisation using a parameter of respiratory mechanics. The involvement of nitric oxide (NO) and cyclooxygenase-derived products were also evaluated. The rats were submitted, or not, to FA inhalation (1%, 90 min/day, 3 days) and were OVA-sensitised and challenged 14 days later. Our data showed that previous FA exposure in allergic rats reduced bronchial responsiveness, respiratory resistance (Rrs) and elastance (Ers) to methacholine. FA exposure in allergic rats also increased the iNOS gene expression and reduced COX-1. L-NAME treatment exacerbated the bronchial hyporesponsiveness and did not modify the Ers and Rrs, while Indomethacin partially reversed all of the parameters studied. The L-NAME and Indomethacin treatments reduced leukotriene B₄ levels while they increased thromboxane B₂ and prostaglandin E₂. In conclusion, FA exposure prior to OVA sensitisation reduces the respiratory mechanics and the interaction of NO and PGE₂ may be representing a compensatory mechanism in order to protect the lung from bronchoconstriction effects.

Topics: Administration, Inhalation; Airway Resistance; Animals; Anti-Inflammatory Agents, Non-Steroidal; Bronchial Hyperreactivity; Bronchoconstrictor Agents; Cyclooxygenase 1; Dinoprostone; Disease Models, Animal; Eicosanoids; Formaldehyde; Gene Expression Regulation, Enzymologic; Leukotriene B4; Male; Membrane Proteins; Nitric Oxide; Nitric Oxide Synthase Type II; Rats; Rats, Wistar; Respiratory Insufficiency; Respiratory Mucosa; Thromboxane B2

Leukotrienes (LTs) produced from arachidonic acid by the action of 5-lipoxygenase (5-LO) are classical mediators of inflammatory responses. However, studies published in the literature regarding these mediators are contradictory and it remains uncertain whether these lipid mediators play a role in host defense against the fungal pathogen Paracoccidioides brasiliensis. To determine the involvement of LTs in the host response to pulmonary infection, wild-type and LT-deficient mice by targeted disruption of the 5-lipoxygenase gene (knockout mice) were studied following intratracheal challenge with P. brasiliensis yeasts. The results showed that infection is uniformly fatal in 5-LO-deficient mice and the mechanisms that account for this phenotype are an exacerbated lung injury and higher fungal pulmonary burden. Genetic ablation or pharmacological inhibition of LTs resulted in lower phagocytosis and fungicidal activity of macrophages in vitro, suggesting that deficiency in fungal clearance seems to be secondary to the absence of activation in 5-LO(-/-) macrophages. Exogenous LTB4 restored phagocytosis and fungicidal activity of 5-LO(-/-) macrophages. Moreover, P. brasiliensis killing promoted by LTB4 was dependent on nitric oxide (NO) production by macrophages. Taken together, these results reveal a fundamental role for 5-LO-derived LTB4 in the protective response to P. brasiliensis infection and identify relevant mechanisms for the control of fungal infection during the early stages of the host immune response.

Topics: Animals; Arachidonate 5-Lipoxygenase; Colony Count, Microbial; Disease Models, Animal; Leukotriene B4; Lung; Male; Mice; Mice, Knockout; Paracoccidioides; Paracoccidioidomycosis; Survival Analysis

This study was designed to determine the effects of peroxisome proliferator-activated receptor-gamma (PPARγ) on airway inflammatory response to cigarette smoke (CS) exposure.. For the in vivo experiments, 50 male Wistar rats were randomly assigned to one of four groups and were exposed to CS and pretreatment with a PPARγ agonist, rosiglitazone or a vehicle (saline). PPARγ antagonist bisphenol A diglycidyl ether (BADGE) or saline was administered before rosiglitazone treatment. Leukotriene B4 (LTB4) and interleukin-8 (IL-8) were measured by enzyme-linked immunosorbent assay. PPARγ and toll-like receptor 4 (TLR4) expression levels were assessed by immunohistochemistry and real-time polymerase chain reaction. For the in vitro experiments, human bronchial epithelial cells were stimulated with CS or phosphate buffer saline, pretreated with PPARγ agonist rosiglitazone or 15-deoxy-(Δ12,14)-PG J2 before CS exposure. BADGE was administered prior to the agonist treatment. PPARγ, TLR4 and inhibitor of κB (IκBα) expression levels were assessed by Western bot.. CS exposure decreased PPARγ expression, as well as increased IL-8, LTB4 and TLR4 expression levels in bronchial epithelial cells in vivo and in vitro. Moreover, PPARγ ligands counteracted CS-induced airway inflammation by reducing IL-8 and LTB4 expression levels that are associated with TLR4 and nuclear factor-kappa B (NF-κB).. CS exposure increased the pro-inflammatory activity of bronchial epithelial cells by affecting PPARγ expression. Moreover, PPARγ may play a significant role as a modulator of the TLR4-dependent inflammatory pathway through NF-κB in bronchial epithelial cells.

Topics: Animals; Benzhydryl Compounds; Bronchi; Cell Survival; Cells, Cultured; Disease Models, Animal; Down-Regulation; Epithelial Cells; Epoxy Compounds; In Vitro Techniques; Interleukin-8; Leukotriene B4; Male; NF-kappa B; Pneumonia; PPAR gamma; Rats; Rats, Wistar; Rosiglitazone; Smoking; Thiazolidinediones; Toll-Like Receptor 4; Up-Regulation

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

Our study aimed at the identification of anti-inflammatory activities of different fractions of C. sadleriana extract after per os administration in rats, the identification of the active compounds of the plant and the investigation of the in vitro anti-inflammatory activities of Centaurea species native to or cultivated in the Carpathian Basin. The aerial parts of Centaurea sadleriana Janka have been used in Hungarian folk medicine to treat the wounds of sheep. Methanol extract of C. sadleriana was fractioned by solvent-solvent partitioning. The n-hexane fraction was further fractionated and the anti-inflammatory activities of certain subfractions were confirmed in vivo in rats. The n-hexane and chloroform fraction of the methanol extract of C. sadleriana exhibited remarkable COX-1 and COX-2 inhibiting effects in vitro. Chromatographic separation of the fractions led to the identification of the active subfractions and 11 compounds (α-linolenic acid, γ-linolenic acid, stigmasterol, β-sitosterol, campesterol, vanillin, pectolinarigenin, salvigenin, hispidulin, chrysoeriol and apigenin). The in vitro screening for anti-inflammatory activities of further Centaurea species occurring in the Carpathian Basin (C. adjarica, C. bracteata, C. cataonica, C. cynaroides, C. dealbata, C. indurata, C. macrocephala, C. melitensis, C. nigrescens, C. ruthenica) revealed considerable COX-1 and COX-2 inhibitory activities. Because C. sadleriana is an endangered species native only to the Carpathian Basin, the investigation of more prevalent species is reasonable.

Topics: Animals; Anti-Inflammatory Agents; Centaurea; Chemical Fractionation; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Disease Models, Animal; Hungary; Leukotriene B4; Membrane Proteins; Plant Components, Aerial; Plant Extracts; Rats; Rats, Sprague-Dawley

Platelet-activating factor (PAF) and its receptor (PAFR) have been shown to be involved in several inflammatory events, including neutrophil chemoattraction and nociception. The present study addressed the role of PAF in the genesis of articular hyperalgesia in a model of joint inflammation. Zymosan-induced articular hyperalgesia, oedema and neutrophil migration were dose-dependently reduced following pretreatment with selective PAFR antagonists, UK74505 (5, 10 and 20 mg/kg) and PCA4248 (3, 10, 30 mg/kg). These parameters were also reduced in PAF receptor-deficient mice (PAFR(-/-)). The hyperalgesic action of PAF was further confirmed by the demonstration that joint injection of PAF induces a dose- (0.3, 1 and 3 μg/joint), time- and PAFR-dependent articular hyperalgesia and oedema. The PAF hyperalgesic mechanisms were dependent on prostaglandins, leukotrienes and neutrophils, as PAF-induced articular hyperalgesia was inhibited by indomethacin (COX inhibitor), MK886 (leukotrienes synthesis inhibitor) or fucoidan (leukocyte rolling inhibitor). Furthermore, PAF-induced hyperalgesia was reduced in 5-lypoxigenase-null mice. In corroboration of these findings, intra-articular injection of PAF promotes the production of LTB(4) as well as the recruitment of neutrophils to the joint. These results suggest that PAF may participate in the cascade of events involved in the genesis of articular inflammatory hyperalgesia via stimulation of prostaglandins, leukotrienes and neutrophil migration. Finally, targeting PAF action (e.g., with a PAFR antagonist) might provide a useful therapeutic approach to inhibit articular inflammatory hyperalgesia.

Topics: Animals; Dihydropyridines; Disease Models, Animal; Dose-Response Relationship, Drug; Hyperalgesia; Imidazoles; Immune System Diseases; Inflammation; Joint Diseases; Leukocyte Disorders; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Neutrophils; Platelet Activating Factor; Platelet Membrane Glycoproteins; Prostaglandins; Receptors, G-Protein-Coupled; Time Factors; Zymosan

Human genetics have implicated the 5-lipoxygenase enzyme in the pathogenesis of cardiovascular disease, and an inhibitor of the 5-lipoxygenase activating protein (FLAP) is in clinical development for asthma.. Here we determined whether FLAP deletion modifies the response to vascular injury.. Vascular remodeling was characterized 4 weeks after femoral arterial injury in FLAP knockout mice and wild-type controls. Both neointimal hyperplasia and the intima/media ratio of the injured artery were significantly reduced in the FLAP knockouts, whereas endothelial integrity was preserved. Lesional myeloid cells were depleted and vascular smooth muscle cell (VSMC) proliferation, as reflected by bromodeoxyuridine incorporation, was markedly attenuated by FLAP deletion. Inflammatory cytokine release from FLAP knockout macrophages was depressed, and their restricted ability to induce VSMC migration ex vivo was rescued with leukotriene B(4). FLAP deletion restrained injury and attenuated upregulation of the extracellular matrix protein, tenascin C, which affords a scaffold for VSMC migration. Correspondingly, the phenotypic modulation of VSMC to a more synthetic phenotype, reflected by morphological change, loss of α-smooth muscle cell actin, and upregulation of vascular cell adhesion molecule-1 was also suppressed in FLAP knockout mice. Transplantation of FLAP-replete myeloid cells rescued the proliferative response to vascular injury.. Expression of lesional FLAP in myeloid cells promotes leukotriene B(4)-dependent VSMC phenotypic modulation, intimal migration, and proliferation.

Topics: 5-Lipoxygenase-Activating Proteins; Animals; Bone Marrow Transplantation; Cell Movement; Cell Proliferation; Cells, Cultured; Cysteine; Disease Models, Animal; Endothelial Cells; Femoral Artery; Genotype; Hyperplasia; Inflammation Mediators; Leukotriene B4; Leukotrienes; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myeloid Cells; Myocytes, Smooth Muscle; Neointima; Phenotype; Tenascin; Time Factors; Vascular Cell Adhesion Molecule-1; Vascular System Injuries

The cholinergic antiinflammatory pathway (CAP), which terminates in the spleen, attenuates postoperative cognitive decline (PCD) in rodents. Surgical patients with metabolic syndrome exhibit exaggerated and persistent PCD that is reproduced in postoperative rats selectively bred for easy fatigability and that contain all features of metabolic syndrome (low-capacity runners [LCRs]). We compared the CAP and lipoxin A(4) (LXA(4)), another inflammation-resolving pathway in LCR, with its counterpart high-capacity runner (HCR) rats. Isoflurane-anesthetized LCR and HCR rats either underwent aseptic trauma involving tibial fracture (surgery) or not (sham). At postoperative d 3 (POD3), compared with HCR, LCR rats exhibited significantly exaggerated PCD (trace fear conditioning freezing time 43% versus 57%). Separate cohorts were killed at POD3 to collect plasma for LXA4 and to isolate splenic mononuclear cells (MNCs) to analyze CAP signaling, regulatory T cells (Tregs) and M2 macrophages (M2 Mφ). Under lipopolysaccharide (LPS) stimulation, tumor necrosis factor (TNF)-α produced by splenic MNCs was 117% higher in LCR sham and 52% higher in LCR surgery compared with HCR sham and surgery rats; LPS-stimulated TNF-α production could not be inhibited by an α7 nicotinic acetylcholine receptor agonist, whereas inhibition by the β(2) adrenergic agonist, salmeterol, was significantly less (-35%) than that obtained in HCR rats. Compared to HCR, sham and surgery LCR rats had reduced β(2) adrenergic receptor-expressing T lymphocytes (59%, 44%), Tregs (47%, 54%) and M2 Mφ (45%, 39%); surgical LCR rats' hippocampal M2 Mφ was 66% reduced, and plasma LXA4 was decreased by 120%. Rats with the metabolic syndrome have ineffective inflammation-resolving mechanisms that represent plausible reasons for the exaggerated and persistent PCD.

Topics: Animals; Anti-Inflammatory Agents; CD3 Complex; Cell Polarity; Choline; Cognition Disorders; Disease Models, Animal; Hippocampus; Inflammation; Leukotriene B4; Lipoxins; Lymphocyte Count; Macrophages; Male; Metabolic Syndrome; Physical Conditioning, Animal; Postoperative Period; Rats; Receptors, Adrenergic, beta-2; Signal Transduction; Spleen; T-Lymphocytes, Regulatory

Inflammation and reactive oxygen species are associated with the promotion of various cancers. The use of non-steroidal anti-inflammatory drugs (NSAIDs) in cancer prevention treatments has been promising in numerous cancers. We report the evaluation of NSAIDs chemically modified by the addition of a redox-active nitroxide group. TEMPO-aspirin (TEMPO-ASA) and TEMPO-indomethacin (TEMPO-IND) were synthesized and evaluated in the lung cancer cell line A549.. We evaluated physico-chemical properties of TEMPO-ASA and TEMPO-IND by electron paramagnetic resonance and cyclic voltammetry. Superoxide dismutase-like properties was assayed by measuring cytochrome c reduction and anti-inflammatory effects were assayed by measuring production of prostaglandin E(2) (PGE(2) ) and leukotriene B(4) (LTB(4) ). MTT proliferation assay and clonogenic assay were evaluated in the A549 lung carcinoma cell line. Maximum tolerated doses (MTD) and acute ulcerogenic index were also evaluated in in vivo.. MTD were: TEMPO (140 mg·kg(-1) ), ASA (100 mg·kg(-1) ), indomethacin (5 mg·kg(-1) ), TEMPO-ASA (100 mg·kg(-1) ) and TEMPO-IND (40 mg·kg(-1) ). While TEMPO-ASA was as well tolerated as ASA, TEMPO-IND showed an eightfold improvement over indomethacin. TEMPO-IND showed markedly less gastric toxicity than the parent NSAID. Both TEMPO-ASA and TEMPO-IND inhibited production of PGE(2) and LTB(4) in A549 cells with maximum effects at 100 µg·mL(-1) or 10 µg·mL(-1) respectively.. The nitroxide-NSAIDs retained superoxide scavenging capacity of the parent nitroxide and anti-inflammatory effects, inhibiting cyclooxygenase and 5-lipoxygenase enzymes. These redox-modified NSAIDs might be potential drug candidates, as they exhibit the pharmacological properties of the parent NSAID with antioxidant activity decreasing NSAID-associated toxicity.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Aspirin; Carrageenan; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclic N-Oxides; Dinoprostone; Disease Models, Animal; Edema; Female; Humans; Indomethacin; Leukotriene B4; Mice; Mice, Nude; Rats; Stomach Ulcer; Superoxide Dismutase

Susceptibility to tuberculosis is historically ascribed to an inadequate immune response that fails to control infecting mycobacteria. In zebrafish, we find that susceptibility to Mycobacterium marinum can result from either inadequate or excessive acute inflammation. Modulation of the leukotriene A(4) hydrolase (LTA4H) locus, which controls the balance of pro- and anti-inflammatory eicosanoids, reveals two distinct molecular routes to mycobacterial susceptibility converging on dysregulated TNF levels: inadequate inflammation caused by excess lipoxins and hyperinflammation driven by excess leukotriene B(4). We identify therapies that specifically target each of these extremes. In humans, we identify a single nucleotide polymorphism in the LTA4H promoter that regulates its transcriptional activity. In tuberculous meningitis, the polymorphism is associated with inflammatory cell recruitment, patient survival and response to adjunctive anti-inflammatory therapy. Together, our findings suggest that host-directed therapies tailored to patient LTA4H genotypes may counter detrimental effects of either extreme of inflammation.

Topics: Animals; Disease Models, Animal; Humans; Inflammation; Leukotriene A4; Leukotriene B4; Lipoxins; Mitochondria; Mycobacterium Infections; Mycobacterium marinum; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Promoter Regions, Genetic; Signal Transduction; Transcription, Genetic; Tuberculosis, Meningeal; Tumor Necrosis Factor-alpha; Zebrafish

Cecal ligation and puncture (CLP) is an inflammatory condition that leads to multisystemic organ failure. Flavocoxid, a dual inhibitor of cyclooxygenase (COX-2) and 5-lipoxygenase (5-LOX), has been shown in vitro to possess antiinflammatory activity in lipopolysaccharide (LPS)-stimulated rat macrophages by reducing nuclear factor (NF)-κB activity and COX-2, 5-LOX and inducible nitric oxide synthase (iNOS) expression. The aim of this study was to evaluate the effects of flavocoxid in a murine model of CLP-induced polymicrobial sepsis.. C57BL/6J mice were subjected to CLP or sham operation. In a first set of experiments, an intraperitoneal injection of flavocoxid (20 mg/kg) or vehicle was administered 1 hour after surgery and repeated every 12 hours. Survival rate was monitored every 24 hours throughout 120 hours. Furthermore, additional groups of sham and CLP mice were killed 18 hours after surgical procedures for blood-sample collection and the lung and liver were collected for biomolecular, biochemical and histopathologic studies.. COX-2, 5-LOX, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-10, extracellular-regulated-kinase 1/2 (ERK), JunN-terminal kinase (JNK), NF-κB, and β-arrestin 2 protein expression were evaluated in lung and liver with Western blot analysis. In addition, leukotriene B4 (LTB4), prostaglandin E2 (PGE2), cytokines, and lipoxin A4 serum content were measured with an enzyme-linked immunosorbent assay (ELISA). Flavocoxid administration improved survival, reduced the expression of NF-κB, COX-2, 5-LOX, TNF-α and IL-6 and increased IL-10 production. Moreover, flavocoxid inhibited the mitogen-activated protein kinases (MAPKs) pathway, preserved β-arrestin 2 expression, reduced blood LTB4, PGE2, TNF-α and IL-6, and increased IL-10 and lipoxin A4 serum levels. The treatment with flavocoxid also protected against the histologic damage induced by CLP and reduced the myeloperoxidase (MPO) activity in the lung and liver.. Flavocoxid protects mice from sepsis, suggesting that this dual inhibitor may represent a promising approach in such a life-threatening condition.

Topics: Animals; Arrestins; beta-Arrestin 2; beta-Arrestins; Catechin; Cyclooxygenase 2 Inhibitors; Cytokines; Dinoprostone; Disease Models, Animal; Drug Combinations; Extracellular Signal-Regulated MAP Kinases; Intracellular Signaling Peptides and Proteins; Leukotriene B4; Lipoxins; Lipoxygenase Inhibitors; Liver; Lung; Mice, Inbred C57BL; NF-kappa B; Peroxidase; Sepsis

Itching of ocular allergy is alleviated but not completely relieved by H(1) histamine receptor antagonists, suggesting that histamine is not the sole itch mediator in ocular allergy. We investigated whether leukotriene B(4) (LTB(4)), a mediator of cutaneous itch, is involved in the itch of ocular allergy in mice. Mice were immunized by the repeated subcutaneous injections of ragweed pollen and alum into the caudal back, and given a subconjunctival injection of ragweed pollen extract into the palpebra for allergic challenge. Challenge with ragweed pollen extract markedly elicited ocular scratching in sensitized mice. The scratching was almost abolished by mast cell deficiency. The H(1) antagonist terfenadine partially inhibited scratching at a dose that almost completely suppressed plasma extravasation. Scratching was inhibited by the glucocorticoid betamethasone and the 5-lipoxygenase inhibitor zileuton at doses that inhibited the challenge-induced production of LTB(4). A subconjunctival injection of LTB(4) at doses 1/10,000 or less than that required for histamine elicited ocular scratching in naïve mice. The LTB(4) receptor antagonist ONO-4057 inhibited the ragweed pollen challenge-induced ocular scratching at doses that suppressed LTB(4)-induced ocular scratching. In addition to histamine, LTB(4) is involved in the ocular itching of pollen allergy. H(1) receptor antagonists with an inhibitory effect on the action and/or production of LTB(4) may have more potent anti-pruritic activity than selective H(1) antagonists.

Topics: Allergens; Ambrosia; Animals; Conjunctivitis, Allergic; Disease Models, Animal; Glucocorticoids; Histamine; Histamine H1 Antagonists, Non-Sedating; Hydroxyurea; Immunoglobulin E; Immunoglobulin G; Immunosuppressive Agents; Injections, Intraocular; Injections, Subcutaneous; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mast Cells; Mice; Mice, Inbred ICR; Phenylpropionates; Pollen; Terfenadine

Several emerging lines of evidence support an anti-inflammatory role for nicotinamide and other vitamin B components. However, the mechanisms underlying their activity remain unclear. In the present study, we investigated the ability of nicotinamide to inhibit both neutrophil recruitment in IL-8-, LTB(4)- or carrageenan-induced pleurisy in mice and the rolling and adherence of neutrophils. Nicotinamide inhibited IL-8-, LTB(4)- and carrageenan-induced neutrophil migration, KC production and carrageenan-induced neutrophil rolling and adherence. We propose that the effects of nicotinamide in inhibiting neutrophil recruitment in carrageenan-induced pleurisy may be due to the ability of nicotinamide to inhibit the action of IL-8 and LTB(4), decrease KC production, and inhibit early events that regulate leukocyte migration from blood vessels into tissue.

Topics: Animals; Anti-Inflammatory Agents; Carrageenan; Cell Adhesion; Disease Models, Animal; Interleukin-8; Leukocyte Rolling; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Niacinamide; Pleurisy

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

Epigallocatechin-3-gallate (EGCG), atorvastatin (ATST), and their combination have been previously shown to inhibit colon carcinogenesis in animal models. We further investigated their inhibitory activities in azoxymethane (AOM) and dextran sulfate sodium (DSS)-treated Balb/cJ mice and CD-1 mice in 2 slightly different models. The mice were maintained on the AIN93M diet, or a similar diet containing 0.03%, 0.1%, or 0.3% EGCG; 60-ppm ATST; or a combination of 0.1% EGCG and 60-ppm ATST. Unexpectedly, no significant inhibitory activity was observed, and some of the treatment groups resulted in higher tumor multiplicity. To study the effects of EGCG on colon inflammation, CD-1 or C57BL/6 mice were treated with 1.5% DSS for 7 days and sacrificed 3 days later. DSS induced rectal bleeding and colon shortening; treatment with 0.5% EGCG exacerbated the bleeding and decreased mouse body weight. Dietary 0.5% EGCG also increased serum levels of leukotriene B4 and prostaglandin E2. These results suggest that, in mice bearing colon inflammation, high concentrations of EGCG and ATST enhance colon bleeding and may promote colon carcinogenesis.

Topics: Animals; Atorvastatin; Azoxymethane; Catechin; Colitis; Colon; Colonic Neoplasms; Dextran Sulfate; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Gastrointestinal Hemorrhage; Heptanoic Acids; Leukotriene B4; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Pyrroles; Rectum; Weight Loss

Scratching triggers skin flares in atopic dermatitis. We demonstrate that scratching of human skin and tape stripping of mouse skin cause neutrophil influx. In mice, this influx was largely dependent on the generation of leukotriene B4 (LTB4) by neutrophils and their expression of the LTB4 receptor BLT1. Allergic skin inflammation in response to epicutaneous (EC) application of ovalbumin to tape-stripped skin was severely impaired in Ltb4r1(-/-) mice and required expression of BLT1 on both T cells and non-T cells. Cotransfer of wild-type (WT) neutrophils, but not neutrophils deficient in BLT1 or the LTB4-synthesizing enzyme LTA4H, restored the ability of WT CD4(+) effector T cells to transfer allergic skin inflammation to Ltb4r1(-/-) recipients. Pharmacologic blockade of LTB4 synthesis inhibited allergic skin inflammation elicited by cutaneous antigen challenge in previously EC-sensitized mice. Our results demonstrate that a neutrophil-T cell axis reliant on LTB4-BLT1 interaction is required for allergic skin inflammation.

Topics: Animals; Biopsy; Dermatitis; Disease Models, Animal; Humans; Leukotriene B4; Mice; Mice, Inbred C57BL; Neutrophil Infiltration; Neutrophils; Receptors, Leukotriene B4

Previous studies have shown gastroprotective effect of fish oil in several experimental models. However, the mechanisms and active compounds underlying this effect are not fully understood. Fish oil has several components; among them, one of the most studied is docosahexaenoic acid (DHA), which is an omega-3 long-chain polyunsaturated fatty acid. The aim of this study was to examine the gastroprotective effect of DHA as a pure compound in a rat model of indomethacin-induced gastric injury as well as elucidate some of the mechanism(s) behind DHA's gastroprotective effect. Indomethacin was orally administered to induce an acute gastric injury (3, 10 and 30mg/kg). Omeprazol (a proton pump inhibitor, 30mg/kg, p.o.) and DHA (3, 10, 30mg/kg, p.o.) were gavaged 30 and 120min, respectively, before indomethacin insult (30mg/kg p.o.). Three hours after indomethacin administration, rats were sacrificed, gastric injury was evaluated by determining the total damaged area. A sample of gastric tissue was harvested and processed to quantify prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) levels by enzyme-linked immunosorbent assay. Indomethacin produced gastric injury in dose-dependent manner. DHA protected against indomethacin-induced gastric damage, and this effect was comparable with omeprazol's gastroprotective effect. DHA did not reverse the indomethacin-induced reduction of PGE(2) gastric levels. In contrast, DHA partially prevented the indomethacin-induced increase in LTB(4) gastric levels. This is the first report demonstrating DHA's gastroprotective effect as a pure compound. Furthermore, the results reveal that the gastroprotective effect is mediated by a decrease in gastric LTB(4) levels in indomethacin-induced gastric damage.

Topics: Administration, Oral; Animals; Anti-Ulcer Agents; Cytoprotection; Dinoprostone; Disease Models, Animal; Docosahexaenoic Acids; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Female; Gastric Mucosa; Indomethacin; Leukotriene B4; Omeprazole; Proton Pump Inhibitors; Rats; Rats, Wistar; Stomach; Stomach Ulcer; Time Factors

Aloe has been a very popular folk remedy for inflammation-related pathological conditions despite the lack of studies reporting its efficacy in vivo. The present study evaluated the anti-inflammatory effects of aloe components (aloin, aloesin and aloe-gel) known to be biologically active in the rat model of colitis.. Male Sprague Dawley rats were fed experimental diets for 2 weeks before and during the induction of colitis. Drinking water containing 3% dextran sulfate sodium (DSS) was provided for 1 week to induce colitis. At the end of the experimental period, clinical and biochemical markers were compared.. Plasma leukotriene B(4) (LTB(4)) and tumor necrosis factor-α (TNF-α) concentrations were significantly decreased in all groups supplemented with aloe components compared to the colitis control group (p<0.05). Animals fed both a 0.1% and 0.5% aloesin supplemented diet showed colonic myeloperoxidase (MPO) activities which were decreased by 32.2% and 40.1%, respectively (p<0.05). Colonic mucosa TNF-α and interleukin-1ß (IL-1β) mRNA expressions were significantly reduced in all animals fed aloin, aloesin, or aloe-gel (p<0.05).. Dietary supplementation of aloe components ameliorates intestinal inflammatory responses in a DSS-induced ulcerative colitis rat model. In particular, aloesin was the most potent inhibitor. Further studies are required for a more complete understanding of the specific mechanism of the action of these supplements.

Topics: Aloe; Animals; Anti-Inflammatory Agents, Non-Steroidal; Chromones; Colitis; Colon; Diet; Dietary Supplements; Disease Models, Animal; Emodin; Gels; Glucosides; Interleukin-1beta; Leukotriene B4; Male; Peroxidase; Plant Preparations; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha

Glomerular infiltration of macrophages is a characteristic alteration of renal pathology in hyperlipidaemic renal injury. Leukotriene B4 (LTB4) is a bioactive eicosanoid and macrophage and has two key enzymes for LTB4 synthesis, 5-lipoxygenase and leukotriene A4 (LTA4) hydrolase. The purpose of this study was to evaluate the role of LTB4 in accelerated hyperlipidaemic renal injury.. To induce accelerated hyperlipidaemic renal injury, 8 week old male spontaneously hypercholesterolaemic (SHC) rats were fed with a high cholesterol diet for 6 weeks. LTA4 hydrolase activities in the kidney and urine LTB4 levels were examined. The effects of LTB4 antagonist (ONO-4057) were also evaluated.. Urinary protein and LTB4 excretion was increased by a high cholesterol diet for 6 weeks. The scores of glomerular foam cell accumulation and sclerosis, numbers of infiltrated macrophages in glomeruli and interstitial area, LTA4 hydrolase activity in renal cortex were higher in the high cholesterol diet group than the normal diet group. LTB4 antagonist treatment reduced urinary protein and LTA4 activity and attenuated renal pathological changes.. These results suggest that LTB4 directly contributes to accelerated hyperlipidaemic renal injury and the therapeutic potential of LTB4 antagonist for renal damage induced by hyperlipidaemia.

Topics: Animals; Blood Pressure; Body Weight; Disease Models, Animal; Epoxide Hydrolases; Foam Cells; Hypercholesterolemia; Kidney Diseases; Kidney Glomerulus; Leukotriene Antagonists; Leukotriene B4; Male; Phenylpropionates; Proteinuria; Rats; Time Factors

We tested the hypothesis that leukotriene B4 (LTB4) mediates pancreatic inflammation in rats via activation of the transient receptor potential vanilloid 1 (TRPV1).. Leukotriene B4 or a vehicle was administered to adult rats via celiac axis injection after pretreatment with the TRPV1 antagonist, capsazepine, or vehicle, and the severity of subsequent pancreatitis was assessed by measuring pancreatic edema, myeloperoxidase (MPO) activity, and histological grading. In a second experiment, acute pancreatitis was induced by common pancreaticobiliary duct ligation. Six hours after surgery, pancreatic tissue levels of LTB4 were determined by enzyme-linked immunosorbent assay. Also, the effects of inhibition of LTB4 biosynthesis by pretreatment with the 5-lipoxygenase-activating peptide inhibitor, MK-886, were determined.. Celiac axis administration of LTB4 significantly increased pancreatic edema and MPO activity, and produced histological evidence of pancreatic edema, neutrophil infiltration, and necrosis. Capsazepine pretreatment significantly reduced all inflammatory parameters in LTB4-induced pancreatitis. Pancreatic tissue levels of LTB4 were significantly elevated in rats that underwent common pancreaticobiliary duct ligation compared with control rats. MK-886 pretreatment significantly inhibited pancreatic edema, histological damage, and pancreatic MPO concentrations.. Common pancreaticobiliary duct obstruction causes an increase in pancreatic LTB4 concentrations that in turn mediates activation of TRPV1 resulting in acute pancreatitis.

Topics: Animals; Capsaicin; Cholestasis; Disease Models, Animal; Indoles; Inflammation Mediators; Leukotriene B4; Ligation; Lipoxygenase Inhibitors; Male; Models, Biological; Pancreatitis; Peroxidase; Rats; Rats, Sprague-Dawley; TRPV Cation Channels

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

To elucidate the mechanisms of severe itch in atopic dermatitis, we investigated the role of leukotriene B(4) , a potent itch mediator, in spontaneous itch-related behaviour in NC mice with atopic dermatitis-like skin lesions. Topical application of the BLT leukotriene B(4) receptor antagonist ONO-4057 inhibited spontaneous itch-related behaviour. The concentration of leukotriene B(4) was significantly increased in the lesional skin. The expression levels of 5-lipoxygenase were also elevated in the lesional skin, yet present throughout the epidermis of both healthy and lesional skin. These results suggest a role for leukotriene B(4) in chronic dermatitis-related itch. Sphingosylphosphorylcholine (SPC) was increased in the epidermis of the lesional skin. Moreover, intradermal injection of SPC elicited itch-related behaviours in healthy mice. Because SPC induces itch-related responses through the production of leukotriene B(4) in keratinocytes (J Invest Dermatol, 129, 2009, 2854), these results suggest that an increase in SPC induces leukotriene B(4) -mediated itching in chronic dermatitis. BLT1 receptor and 5-lipoxygenase in the skin may be effective pharmacological targets for the treatment of itch in atopic dermatitis.

Topics: Administration, Topical; Animals; Arachidonate 5-Lipoxygenase; Dermatitis, Atopic; Disease Models, Animal; Leukotriene B4; Mice; Phenylpropionates; Phosphorylcholine; Pruritus; Receptors, Leukotriene B4; Skin; Sphingosine

Aristolochia tagala Cham. (syn: Aristolochia acuminata Lam.) (Aristolochiaceae), known as Nallayishwari in Telugu, has been of interest to researchers because of its traditional uses for treating rheumatic pains and fever.. The anti-inflammatory activity of the petroleum ether, ethyl acetate, and ethanol extracts of A. tagala roots were investigated for the first time.. In vivo and in vitro anti-inflammatory effects were investigated employing the carrageenan-induced hind paw edema in rats and the macrophage cell line RAW264.7 stimulated with proinflammatory stimuli (lipopolysaccharide interferon γ or the calcium ionophore A23187) to determine PGE(2) or LTB(4) release, respectively.. All the extracts exhibited anti-inflammatory effects which were found to be significant (p < 0.001) at 200 and 400 mg/kg, p.o, in rats tested and the ethyl acetate extract inhibited the induction of PGE(2) with IC(50) = 39.1 mg mL(-1) and LTB(4) with IC(50) = 29.5 mg mL(-1).. These findings demonstrate that the A. tagala roots have excellent anti-inflammatory activity and validate the traditional indications of this plant in its origin country.

Topics: Acetates; Alkanes; Animals; Anti-Inflammatory Agents; Aristolochia; Calcimycin; Calcium Ionophores; Carrageenan; Cell Line; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Ethanol; Female; Inflammation; Interferon-gamma; Leukotriene B4; Macrophages; Male; Mice; Plant Extracts; Plant Roots; Plants, Medicinal; Rats; Rats, Wistar; Time Factors

The aim of this study is to verify the crucial role of cytosolic phospholipase A2 alpha (cPLA2 alpha) in the pathogenesis of collagen-induced arthritis in mice and to determine the anti-arthritic effects of pyrroxyphene, a cPLA2 alpha inhibitor.. Pyrroxyphene was administered (p.o.) twice a day for 18 days at 30 and 100 mg/kg. Its effects on arthritic symptoms, bone destruction, cPLA2 alpha activity, levels of prostaglandin E(2) and leukotriene B(4), and mRNA expression of matrix metalloproteinase (MMP)-3, -8, -9, -13 and cyclooxygenase-2 (COX-2) were tested.. cPLA2 alpha activity gradually increased and showed a correlation with the severity of arthritis. Pyrroxyphene strongly inhibited the incidence of arthritis and bone destruction. Moreover, it significantly inhibited both the increase in levels of cPLA2 alpha and eicosanoids as well as the mRNA expression of MMP-3, -8, -9, -13, and COX-2.. These results demonstrate that cPLA2 alpha plays an important role in the pathogenesis of collagen-induced arthritis. Oral administration of pyrroxyphene achieved anti-arthritic activity through inhibition of cPLA2 alpha activity, which led to a reduction in eicosanoid levels and suppression of MMP and COX-2 mRNA expression. These results support a potential therapeutic role for cPLA2 alpha inhibitors in the treatment of human rheumatoid arthritis.

Topics: Animals; Arthritis, Experimental; Bone Diseases; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Eicosanoids; Enzyme Inhibitors; Group IV Phospholipases A2; Leukotriene B4; Male; Matrix Metalloproteinases; Mice; Mice, Inbred DBA; Pyrrolidines; Thiazolidinediones

Animal and clinical studies have suggested that polyphenols in fruits, red wine, and tea may delay the development of atherosclerosis through their antioxidant and anti-inflammatory properties. We investigated whether individual dietary polyphenols representing different polyphenolic classes, namely quercetin (flavonol), (-)-epicatechin (flavan-3-ol), theaflavin (dimeric catechin), sesamin (lignan), or chlorogenic acid (phenolic acid), reduce atherosclerotic lesion formation in the apolipoprotein E (ApoE)(-/-) gene-knockout mouse.. Quercetin and theaflavin (64-mg/kg body mass daily) significantly attenuated atherosclerotic lesion size in the aortic sinus and thoracic aorta (P<0.05 versus ApoE(-/-) control mice). Quercetin significantly reduced aortic F(2)-isoprostane, vascular superoxide, vascular leukotriene B(4), and plasma-sP-selectin concentrations; and augmented vascular endothelial NO synthase activity, heme oxygenase-1 protein, and urinary nitrate excretion (P<0.05 versus control ApoE(-/-) mice). Theaflavin showed similar, although less extensive, significant effects. Although (-)-epicatechin significantly reduced F(2)-isoprostane, superoxide, and endothelin-1 production (P<0.05 versus control ApoE(-/-) mice), it had no significant effect on lesion size. Sesamin and chlorogenic acid treatments exerted no significant effects. Quercetin, but not (-)-epicatechin, significantly increased the expression of heme oxygenase-1 protein in lesions versus ApoE(-/-) controls.. Specific dietary polyphenols, in particular quercetin and theaflavin, may attenuate atherosclerosis in ApoE(-/-) gene-knockout mice by alleviating inflammation, improving NO bioavailability, and inducing heme oxygenase-1. These data suggest that the cardiovascular protection associated with diets rich in fruits, vegetables, and some beverages may in part be the result of flavonoids, such as quercetin.

Topics: Animals; Anti-Inflammatory Agents; Aorta; Aortic Diseases; Apolipoproteins E; Atherosclerosis; Biflavonoids; Biomarkers; Catechin; Chlorogenic Acid; Cholesterol; Diet; Dioxoles; Disease Models, Animal; Endothelin-1; Endothelium, Vascular; F2-Isoprostanes; Fatty Acids; Flavonoids; Heme Oxygenase-1; Inflammation; Leukotriene B4; Lignans; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitrates; Nitric Oxide; Nitric Oxide Synthase Type III; Nitrites; Oxidative Stress; P-Selectin; Phenols; Polyphenols; Quercetin; Superoxides

Despite intensive studies focused on the pathophysiology of asthmatic inflammation, little is known about how cross-talk between neuroendocrine and immune systems regulates the inflammatory response during an asthmatic attack. We recently showed corresponding changes of cytokines and leukotriene B4 (LTB4) in brain and lung tissues of antigen-challenged asthmatic rats. Here, we investigated how LTB4 interacts with the neuroendocrine-immune system in regulating antigen-induced asthmatic responses in sensitized guinea pigs.. Ovalbumin-sensitized guinea pigs were challenged by inhalation of antigen. Vehicle, LTB4 or U75302 (a selective LTB4 BLT1 receptor inhibitor) was given via intracerebroventricular injection (i.c.v.) 30 min before challenge. Airway contraction response was evaluated using Penh values before and after antigen challenge. The inflammatory response in lung tissue was evaluated 24 h after challenge. The LTB4 content of lung and brain homogenate preparations was detected by reversed phase high-performance liquid chromatography (RP-HPLC). Plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were measured using ELISA kits.. Antigen challenge impaired pulmonary function and increased inflammatory cell infiltration in lung tissue. These responses could be significantly suppressed by LTB4, 30 ng i.c.v., in ovalbumin-sensitized guinea pigs. LTB4 content of lung and brain homogenates from antigen-challenged guinea pigs was significantly increased. In addition, administration of LTB4 via i.c.v. markedly increased CORT and ACTH level in plasma before antigen challenge, and there were further increases in CORT and ACTH levels in plasma after antigen challenge. U75302, 100 ng i.c.v., completely blocked the effects of LTB4. In addition, U75302, 100 ng via i.c.v. injection, markedly decreased LTB4 content in lung homogenates, but not in brain homogenates.. Increased LTB4 levels in brain during asthmatic attacks down-regulates airway contraction response and inflammation through the BLT1 receptor. Stimulation of the hypothalamic-pituitary-adrenal axis by LTB4 may result in an increase in systemic glucocorticoids which, in turn, would feed back to suppress the asthmatic response.

Topics: Adrenocorticotropic Hormone; Analysis of Variance; Animals; Asthma; Bronchoalveolar Lavage Fluid; Chromatography, Reverse-Phase; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Fatty Alcohols; Glycols; Guinea Pigs; Hydrocortisone; Injections, Intraventricular; Intracranial Hemorrhages; Leukotriene B4; Lung; Ovalbumin; Time Factors

Canine atopic dermatitis (AD), a chronic inflammatory skin disease, shares characteristics with its human counterpart. To get insight into the role of enzymes involved in production of prostaglandin E(2) (PGE2) and leukotriene B(4) (LTB(4)), potent inflammatory mediators originating from membrane-derived arachidonic acid (AA), expression of genes encoding these enzymes and receptors was quantified by qPCR in non-lesional and lesional skin from atopic dogs and in healthy skin. Significantly higher mRNA expression of the key enzymes 5-lipoxygenase (5-LO), 5-LO activating protein (FLAP), leukotriene A(4) hydrolase (LTA(4)H) and prostaglandin E synthase 1 (mPGES-1) and their receptors (PGE receptors 2 and 3) were observed. Being responsible for elevated levels of metabolites of the 3-series prostaglandins and the 5-series leukotrienes these enzymes may be interesting targets for therapy that should result in amelioration of clinical signs in canine atopic dermatitis.

Topics: 5-Lipoxygenase-Activating Proteins; Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Dermatitis, Atopic; Dinoprostone; Disease Models, Animal; Dogs; Eicosanoids; Epoxide Hydrolases; Interleukin-6; Intramolecular Oxidoreductases; Leukotriene B4; Prostaglandin-E Synthases; Skin

We investigated the effects of vaporized perfluorohexane (PFH) on pulmonary vascular tone, pulmonary vascular resistance and peak inspiratory pressure as well as lipid mediator formation in the treatment of calcium ionophore induced lung injury in a model of the isolated perfused and ventilated rabbit lungs.. Lung injury was induced in isolated perfused and ventilated rabbit lungs by calcium ionophore A23187. Lungs were treated with either 4.5 vol.% (4.5 vol.% PFH; n = 6) or 18 vol.% (18 vol.% PFH; n = 6) PFH. Six lungs remained untreated (Control). In addition 5 lungs (PFH-sham) remained uninjured receiving 18 vol.% PFH only. Mean pulmonary artery pressure (mPAP), peak inspiratory pressure (P(max)), and lung weight (weight) were monitored for 120 min. Experiments were terminated before when the increase in lung weight exceeded 40 g. Perfusate samples were taken at regular intervals for analysis of TXB(2), 6-keto-PGF(1) and LTB(4).. Controls reached the study end point significantly earlier than both PFH groups. Significant differences were found for a weight gain of 10 g and 20 g between the control and the 4.5 vol.% PFH and the 18 vol.% PFH. Differences in mPAP were more pronounced in the 4.5 vol.% PFH. However increases in P(max) were more marked in 4.5 vol.% PFH. TXA(2)-, PGI(2)-, and LTB(4)-levels were significantly lower in PFH groups. Uninjured lungs remained unaffected by the presence of 18 vol.% PFH.. Inflammatory lung injury was attenuated by the treatment with 4.5 vol.% PFH and 18 vol.% PFH vapor in the isolated perfused rabbit lung. Therapeutic effects were more pronounced with a concentration of 4.5 vol.% PFH.

Topics: Animals; Calcimycin; Disease Models, Animal; Dose-Response Relationship, Drug; Epoprostenol; Female; Fluorocarbons; In Vitro Techniques; Ionophores; Leukotriene B4; Lung; Lung Injury; Organ Size; Positive-Pressure Respiration; Pulmonary Artery; Pulmonary Circulation; Pulmonary Edema; Rabbits; Thromboxane A2; Vascular Resistance; Volatilization

5-Lipoxygenase (LOX) is an important arachidonic acid-metabolizing enzyme producing leukotrienes and other proinflammatory lipid mediators with potent pathophysiological functions in asthma and other inflammatory diseases. 4-(3-(4-(1-Methyl-1H-pyrazol-5-yl)phenylthio)phenyl)-tetrahydro-2H-pyran-4-carboxamide (PF-4191834) is a novel, selective non-redox 5-lipoxygenase inhibitor effective in inflammation and pain. In vitro and in vivo assays were developed for the evaluation of a novel 5-LOX inhibitor using conditions of maximal enzyme activity. PF-4191834 exhibits good potency in enzyme- and cell-based assays, as well as in a rat model of acute inflammation. Enzyme assay results indicate that PF-4191834 is a potent 5-LOX inhibitor, with an IC(50) = 229 +/- 20 nM. Furthermore, it demonstrated approximately 300-fold selectivity for 5-LOX over 12-LOX and 15-LOX and shows no activity toward the cyclooxygenase enzymes. In addition, PF-4191834 inhibits 5-LOX in human blood cells, with an IC(80) = 370 +/- 20 nM. This inhibitory concentration correlates well with plasma exposures needed for in vivo efficacy in inflammation in models of inflammatory pain. The combination of potency in cells and in vivo, together with a sustained in vivo effect, provides PF-4191834 with an overall pharmacodynamic improvement consistent with once a day dosing.

Topics: Animals; Asthma; Chromatography, Liquid; Disease Models, Animal; Humans; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mass Spectrometry; Oxidation-Reduction; Pain; Pyrazoles; Rats; Rats, Inbred Lew; Rats, Sprague-Dawley; Spectrophotometry; Sulfides

Basic and clinical studies suggest that hypothalamic-pituitary-adrenal (HPA) axis is the neuroendocrine-immune pathway that functionally regulates the chronic inflammatory disease including asthma. Our previous studies showed corresponding changes of cytokines and leukotriene B4 (LTB4) between brain and lung tissues in antigen-challenged asthmatic rats. Here, we investigated how the increased LTB4 level in brain interacts with HPA axis in regulating antigen-induced asthmatic response in sensitized rats.. Ovalbumin-sensitized rats were challenged by inhalation of antigen. Rats received vehicle, LTB4 or U75302 (a selective LTB4 BLT1 receptor inhibitor) was given via intracerebroventricular injection (i.c.v) 30 min before challenge. Lung resistance (RL) and dynamic lung compliance (Cdyn) were measured before and after antigen challenge. Inflammatory response in lung tissue was assessed 24 h after challenge. Expression of CRH mRNA and protein in hypothalamus were evaluated by RT-PCR and Western Blot, and plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were measured using the ELISA kits.. Antigen challenge decreased pulmonary function and induced airway inflammation, evoked HPA axis response in sensitized rats. Administration of LTB4 via i.c.v markedly attenuated airway contraction and inflammation. Meanwhile, LTB4 via i.c.v markedly increased CORT and ACTH level in plasma before antigen challenge, and followed by further increases in CORT and ACTH levels in plasma after antigen challenge in sensitized rats. Expression of CRH mRNA and protein in hypothalamus were also significantly increased by LTB4 via i.c.v in sensitized rats after antigen challenge. These effect were completely blocked by pre-treatment with BLT1 receptor antagonist U75302 (10 ng), but not by BLT2 antagonist LY255283.. LTB4 administered via i.c.v down-regulates the airway contraction response and inflammation through activation of the HPA axis via its BLT1 receptor. This study expands our concept of the regulatory role of intracranial inflammatory mediators in inflammatory diseases including asthma. The favourable effects of LTB4 on the HPA axis may help to explain the phenomenon of self-relief after an asthmatic attack.

Topics: Adrenocorticotropic Hormone; Airway Resistance; Animals; Asthma; Blotting, Western; Corticotropin-Releasing Hormone; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Fatty Alcohols; Female; Glycols; Hypothalamo-Hypophyseal System; Hypothalamus; Inflammation Mediators; Injections, Intraventricular; Leukotriene B4; Lung; Lung Compliance; Male; Ovalbumin; Pituitary-Adrenal System; Pulmonary Eosinophilia; Rats; Rats, Sprague-Dawley; Receptors, Leukotriene B4; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

To elucidate the ocular pharmacological properties of bepotastine besilate, a selective histamine H(1) receptor antagonist, when compared with other histamine H(1) receptor antagonists, using guinea pig allergic conjunctivitis models and in vitro models of eosinophil recruitment and mast cell membrane stabilization. Conjunctival vascular hyperpermeability was studied in guinea pigs passively sensitized with anti-ovalbumin antiserum or following subconjunctival injection of histamine. Modulation of eosinophil recruitment was evaluated for both platelet-activating factor (PAF)-induced eosinophil infiltration in guinea pigs and leukotriene B(4)-induced in vitro chemotaxis of guinea pig peritoneal eosinophils. Membrane-stabilizing effects of bepotastine also were studied with rat peritoneal mast cells stimulated with the ionophore A23187. Histamine H(1) receptor antagonists including bepotastine besilate were topically administered before ovalbumin, histamine or PAF challenges for in vivo experiments or were added directly to mast cell and eosinophil medium in vitro. Bepotastine besilate significantly inhibited conjunctival vascular hyperpermeability in a dose-dependent manner with maximal effect for bepotastine besilate 1.5%. In separate in vivo experiments, bepotastine besilate 1.0% was significantly more effective than levocabastine 0.025% in the passive sensitization model or olopatadine 0.1% in the histamine-induced hyperpermeability model. Bepotastine besilate 1.0% further suppressed PAF-induced eosinophil infiltration into conjunctival tissue more effectively than ketotifen 0.05%. Chemotaxis of guinea pig peritoneal eosinophils and histamine release from rat peritoneal mast cells in vitro were also inhibited by addition of bepotastine. Olopatadine had a weak effect as compared to that of bepotastine on eosinophil chemotaxis and no effect on mast cell histamine release in our study conditions. Bepotastine besilate was more potent than olopatadine, ketotifen, or levocabastine in reducing vascular hyperpermeability in various animal models of allergic conjunctivitis. Mast cell function and eosinophil chemotaxis were also inhibited in vitro with bepotastine, suggesting bepotastine acts as an inhibitor of allergic response through multiple mechanisms: histamine H(1) receptor antagonism, mast cell stabilization, and inhibition of eosinophil migration to ocular inflammatory sites.

Topics: Animals; Capillary Permeability; Cells, Cultured; Chemotaxis, Leukocyte; Conjunctiva; Conjunctivitis, Allergic; Disease Models, Animal; Dose-Response Relationship, Drug; Eosinophils; Guinea Pigs; Histamine; Histamine H1 Antagonists; Histamine Release; Leukotriene B4; Male; Mast Cells; Ovalbumin; Peritoneal Cavity; Piperidines; Platelet Activating Factor; Pyridines; Rats; Rats, Wistar

The authors investigated the role of leukotrienes (LTs) in the pathogenesis of silica-induced pulmonary fibrosis in mice during the progression from acute to chronic phases. Intratracheal instillation of silica particles induced progressive pulmonary fibrosis. The tissue content of cysteinyl (Cys) LTs and LTB(4) was markedly increased in the acute phase after silica instillation, concurrently with the up-regulation of LTB(4) receptor, transforming growth factor (TGF)-beta1, and tumor necrosis factor (TNF)-alpha, along with down-regulation of the CysLT type 2 receptor. Importantly, the tissue content of CysLTs and mRNA levels of TGF-beta1 and TNF-alpha were increased in the fibrotic lung in the chronic phase. Furthermore, strong immunohistochemical staining for the CysLT type 1 receptor, TNF-alpha, and TGF-beta1, but not for the CysLT type 2 receptor, was codetected in the pathological lesions during both acute and chronic phases. These findings suggest that an increase in LT production in the lung and modulation of homeostatic balance among LT receptors may contribute to the progression of pulmonary fibrosis.

Topics: Acute Disease; Animals; Bronchoalveolar Lavage Fluid; Cysteine; Disease Models, Animal; Disease Progression; Female; Hydroxyproline; Immunohistochemistry; Leukotriene B4; Leukotrienes; Lung; Mice; Mice, Inbred C57BL; Pulmonary Fibrosis; Receptors, Leukotriene; Receptors, Leukotriene B4; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Silicon Dioxide; Time Factors; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha

We evaluated the in vivo pharmacological properties of AM803 3-[3-tert-butylsulfanyl-1-[4-(6-ethoxy-pyridin-3-yl)-benzyl]-5-(5-methyl-pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid, a selective five-lipoxygenase-activating protein (FLAP) inhibitor, using rat and mouse models of acute inflammation. Oral administration of AM803 (1 mg/kg) resulted in sustained inhibition of ex vivo ionophore-challenged whole blood LTB4 biosynthesis with >90% inhibition for up to 12 h and an EC50 of approximately 7 nM. When rat lungs were challenged in vivo with calcium-ionophore, AM803 inhibited LTB4 and cysteinyl leukotriene (CysLT) production with ED50s of 0.12 mg/kg and 0.37 mg/kg, respectively. The inhibition measured 16 h following a single oral dose of 3 mg/kg was 86% and 41% for LTB4 and CysLTs, respectively. In an acute inflammation setting, AM803 dose-dependently reduced LTB4, CysLTs, plasma protein extravasation and neutrophil influx induced by peritoneal zymosan injection. Finally, AM803 increased survival time in mice exposed to a lethal intravenous injection of platelet activating factor (PAF). The magnitude of effect was similar to that of an inhibitor of five-lipoxygenase (5-LO) and LTA4 hydrolase but superior to a leukotriene CysLT1 receptor antagonist. In summary, AM803 is a novel, potent and selective FLAP inhibitor that has excellent pharmacodynamic properties in vivo and is effective in animal models of acute inflammation and in a model of lethal shock.

Topics: 5-Lipoxygenase-Activating Proteins; Animals; Carrier Proteins; Chronic Disease; Cysteine; Disease Models, Animal; Female; Humans; Indoles; Inflammation; Leukotriene B4; Leukotrienes; Lung; Male; Membrane Proteins; Mice; Pentanoic Acids; Platelet Activating Factor; Propionates; Rats; Substrate Specificity; Zymosan

Cyclooxygenase (COX) and 5-lipoxygenase (5-LOX), which play pivotal roles in atherogenesis, have been reported to be involved in plaque stability. Licofelone, a dual COX and 5-LOX inhibitor, has been reported to possess anti-atherogenic effect in rabbit atherosclerosis model. We therefore investigated the anti-atherogenic effect of BHB-TZD [5-(3,5-di-tert-butyl-4-hydroxybenzylidene)thiazolidin-2,4-dione], a dual COX and 5-LOX inhibitor, in low density lipoprotein receptor null (LDLR-/-) mice. Fifteen LDLR-/- mice were fed a western diet (control group), whereas 15 were fed a western diet plus 0.1% (w/w) BHB-TZD (BHB-TZD group). After 8 weeks, the BHB-TZD group had markedly lower serum levels of leukotriene B(4) and prostaglandin E(2) than the control group. Interestingly, BHB-TZD treatment also reduced plasma triglyceride level without significant changes in total cholesterol and HDL levels. Compared with control mice, BHB-TZD fed mice had 52% fewer fatty streak lesions in the aortic sinus, as well as fewer initial lesions in the aortic arch. Macrophage infiltration into the lesions was 40% lower, and collagen and smooth muscle cells were increased by 102% and 96%, respectively, in the BHB-TZD group compared with the control group. In addition, aortic expression of proatherogenic molecules including TNF-alpha, IL-1beta, IL-6, MCP-1 and VCAM-1, was lower in the BHB-TZD group than the control group. BHB-TZD treatment also reduced MMP-2 and MMP-9 expressions in aorta. In conclusion, BHB-TZD effectively attenuated atherosclerosis in mouse model, suggesting its therapeutic potential for atherosclerosis.

Topics: Animals; Aorta, Thoracic; Aortic Diseases; Arachidonate 5-Lipoxygenase; Atherosclerosis; Cholesterol; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Gene Expression Regulation; Hyperlipidemias; Inflammation Mediators; Leukotriene B4; Lipoproteins, HDL; Lipoxygenase Inhibitors; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocytes, Smooth Muscle; Prostaglandin-Endoperoxide Synthases; Receptors, LDL; RNA, Messenger; Thiazolidinediones; Time Factors; Triglycerides

A large and diverse array of chemoattractants control leukocyte trafficking, but how these apparently redundant signals collaborate in vivo is still largely unknown. We previously demonstrated an absolute requirement for the lipid chemoattractant leukotriene B(4) (LTB(4)) and its receptor BLT1 for neutrophil recruitment into the joint in autoantibody-induced arthritis. We now demonstrate that BLT1 is required for neutrophils to deliver IL-1 into the joint to initiate arthritis. IL-1-expressing neutrophils amplify arthritis through the production of neutrophil-active chemokines from synovial tissue cells. CCR1 and CXCR2, two neutrophil chemokine receptors, operate nonredundantly to sequentially control the later phase of neutrophil recruitment into the joint and mediate all neutrophil chemokine activity in the model. Thus, we have uncovered a complex sequential relationship involving unique contributions from the lipid mediator LTB(4), the cytokine IL-1, and CCR1 and CXCR2 chemokine ligands that are all absolutely required for effective neutrophil recruitment into the joint.

Topics: Animals; Arthritis; Cells, Cultured; Chemokines; Disease Models, Animal; Disease Susceptibility; Interleukin-1alpha; Interleukin-1beta; Leukotriene B4; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Receptors, CCR1; Receptors, Interleukin-8B; Receptors, Leukotriene; Synovial Fluid

Cochinchina momordica seed extract (SKMS10), which is composed of the major compounds momordica saponins, has been evaluated for its gastroprotective effects in rat models of acute gastric mucosal damage. Ethanol and water immersion restraint stress (WRS) induced gastric damage, including hemorrhages and edema, was significantly attenuated by pretreatment with SK-MS10. In addition, SK-MS10 reduced increases of mucosal myeloperoxidase (MPO), IL-1β, and TNFα levels and the expression of cPLA(2), and 5-LOX induced by ethanol or WRS. SK-MS10 also increased hexosamine, adherent mucus, and the expression of MUC5AC. Furthermore, SK-MS10 enhanced the mucosal expression of the CGRP gene and its serum levels.N(G)-methyl L-arginine (L-NMMA) or capsaicin desensitization reversed the SK-MS10-induced gastroprotection effect. These results suggest that SK-MS10 is a gastroprotective agent against acute gastric mucosal damage by suppressing proinflammatory cytokines, downregulating cPLA(2), 5-LOX, and increasing the synthesis of mucus. Furthermore, CGRP-NO pathway was found to play an important role in these gastroprotective effects of SK-MS10.

Topics: Animals; Arachidonate 5-Lipoxygenase; Calcitonin Gene-Related Peptide; Cyclooxygenase 2; Cytoprotection; Dinoprostone; Disease Models, Animal; Down-Regulation; Ethanol; Gastric Mucosa; Gastrointestinal Agents; Group IV Phospholipases A2; Hexosamines; Inflammation Mediators; Interleukin-1beta; Leukotriene B4; Male; Momordica; Mucin 5AC; Mucin-6; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Peroxidase; Plant Extracts; Rats; Rats, Sprague-Dawley; Restraint, Physical; RNA, Messenger; Seeds; Sensory Receptor Cells; Signal Transduction; Stomach Ulcer; Time Factors; Tumor Necrosis Factor-alpha

The lipid-derived inflammatory mediators leukotrienes (LTs) are produced during vascular injury. The aim of the present study was to determine the role of LT receptor signaling in the pathophysiology of in-stent stenosis.. New Zealand White rabbits were fed 0.3% cholesterol and subjected to angioplasty with balloon dilatation and stent implantation in the right carotid artery. Rabbits treated for 2 weeks with the BLT receptor antagonist BIIL284 (3 mg/kg once daily by oral gavage) displayed a significantly reduced in-stent intimal hyperplasia in carotid arteries compared with vehicle-treated rabbits. In addition, BIIL284 treatment significantly reduced the extracellular matrix metalloproteinase (MMP)-2 and MMP-9 activities in stented arteries. The inhibited MMP-9 activity was correlated with decreased macrophage content in the lesions. The LTB(4)-induced migration of vascular smooth muscle cells was significantly inhibited by transfection with siRNA against MMP-2. Finally, human arteries subjected to ex vivo angioplasty and stent implantation displayed an increased in-stent intimal hyperplasia and higher MMP-2 and -9 activities in the presence of LTB(4).. These results suggest a key role of LT signaling in the extracellular matrix degradation associated with hyperlipidemia and in-stent stenosis. In conclusion, targeting LT receptors may represent a therapeutic strategy in atherosclerosis and interventional cardiology.

Topics: Administration, Oral; Amidines; Angioplasty, Balloon; Animals; Carbamates; Carotid Artery, Common; Carotid Stenosis; Cell Line; Cell Movement; Cell Proliferation; Cholesterol, Dietary; Disease Models, Animal; Extracellular Matrix; Humans; Hyperplasia; Leukotriene Antagonists; Leukotriene B4; Macrophages; Male; Mammary Arteries; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Organ Culture Techniques; Rabbits; RNA Interference; RNA, Small Interfering; Secondary Prevention; Stents; Time Factors; Transfection

Compound ZLJ-6 [(Z)-1-methyl-1,5-dihydro-2-amino-5-[4-(mesyl)benzylidene]-4H-imi-dazole-4-one mesilate] is a potent inhibitor of cyclooxygenase (IC(50)=0.73 and 0.31 microM, for cyclooxygenase-1 and cyclooxygenase-2 respectively) in human whole blood. It also inhibited the production of thromboxane B(2) and prostaglandin E(2) in calcium ionophore A23187-induced human (IC(50)=0.50 microM) and rat whole blood (IC(50)=0.93 microM), and rat peritoneal leukocytes (IC(50)=2.27 microM). ZLJ-6 suppressed the activity of 5-lipoxygenase in the rat basophilic leukemia (RBL-1) cell lysate (IC(50)=0.32 microM) and in intact cells (IC(50)=1.06 microM) and reduced the generation of leukotriene B(4) (LTB(4)) in A23187-stimulated human (IC(50)=1.61 microM) or rat whole blood (IC(50)=0.99 microM), and rat peritoneal leukocytes (IC(50)=2.59 microM). In vivo, ZLJ-6, administered orally, demonstrated potent anti-inflammatory activity in the carrageenin-induced paw oedema model in rats and showed analgesic activity in the acetic acid-induced abdominal construction model in mice. No gastrointestinal ulcers were found with the anti-inflammatory dose (30 mg/kg) in normal rats. These results indicated that ZLJ-6 potently inhibited 5-lipoxygenase and cyclooxygenase, and blocked the production of LTB(4), TXB(2) and PGE(2). Thus ZLJ-6 is an ideal substitute for classical non-steroidal anti-inflammatory therapy.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents; Carrageenan; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Edema; Female; Humans; Imidazoles; Inhibitory Concentration 50; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Rats; Rats, Sprague-Dawley; Sulfones; Thromboxane B2

Understanding the neurobiology of pain in naturally occurring models of osteoarthritis (OA) may improve the understanding of human OA pain. Both COX and LOX have been associated with joint pain. This study evaluated COX-1, COX-2, and 5-LOX expression and activity in a naturally occurring canine model of secondary OA. Hip joint capsule with synovial tissue (HJC) and femoral head subchondral bone (FH) was collected from normal dogs and dogs undergoing total hip replacement for coxofemoral joint OA. Tissues were analyzed for COX-1, COX-2, and LOX protein, and PGE(2) and LTB(4). Significantly more COX-2 protein was present in OA HJC than normal joints (p = 0.0009). There was no significant difference in COX-1 or LOX protein, although LOX protein was increased (p = 0.069). PGE(2) concentration in normal and OA HJC was similar (p = 1.0). LTB(4) concentration in OA HJC was significantly greater than normal HJC (p = 0.028). Significantly more COX-1 (p = 0.0098), COX-2 (p = 0.0028), and LOX (p = 0.0095) protein was present in OA FH tissue compared to normal FH tissue. There were no differences in PGE(2) or LTB(4) concentration in normal and OA FH tissue (p = 0.77 and p = 0.11). Together, these data suggest both COX-2 and 5-LOX are appropriate targets for the management of pain associated with naturally occurring OA.

Topics: Animals; Arachidonate 5-Lipoxygenase; Arthroplasty, Replacement, Hip; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Dogs; Femur Head; Hip Joint; Leukotriene B4; Osteoarthritis, Hip; Synovial Membrane

Substance P (SP) is an important neuropeptide involved in neurogenic inflammation and most of its pathophysiological functions are mediated through binding to the neurokinin-1 receptor. SP exerts various proinflammatory actions on immune-cells, including macrophages. Several compounds such as cytokines have the capacity to activate and stimulate macrophages to produce arachidonic acid oxygenation and lipoxygenation products. Leukotriene B4 (LTB4) is one of the most important mediators of leukocyte activation in acute and chronic inflammatory reactions. LTB4 stimulates chemotaxis, lysosomal enzyme release, and cell aggregation. In this report, we studied the effect of SP on rat adherent granuloma macrophages (RAGMs). The chronic granuloma in rat was induced by dorsal injections of a potassium permanganate (KMnO4) saturated crystal solution (200 microl of a 1:40 dilution). After 7 days, all rats developed a subcutaneous granuloma in the injection site from which infiltrated macrophages were extracted, isolated, and cultured in vitro. We tested the hypothesis that SP stimulates the production of LTB4 in RAGMs and increases lipoxygenase expression. Here we show that the cell-free supernatant of RAGMs stimulated with SP (10 microM), resulted in statistically significant increases of LTB4 Preincubation of RAGMs with NDGA (nordihydroguaiaretic acid (10 microM), completely abolished the production of LTB(4) in the supernatants and lipoxygenase expression on RAGMs challenged with SP, or the cation ionophore A23187 (positive control). Similar effects were obtained when the cells were pretreated with dexamethasone (10 microM). Our results suggest that SP is able to stimulate the release of LTB4 and lipoxygenase expression in macrophages from chronic inflammatory granuloma and provide further evidence for a neuroinflammatory pathway.

Topics: Animals; Arachidonate 5-Lipoxygenase; Calcimycin; Dexamethasone; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Granuloma; Ionophores; Leukotriene B4; Lipoxygenase Inhibitors; Macrophages; Male; Masoprocol; Microscopy, Electron, Transmission; Potassium Permanganate; Radioimmunoassay; Rats; Rats, Wistar; Substance P; Time Factors; Up-Regulation

Statins have been proposed as a novel treatment of respiratory diseases. To determine the beneficial effects of statins on allergic bronchial asthma, the effect of systemic treatment with lovastatin on antigen-induced airway inflammation was investigated.. Male BALB/c mice were used.. Mice were sensitized and repeatedly challenged with ovalbumin (OA) antigen to induce asthmatic response. Animals were also treated with lovastatin (4 mg/kg/day, i.p.) once a day prior to and during the antigen inhalation period.. Inflammatory cell counts and levels of interleukin (IL)-4, IL-13, eotaxin, thymus and activation-regulated chemokine and leukotriene B(4) (LTB(4)) in bronchoalveolar lavage (BAL) fluids were measured.. Significant increases in eosinophils and levels of the T helper 2 cytokines, chemokines and LTB(4) in BAL fluids in association with the increments of total and OA-specific immunoglobulin E (IgE) in sera were observed in the repeatedly antigen-challenged mice. The airway eosinophilia was ameliorated by lovastatin, whereas it had no significant effect on the levels of these inflammatory mediators or IgE.. Lovastatin may be beneficial for the treatment of allergic inflammatory diseases in the airways, such as allergic bronchial asthma.

Topics: Animals; Anti-Inflammatory Agents; Antigens; Asthma; Bronchoalveolar Lavage Fluid; Cell Count; Cytokines; Disease Models, Animal; Eosinophilia; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Immunoglobulin E; Inflammation Mediators; Leukotriene B4; Lovastatin; Male; Mice; Mice, Inbred BALB C; Ovalbumin; Pneumonia

alpha-Humulene and trans-caryophyllene are plant sesquiterpenes with pronounced anti-inflammatory properties. Here, we evaluated the effects of these compounds in an experimental model of airways allergic inflammation.. Female BALB/c mice, sensitized to and challenged with ovalbumin received daily alpha-humulene or trans-caryophyllene (50 mg.kg(-1), orally) or alpha-humulene (1 mg.mL(-1), by aerosol) as either a preventive (for 22 days) or therapeutic (from the 18th to the 22nd day) treatment. Dexamethasone or budesonide was used as a positive control drug. Inflammation was determined on day 22 post-immunization by leukocyte recruitment, interleukin-5 (IL-5), CCL11, interferon-gamma (IFN-gamma) and leukotriene (LT)B(4) levels in bronchoalveolar lavage fluid (BALF). In addition, transcription factors [nuclear factor kappaB (NF-kappaB), activator protein 1 (AP-1)] and P-selectin in lung tissue were measured by immunohistochemistry and mucus secretion by histochemistry.. Preventive or therapeutic treatments with alpha-humulene, but not with trans-caryophyllene, significantly reduced the eosinophil recruitment to the BALF. In addition, alpha-humulene recovery INF-gamma and reduced the IL-5, CCL11 and LTB(4) levels in BALF, as well as the IL-5 production in mediastinal lymph nodes (in vitro assay). Furthermore, alpha-humulene decreased the NF-kB and the AP-1 activation, the expression of P-selectin and the increased mucus secretion in the lung.. alpha-Humulene, given either orally or by aerosol, exhibited marked anti-inflammatory properties in a murine model of airways allergic inflammation, an effect that seemed to be mediated via reduction of inflammatory mediators, adhesion molecule expression and transcription factors activation.

Topics: Administration, Oral; Aerosols; Animals; Anti-Inflammatory Agents; Bronchoalveolar Lavage Fluid; Chemokine CCL11; Disease Models, Animal; Drug Evaluation, Preclinical; Eosinophils; Female; Immunohistochemistry; Interferon-gamma; Interleukin-5; Leukotriene B4; Lung; Mice; Mice, Inbred BALB C; Monocyclic Sesquiterpenes; Monocytes; Neutrophils; NF-kappa B; Ovalbumin; Respiratory Hypersensitivity; Sesquiterpenes; Transcription Factor AP-1

Although the chemokines monocyte chemoattractant protein-1 (Ccl2/JE/MCP-1) and macrophage inflammatory protein-1alpha (Ccl3/MIP-1alpha) have recently been implicated in neutrophil migration, the underlying mechanisms remain largely unclear.. Stimulation of the mouse cremaster muscle with Ccl2/JE/MCP-1 or Ccl3/MIP-1alpha induced a significant increase in numbers of firmly adherent and transmigrated leukocytes (>70% neutrophils) as observed by in vivo microscopy. This increase was significantly attenuated in mice receiving an inhibitor of RNA transcription (actinomycin D) or antagonists of platelet activating factor (PAF; BN 52021) and leukotrienes (MK-886; AA-861). In contrast, leukocyte responses elicited by PAF and leukotriene-B(4) (LTB(4)) themselves were not affected by actinomycin D, BN 52021, MK-886, or AA-861. Conversely, PAF and LTB(4), but not Ccl2/JE/MCP-1 and Ccl3/MIP-1alpha, directly activated neutrophils as indicated by shedding of CD62L and marked upregulation of CD11b. Moreover, Ccl2/JE/MCP-1- and Ccl3/MIP-1alpha-elicited leakage of fluorescein isothiocyanate dextran as well as collagen IV remodeling within the venular basement membrane were completely absent in neutrophil-depleted mice.. Ccl2/JE/MCP-1 and Ccl3/MIP-1alpha mediate firm adherence and (subsequent) transmigration of neutrophils via protein synthesis and secondary generation of leukotrienes and PAF, which in turn directly activate neutrophils. Thereby, neutrophils facilitate basement membrane remodeling and promote microvascular leakage.

Topics: 1-Alkyl-2-acetylglycerophosphocholine Esterase; Animals; Benzoquinones; Cells, Cultured; Chemokine CCL2; Chemokine CCL3; Chemotaxis, Leukocyte; Dactinomycin; Disease Models, Animal; Indoles; Indomethacin; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Protein Biosynthesis; Random Allocation; Sensitivity and Specificity

Leukotrienes (LTs) are proinflammatory lipid mediators synthesized by the conversion of arachidonic acid (AA) to LTA(4) by the enzyme 5-lipoxygenase (5-LO) in the presence of 5-LO-activating protein (FLAP). 3-[3-tert-Butylsulfanyl-1-[4-(6-methoxy-pyridin-3-yl)-benzyl]-5-(pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid (AM103) is a novel selective FLAP inhibitor in development for the treatment of respiratory conditions such as asthma. In a rat ex vivo whole-blood calcium ionophore-induced LTB(4) assay, AM103 (administered orally at 1 mg/kg) displayed >50% inhibition for up to 6 h with a calculated EC(50) of approximately 60 nM. When rat lung was challenged in vivo with calcium ionophore, AM103 inhibited LTB(4) and cysteinyl leukotriene (CysLT) production with ED(50) values of 0.8 and 1 mg/kg, respectively. In this model, the EC(50) derived from plasma AM103 was approximately 330 nM for inhibition of both LTB(4) and CysLT. In an acute inflammation setting, AM103 displayed dose-dependent inhibition of LTB(4), CysLT, and plasma protein extravasation induced by peritoneal zymosan injection. In a model of chronic lung inflammation using ovalbumin-primed and challenged BALB/c mice, AM103 reduced the concentrations of eosinophil peroxidase, CysLTs, and interleukin-5 in the bronchoalveolar lavage fluid. Finally, AM103 increased survival time in mice exposed to a lethal intravenous injection of platelet-activating factor. In summary, AM103 is a novel, potent and selective FLAP inhibitor that has excellent pharmacodynamic properties in vivo and is effective in animal models of acute and chronic inflammation and in a model of lethal shock.

Topics: 5-Lipoxygenase-Activating Proteins; Acute Disease; Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Asthma; Carrier Proteins; Chronic Disease; Disease Models, Animal; Dose-Response Relationship, Drug; Extravasation of Diagnostic and Therapeutic Materials; Female; Humans; Indoles; Inflammation; Leukotriene B4; Male; Membrane Proteins; Mice; Mice, Inbred BALB C; Pneumonia; Propionates; Rats; Rats, Sprague-Dawley; Zymosan

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 explore the effects and the mechanism of Wuwei Dilong Decoction (Schisandra Fruit and Earthworm Decoction) for treatment of asthma.. The asthma guinea pig model was established with spray of ovalbumin (OVA). Fifteen days later, the guinea pigs were administered by intra-gastric perfusion of Wuwei Dilong Decoction once a day for 8 consecutive days. Blood samples were taken for testing the total leucocytes, eosinophil (EOS), lymphocytes, interferon-gamma (IFN-gamma) and leukotriene B4 (LTB4).. In the asthma model group, the total leucocytes, EOS and lymphocytes were all increased, with significant differences as compared with the different dosage Wuwei Dilong Decoction groups (P < 0.01 or P < 0.05). The serum LTB4 in the asthma model group was significantly increased and IFN-gamma decreased. After administration of Wuwei Dilong Decoction of the large, medium and small dosages, LTB4 decreased, while IFN-gamma increased (P < 0.05 or P < 0.01).. Wuwei Dilong Decoction can inhibit infiltration and diffusion of the inflammatory cells in the asthma model guinea pigs, and regulate LTB4 and IFN-gamma, which is probably one of the important mechanisms of Wuwei Dilong Decoction for relieving asthma.

Topics: Analysis of Variance; Animals; Asthma; Disease Models, Animal; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Enzyme-Linked Immunosorbent Assay; Eosinophils; Guinea Pigs; Interferon-gamma; Leukocyte Count; Leukocytes; Leukotriene B4; Lymphocytes; Medicine, Chinese Traditional; Random Allocation; Treatment Outcome

Aberrant arachidonic acid metabolism, especially altered cyclooxygenase and 5-lipoxygenase (LOX) activities, has been associated with chronic inflammation as well as carcinogenesis in human oral cavity tissues. Here, we examined the effect of Zyflamend, a product containing 10 concentrated herbal extracts, on development of 7,12-dimethylbenz[alpha]anthracene (DMBA)-induced inflammation and oral squamous cell carcinoma (SCC). A hamster cheek pouch model was used in which 0.5% DMBA was applied topically onto the left cheek pouch of male Syrian golden hamsters either three times per week for 3 weeks (short term) or 6 weeks (long term). Zyflamend was then applied topically at one of three different doses (25, 50 and 100 microl) onto the left cheek pouch three times for 1 week (short-term study) or chronically for 18 weeks. Zyflamend significantly reduced infiltration of inflammatory cells, incidence of hyperplasia and dysplastic lesions, bromodeoxyuridine-labeling index as well as number of SCC in a concentration-dependent manner. Application of Zyflamend (100 microl) reduced formation of leukotriene B(4) (LTB(4)) by 50% compared with DMBA-treated tissues. The reduction of LTB(4) was concentration dependent. The effect of Zyflamend on inhibition of LTB(4) formation was further confirmed with in vitro cell-based assay. Adding LTB(4) to RBL-1 cells, a rat leukemia cell line expressing high levels of 5-LOX and LTA(4) hydrolase, partially blocked antiproliferative effect of Zyflamend. This study demonstrates that Zyflamend inhibited LTB(4) formation and modulated adverse histopathological changes in the DMBA-induced hamster cheek pouch model. The study suggests that Zyflamend might prevent oral carcinogenesis at the post-initiation stage.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Anticarcinogenic Agents; Carcinogens; Cell Line, Tumor; Cell Proliferation; Cricetinae; Disease Models, Animal; Leukotriene B4; Mouth Neoplasms; Plant Extracts; Rats

Acute lung injury (ALI) and its most severe form, the acute respiratory distress syndrome (ARDS) are frequent complications in critically ill patients and are responsible for significant morbidity and mortality. So far, experimental evidence supports the role of oxidants and oxidative injury in the pathogenesis of ALI/ARDS. In this study, the antioxidant effects of conventional N-acetylcysteine (NAC) and liposomally entrapped N-acetylcysteine (L-NAC) were evaluated in experimental animals challenged with lipopolysaccharide (LPS). Rats were pretreated with empty liposomes, NAC, or L-NAC (25mg/kg body weight, iv); 4h later were challenged with LPS (E. coli, LPS 0111:B4) and sacrificed 20h later. Challenge of saline (SAL)-pretreated animals with LPS resulted in lung injury as evidenced by increases in wet lung weight (edema), increases in lipid peroxidation (marker of oxidative stress), decreases of lung angiotensin-converting enzyme (ACE) (injury marker for pulmonary endothelial cells) and increases in the pro-inflammatory eicosanoids, thromboxane B(2) and leukotriene B(4). The LPS challenge also increased pulmonary myeloperoxidase activity and chloramine concentrations indicative of neutrophil infiltration and activation of the inflammatory response. Pretreatment of animals with L-NAC resulted in significant increases in the levels of non-protein thiols and NAC levels in lung homogenates (p<0.05) and bronchoalveolar lavage fluids (p<0.001), respectively. L-NAC was significantly (p<0.05) more effective than NAC or empty liposomes in attenuating the LPS-induced lung injuries as indicated by the aforementioned injury markers. Our results suggested that the delivery of NAC as a liposomal formulation improved its prophylactic effectiveness against LPS-induced lung injuries.

Topics: Acetylcysteine; Acute Lung Injury; Animals; Antioxidants; Bronchoalveolar Lavage Fluid; Chemistry, Pharmaceutical; Chloramines; Disease Models, Animal; Drug Compounding; Injections, Intravenous; Leukotriene B4; Lipid Peroxidation; Lipopolysaccharides; Liposomes; Lung; Male; Organ Size; Peptidyl-Dipeptidase A; Peroxidase; Rats; Rats, Sprague-Dawley; Sulfhydryl Compounds; Thromboxane B2; Tumor Necrosis Factor-alpha

Cytosolic phospholipase A2alpha (cPLA2) plays an important role in the development of several inflammatory diseases. The aim of the present study is to determine whether inhibition of cPLA2 expression, using specific antisense oligonucleotides against cPLA2 (antisense), is efficient in reducing inflammation after its development. Two mouse models of inflammation were included in the study: thioglicolate peritonitis and collagen-induced arthritis (CIA). The antisense was found to be specific and efficient in inhibiting cPLA2 expression and NADPH oxidase activity ex vivo in peritoneal phagocytes. Immunoblotting and immunohistochemistry analysis showed a significant elevation in cPLA2 expression in the inflamed joints of collagen-induced arthritis mice localized in cell infiltrate, chondrocytes and the surrounding skin and skeletal muscle. Similarly, the cPLA2 metabolite, leukotriene B4, accumulated in the peritoneal cavity of mice with peritonitis. Inhibition of elevated cPLA2 expression after development of inflammation by intravenous administration of antisense resulted in a dramatic reduction in inflammation and a significant reduction in neutrophils recruitment to the site of inflammation in both mouse models of inflammation. Our results demonstrate the critical role of cPLA2 for the duration of inflammation and suggest that inhibition of cPLA2 expression by antisense oligonucleotides may serve as an efficient treatment of inflammatory diseases.

Topics: Animals; Arthritis, Experimental; Collagen Type II; Disease Models, Animal; Group IV Phospholipases A2; Leukotriene B4; Mice; Mice, Inbred DBA; Neutrophil Infiltration; Neutrophils; Oligonucleotides, Antisense; Peritonitis; Superoxides; Thioglycolates

The trafficking of immune cells to inflamed joints is the hallmark of rheumatoid arthritis. It has been known for years that neutrophils are abundant in the rheumatoid joints and have the potential to inflict tissue damage by the secretion of oxidants and proteases; however, the crucial role of neutrophil trafficking to the joints has only been demonstrated in recent years using transgenic mice and animal models of the disease. This finding opens the door to potential therapies based on inhibition of neutrophil trafficking. In this issue of the European Journal of Immunology, a study reports the use of antisense RNA to knock down the expression of cytosolic phospholipase A2alpha in mice. This has a major effect on neutrophil trafficking into inflamed joints and reverses the inflammatory swelling and tissue damage in the animal model used. This puts cytosolic phospholipase A2alpha, alongside its product leukotriene B4, on the list of potential targets for reducing cell trafficking to the joint in chronic inflammatory diseases like rheumatoid arthritis.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cell Movement; Disease Models, Animal; Group IV Phospholipases A2; Joints; Leukotriene B4; Mice; Neutrophil Infiltration; Neutrophils; RNA, Antisense

Leukotriene B4 (LTB4) mediates different inflammatory events such as neutrophil migration and pain. The present study addressed the mechanisms of LTB4-mediated joint inflammation-induced hypernociception. It was observed that zymosan-induced articular hypernociception and neutrophil migration were reduced dose-dependently by the pretreatment with MK886 (1-9 mg/kg; LT synthesis inhibitor) as well as in 5-lypoxygenase-deficient mice (5LO(-/-)) or by the selective antagonist of the LTB(4) receptor (CP105696; 3 mg/kg). Histological analysis showed reduced zymosan-induced articular inflammatory damage in 5LO(-/-) mice. The hypernociceptive role of LTB4 was confirmed further by the demonstration that joint injection of LTB4 induces a dose (8.3, 25, and 75 ng)-dependent articular hypernociception. Furthermore, zymosan induced an increase in joint LTB4 production. Investigating the mechanism underlying LTB4 mediation of zymosan-induced hypernociception, LTB4-induced hypernociception was reduced by indomethacin (5 mg/kg), MK886 (3 mg/kg), celecoxib (10 mg/kg), antineutrophil antibody (100 mug, two doses), and fucoidan (20 mg/kg) treatments as well as in 5LO(-/-) mice. The production of LTB4 induced by zymosan in the joint was reduced by the pretreatment with fucoidan or antineutrophil antibody as well as the production of PGE2 induced by LTB4. Therefore, besides reinforcing the role of endogenous LTB4 as an important mediator of inflamed joint hypernociception, these results also suggested that the mechanism of LTB4-induced articular hypernociception depends on prostanoid and neutrophil recruitment. Furthermore, the results also demonstrated clearly that LTB4-induced hypernociception depends on the additional release of endogenous LTs. Concluding, targeting LTB4 synthesis/action might constitute useful therapeutic approaches to inhibit articular inflammatory hypernociception.

Topics: Animals; Arachidonate 5-Lipoxygenase; Benzopyrans; Carboxylic Acids; Cell Movement; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Indoles; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Temporomandibular Joint; Temporomandibular Joint Disorders; Time Factors; Zymosan

We investigated the effect of intrauterine undernourishment on some features of asthma using a model of allergic lung inflammation in rats. The effects of age at which the rats were challenged (5 and 9 wk) were also evaluated.. Intrauterine undernourished offspring were obtained from dams that were fed 50% of the nourished diet of counterparts and were immunized at 5 and 9 wk of age. They were tested for immunoglobulin E anti-ova titers (by passive cutaneous anaphylaxis), cell count in the bronchoalveolar fluid, leukotriene concentration, airway reactivity, mucus production, and blood corticosterone and leptin concentrations 21 d after immunologic challenge.. Intrauterine undernourishment significantly reduced the antigen-specific immunoglobulin E production, inflammatory cell infiltration into airways, mucus secretion, and production of leukotrienes B(4)/C(4) in the lungs in both age groups compared with respective nourished rats. The increased reactivity to methacholine that follows antigen challenge was not affected by intrauterine undernourishment. Corticosterone levels increased with age in the undernourished rats' offspring, but not in the nourished rats' offspring. Undernourished offspring already presented high levels of corticosterone before inflammatory stimulus and were not modified by antigen challenge. Leptin levels increased with challenge in the nourished rats but not in the undernourished rats and could not be related to corticosterone levels in the undernourished rats.. Intrauterine undernourishment has a striking and age-dependent effect on the offspring, reducing lung allergic inflammation.

Topics: Age Factors; Animals; Bronchoalveolar Lavage Fluid; Corticosterone; Disease Models, Animal; Female; Fetal Diseases; Immunoglobulin E; Immunohistochemistry; Leptin; Leukocytes; Leukotriene B4; Male; Malnutrition; Pregnancy; Prenatal Exposure Delayed Effects; Prenatal Nutritional Physiological Phenomena; Random Allocation; Rats; Rats, Wistar

Although acute lung injury (ALI) is an important problem in humans, its pathogenesis is poorly understood. Airway instillation of bacterial LPS, a known complement activator, represents a frequently used model of ALI. In the present study, pathways in the immunopathogenesis of ALI were evaluated. ALI was induced in wild-type, C3(-/-), and C5(-/-) mice by airway deposition of LPS. To assess the relevant inflammatory mediators, bronchoalveolar lavage fluids were evaluated by ELISA analyses and various neutralizing Abs and receptor antagonists were administered in vivo. LPS-induced ALI was neutrophil-dependent, but it was not associated with generation of C5a in the lung and was independent of C3, C5, or C5a. Instead, LPS injury was associated with robust generation of macrophage migration inhibitory factor (MIF), leukotriene B(4) (LTB4), and high mobility group box 1 protein (HMGB1) and required engagement of receptors for both MIF and LTB4. Neutralization of MIF or blockade of the MIF receptor and/or LTB4 receptor resulted in protection from LPS-induced ALI. These findings indicate that the MIF and LTB4 mediator pathways are involved in the immunopathogenesis of LPS-induced experimental ALI. Most strikingly, complement activation does not contribute to the development of ALI in the LPS model.

Topics: Animals; Bronchoalveolar Lavage Fluid; Complement Activation; Complement System Proteins; Disease Models, Animal; HMGB1 Protein; Inflammation Mediators; Leukotriene B4; Lipopolysaccharides; Lung; Macrophage Migration-Inhibitory Factors; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Respiratory Distress Syndrome

Licofelone, a dual anti-inflammatory drug that inhibits 5-lipoxygenase (LOX) and cyclooxygenase (COX) enzymes, may have a better cardiovascular profile that cycloxygenase-2 inhibitors due to cycloxygenase-1 blockade-mediated antithrombotic effect and a better gastrointestinal tolerability. We examined the anti-inflammatory effect of licofelone on atherosclerotic lesions as well as in isolated neutrophils from whole blood of rabbits compared with a selective inhibitor of COX-2, rofecoxib. We also assessed the antithrombotic effect of licofelone in rabbit platelet-rich plasma. For this purpose, 30 rabbits underwent injury of femoral arteries, and they were randomized to receive 10 mg/kg/day licofelone or 5 mg/kg/day rofecoxib or no treatment during 4 weeks with atherogenic diet in all cases. Ten healthy rabbits were used as controls. Neutrophils and platelets were isolated from peripheral blood of rabbits for ex vivo studies. Licofelone reduced intima/media ratio in injured arteries, the macrophages infiltration in the neointimal area, monocyte chemoattractant protein-1 (MCP-1) gene expression, and the activation of nuclear factor-kappaB in rabbit atheroma. Moreover, licofelone inhibited COX-2 and 5-LOX protein expression in vascular lesions. Rofecoxib only diminished COX-2 protein expression and MCP-1 gene expression in vascular atheroma. Prostaglandin E(2) in rabbit plasma was attenuated by both drugs. Licofelone almost abolished 5-LOX activity by inhibiting leukotriene B4 generation in rabbit neutrophils and prevented platelet thromboxane B2 production from whole blood. Licofelone reduces neointimal formation and inflammation in an atherosclerotic rabbit model more markedly than rofecoxib. This effect, together with the antiplatelet activity of licofelone, suggests that this drug may have a favorable cardiovascular profile.

Topics: Acetates; Animals; Atherosclerosis; Chemokine CCL2; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Leukotriene B4; Lipids; Lipoxygenase Inhibitors; Macrophages; Male; NF-kappa B; Pyrroles; Rabbits; RNA, Messenger; Thromboxane B2; Tunica Intima

The study was to evaluate the effect of triterpene acids of Eriobotrya japonica (thunb.) lindl. leaf (TAL) on inflammatory cytokine and mediator expression in alveolar macrophages (AM) of chronic bronchitic (CB) rats.. CB was induced by endotracheal instillation of lipopolysaccharide (LPS) followed by Bacillus Calmette Guerin (BCG) injection via the caudal vein one week later. Treatment groups received TAL at there different doses (50, 150, or 450 mg/kg daily i. g.), Ketotifen fumarate (5 mg/kg daily i. g.) or dexamethasone (1.2 mg/kg daily i. g.) for two weeks, 7 days after LPS injection. AM were then isolated and incubated for 24 h. IL-1, TNF-alpha and PGE2 levels in cultured supernatants were measured by thymocyte co-stimulating assay and radioimmunoassay. Immunocytochemistry staining and western-blot were used for intracellular location and activation of p65 subunit of NF-kB. LTB(4) level was analyzed by reverse-phase high performance liquid chromatography (RP-HPLC).. The levels of TNF-alpha, IL-1, NF-kB, PGE2 and LTB(4) expression in AM of TAL groups were significantly decreased compared to the CB group (P < 0.05 or P < 0.01), in a dose dependent manner.. TAL inhibited NF-kB activation in AM from CB rats and led to down regulation of TNF-alpha, IL-1, PGE(2) and LTB(4) expression, which might be a mechanism for its anti-inflammatory effects in CB rats.

Topics: Animals; Bronchitis, Chronic; Cell Nucleus; Cells, Cultured; Cytokines; Cytoplasm; Dinoprostone; Disease Models, Animal; Eriobotrya; Immunohistochemistry; Leukotriene B4; Macrophages, Alveolar; Male; Molecular Structure; NF-kappa B; Plant Extracts; Plant Leaves; Protein Subunits; Rats; Rats, Sprague-Dawley; Triterpenes; Ursolic Acid

A series of arylacetic acid derivatives bearing methyl(arylethyl)amino groups were prepared and their antileukotrienic activities involving LTB(4) were evaluated. Regression analysis has shown a strong dependence of these activities on lipophilicity for both LTB(4) receptor binding and inhibition of LTB(4) biosynthesis; parabolic relationships were derived. The values of slopes of the ascending linear parts of these dependences indicate various types of hydrophobic binding at the site of ligand interaction with relevant biomacromolecules. The anti-inflammatory effect of the compounds under study was also evaluated in three animal models of inflammation and their possible utilization in the treatment of ulcerative colitis (UC) was followed. The importance of antileukotrienic activities for the anti-inflammatory effect, especially in the model of UC was discussed, but further experiments are necessary to confirm the respective relations.

Topics: Acetamides; Animals; Colitis, Ulcerative; Disease Models, Animal; Edema; Hydrophobic and Hydrophilic Interactions; Leukotriene B4; Neutrophils; Rats; Receptors, Leukotriene B4; Structure-Activity Relationship

Leukotriene B(4) is a proinflammatory lipid mediator generated by the enzymes 5-lipoxygenase and leukotriene A(4) hydrolase. Leukotriene B(4) signals primarily through its high-affinity G protein-coupled receptor, BLT1, which is highly expressed on specific leukocyte subsets. Recent genetic studies in humans as well as knockout studies in mice have implicated the leukotriene synthesis pathway in several vascular pathologies. In this study, we tested the hypothesis that BLT1 is necessary for abdominal aortic aneurysm (AAA) formation, a major complication of atherosclerotic vascular disease. Chow-fed Apoe(-/-) and Apoe(-/-)/Blt1(-/-) mice were treated with a 4-wk infusion of angiotensin II (1000 ng/min/kg) beginning at 20 wk of age, in a well-established murine AAA model. We found a reduced incidence of AAA formation as well as concordant reductions in the maximum suprarenal/infrarenal diameter and total suprarenal/infrarenal area in the angiotensin II-treated Apoe(-/-)/Blt1(-/-) mice as compared with the Apoe(-/-) controls. Diminished AAA formation in BLT1-deficient mice was associated with significant reductions in mononuclear cell chemoattractants and leukocyte accumulation in the vessel wall, as well as striking reductions in the production of matrix metalloproteinases-2 and -9. Thus, we have shown that BLT1 contributes to the frequency and size of abdominal aortic aneurysms in mice and that BLT1 deletion in turn inhibits proinflammatory circuits and enzymes that modulate vessel wall integrity. These findings extend the role of BLT1 to a critical complication of vascular disease and underscore its potential as a target for intervention in modulating multiple pathologies related to atherosclerosis.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Cell Migration Inhibition; Disease Models, Animal; Humans; Leukotriene B4; Macrophages; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Mice; Mice, Inbred C57BL; Mice, Knockout; Monocytes; Receptors, Leukotriene B4; T-Lymphocytes

UR-1505 is a novel pentafluoropropoxy derivative of salicylic acid, selected from a series of salicylate derivatives, according to their activity as inhibitors of T-lymphocyte activation. This study describes the anti-inflammatory activity of UR-1505 on trinitrobenzenesulphonic acid-induced colitis in rat, an experimental model that resembles to Crohn's disease (CD), as well as its in vitro effects on T-cells and bone marrow-derived macrophages (BMDM) activation. UR-1505 showed intestinal anti-inflammatory effect, associated with reduced colonic levels of TNFalpha and LTB(4), inhibition of the expression of IFNgamma and iNOS, and lower colonic leukocyte infiltration. The in vitro assays revealed that UR-1505 also inhibited T-lymphocyte proliferation and IL-12/IFNgamma production, two of the main pro-inflammatory cytokines involved in the pathogenesis of CD. However, UR-1505 did not modify LPS- nor IFNgamma-induced activation in BMDM. Thus, UR-1505 specifically affects T-cells without modifying the activation of BMDM. In conclusion, the intestinal anti-inflammatory activity of UR-1505 seems to be mediated by a reduction in the recruitment of immune cells to the inflammatory foci, together with the inhibition of T-cell activation. These results suggest that UR-1505 may be an interesting candidate to be explored for the treatment of CD.

Topics: Animals; Anti-Inflammatory Agents; Cells, Cultured; Colitis; Colon; Crohn Disease; Disease Models, Animal; Female; Glutathione; Interferon-gamma; Leukotriene B4; Macrophages; Mice; Mice, Inbred BALB C; Nitric Oxide Synthase Type II; Rats; Rats, Wistar; Salicylates; Spleen; T-Lymphocytes; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha

To study the mechanism involved in the potentially beneficial effect of ultra low dose aspirin (ULDA) in prehepatic portal hypertension, rats were pretreated with selective COX 1 or 2 inhibitors (SC-560 or NS-398 respectively), and subsequently injected with ULDA or placebo.. Portal hypertension was induced by portal vein ligation. Platelet activity was investigated with an in-vivo model of laser induced thrombus production in mesenteric circulation and induced hemorrhagic time (IHT). Platelet aggregation induced by ADP and dosing of prostanoid products 6-keto-PGF1alpha, TXB2, PGE2 and LTB4 were also performed.. The portal hypertensive group receiving a placebo showed a decreased in vivo platelet activity with prolonged IHT, an effect that was normalized by ULDA. SC-560 induced a mild antithrombotic effect in the normal rats, and an unmodified effect of ULDA. NS-398 had a mild prothrombotic action in portal hypertensive rats, similar to ULDA, but inhibited a further effect when ULDA was added. An increased 6-keto-PGF1alpha was observed in portal hypertensive group that was normalised after ULDA administration. TXA2 level after ULDA, remained unchanged.. These results suggest that the effect of ULDA on platelet activity in portal hypertensive rats, could act through a COX 2 pathway more than the COX 1, predominant for aspirin at higher doses.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Aspirin; Blood Platelets; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Hypertension, Portal; Lasers; Leukotriene B4; Male; Nitrobenzenes; Platelet Activation; Pyrazoles; Rats; Rats, Wistar; Sulfonamides; Thrombosis; Thromboxane B2

Resolvin E1 (RvE1) is a potent proresolving mediator of inflammation derived from omega-3 eicosapentaenoic acid that acts locally to stop leukocyte recruitment and promote resolution. RvE1 displays potent counter-regulatory and tissue-protective actions in vitro and in vivo. Periodontal disease is a local inflammatory disease initiated by bacteria characterized by neutrophil-mediated tissue injury followed by development of a chronic immune lesion. In this study, we report the treatment of established periodontitis using RvE1 as a monotherapy in rabbits compared with structurally related lipids PGE(2) and leukotriene B(4). PGE(2) and leukotriene B(4) each enhanced development of periodontitis and worsened the severity of disease. Promotion of resolution of inflammation as a therapeutic target with RvE1 resulted in complete restoration of the local lesion, and reduction in the systemic inflammatory markers C-reactive protein and IL-1beta. This report is the first to show that resolution of inflammation by a naturally occurring endogenous lipid mediator results in complete regeneration of pathologically lost tissues, including bone.

Topics: Alveolar Bone Loss; Animals; C-Reactive Protein; Chronic Disease; Dinoprostone; Disease Models, Animal; Eicosapentaenoic Acid; Homeostasis; Inflammation; Inflammation Mediators; Interleukin-1beta; Leukotriene B4; Neutrophil Infiltration; Neutrophils; Periodontitis; Rabbits

The effect of smoke-dried bonito undigested fraction remaining after microbial protease treatment (SDBR) on a spontaneously occurring mouse model of atopic dermatitis was studied in male 5-wk-old, NC/Nga mice. Smoke-dried bonito, Katsuobushi, is a traditional Japanese food. SDBR contains 2 major components: bonito oil and protease-undigested proteins. Mice were fed a casein diet containing corn oil (C diet) or a diet containing SDBR (SDBR diet) for 18 wk. In comparison with the C diet, the SDBR diet alleviated the increase in skin severity score and plasma IgE concentration in a time-dependent manner, and lowered leucotriene B(4) (LTB(4))-releasing ability upon calcium ionophore A23187 stimulation. The SDBR diet did not affect scratching time. These results demonstrate that SDBR diet alleviates atopic dermatitis-like skin lesions in NC/Nga mice.

Topics: Animals; Behavior, Animal; Body Weight; Caseins; Corn Oil; Dehydration; Dermatitis, Atopic; Disease Models, Animal; Fish Oils; Fishes; Food Preservation; Immunoglobulin E; Leukotriene B4; Male; Mice; Mice, Inbred Strains; Peptide Hydrolases; Severity of Illness Index; Time Factors

Inflammatory bowel disease is associated with intestinal oxidative stress. In the present study we test the preventative effect of Lactobacillus fermentum, a probiotic that produces per se glutathione, in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis.. Colitis was induced in rats by intracolonic administration of 10 mg of TNBS dissolved in 0.25 ml of 50% ethanol. L. fermentum was administered orally (5x10(8) CFU suspended in 0.5 ml of skim milk) to a group of rats for 3 weeks, starting 2 weeks before colitis induction. Colonic damage was evaluated both histologically and biochemically, and the colonic luminal contents were used for bacterial studies as well as for short chain fatty acid (SCFA) production.. L. fermentum treatment resulted in an amelioration of the inflammatory response in colitic rats as evidenced histologically and by a significant reduction of colonic MPO activity (P<0.05). The probiotic partially counteracted the colonic glutathione depletion induced by the inflammatory process. In addition, probiotic-treated colitic rats showed significant lower colonic tumour necrosis factor (TNF)alpha levels (P<0.01) and inducible nitric oxide synthase (iNOS) expression when compared to non-treated rats. Finally, the probiotic induced growth of Lactobacilli species and production of SCFA in colonic contents in comparison with control colitic rats.. Administration of the probiotic L. fermentum facilitates the recovery of the inflamed tissue in the TNBS model of rat colitis, an effect associated with increased levels of glutathione as well as with amelioration of the production of some of the mediators involved in the inflammatory response of the intestine, such as TNFalpha and NO.

Topics: Analysis of Variance; Animals; Colitis; Colony Count, Microbial; Disease Models, Animal; Fatty Acids, Volatile; Female; Glutathione; Inflammation Mediators; Intestinal Mucosa; Leukotriene B4; Limosilactobacillus fermentum; Neutrophil Infiltration; Nitric Oxide Synthase Type II; Oxidative Stress; Peroxidase; Probiotics; Rats; Rats, Wistar; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha

Leptin is an adipocyte-derived hormone that declines dramatically during fasting and plays a pivotal role in the neuroendocrine response to starvation. Previously, we employed leptin-deficient (ob/ob) mice to identify an important role for leptin in the host defense against Klebsiella pneumonia.. To assess the effects of fasting on the innate immune response against pneumococcal pneumonia and to determine the effects of maintaining circulating leptin levels on host defense in fasted mice.. C57BL/6 mice were either fed ad libitum or fasted for 48 h and given an intraperitoneal injection of saline or recombinant leptin (1 microg/g of body weight) twice daily for 48 h before bacterial challenge. Mice were challenged with 10(5) cfu of Streptococcus pneumoniae via the intranasal route.. Lung homogenate S. pneumoniae burden was nearly 20-fold greater in the fasted as compared with fed mice. The impairment in bacterial clearance observed in fasted animals was associated with reduced bronchoalveolar lavage neutrophil counts and interleukin-6 and macrophage inflammatory protein-2 levels. Alveolar macrophages from fasted animals also exhibited defective phagocytosis and killing of S. pneumoniae and reduced calcium-ionophore-stimulated leukotriene B(4) synthesis in vitro. In contrast, the provision of exogenous leptin to fasted animals restored bacterial clearance, bronchoalveolar lavage levels of neutrophils and cytokines, alveolar macrophage bacterial killing, and leukotriene B(4) synthesis.. These results suggest that reduced leptin levels substantially contribute to the suppression of pulmonary antibacterial host defense during starvation and that administration of this adipokine may be of therapeutic benefit clinically.

Topics: Acute Disease; Animals; Blood Glucose; Body Weight; Bronchoalveolar Lavage; Corticosterone; Disease Models, Animal; Fasting; Interleukin-6; Leptin; Leukocytes; Leukotriene B4; Lung; Mice; Mice, Inbred C57BL; Neutrophils; Phagocytosis; Pneumonia, Pneumococcal; Sodium Chloride; Starvation; Streptococcus pneumoniae

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

Leukotriene-generated effects on microvascular integrity and polymorphonuclear leukocytes (PMNL) play a key role in the inflammatory process of the alveolar-capillary unit in neonatal acute respiratory distress syndrome. We asked if intrapulmonary application of MK886, a 5-lipoxygenase inhibitor, and the use of a porcine surfactant preparation (Curosurftrade mark) as a carrier substance would improve lung function in a neonatal piglet model of airway lavage. Anesthetized, mechanically ventilated newborn piglets (n = 19) underwent repeated airway lavage to induce acute lung injury. Piglets then received either surfactant alone (S, n = 6), or MK886 admixed with surfactant (S + MK, n = 7), or an air-bolus injection as control (C, n = 6). Measurements of gas exchange, lung function, extravascular lung water (EVLW), cell counts, and leukotriene B(4) (LTB(4)) concentrations in bronchoalveolar lavage fluid (BAL) were performed during 6 hr of mechanical ventilation. Arterial oxygen partial pressure (PaO(2)) (S, 13.8 +/- 4.2 kPa, vs. S + MK, 20 +/- 6.6; P < 0.05), functional residual capacity (S, 15.1 +/- 6.8 ml/kg, vs. S + MK, 18.8 +/- 3.7 ml/kg; P < 0.05), and EVLW (S, 29 +/- 14 ml/kg, vs. S + MK 24 +/- 4 ml/kg; P < 0.05) were significantly improved in the MK886 group. This clinical effect was linked with a decrease in LTB(4) concentration in BAL (S, 3.5 (1.9-5.4) pg/ml, vs. S + MK, 1.6 (0.7-4.7) pg/ml; P < 0.05) and an increase in IL-8 (S, 2,103 (852-4,243) pg/ml, vs. S + MK, 3,815 (940-26,187) pg/ml; P < 0.05). PMNL counts in BAL were reduced (S, 570 +/- 42 cells/ml, vs. 275 +/- 35 cells/ml; P < 0.05). In conclusion, intrapulmonary application of the 5-lipoxygenase inhibitor MK886 with surfactant as a carrier improves lung function by decreasing EVLW as the main response to LTB(4) reduction.

Topics: Animals; Animals, Newborn; Biological Products; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Female; Hemodynamics; Humans; Indoles; Infant, Newborn; Interleukin-8; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Male; Phospholipids; Pulmonary Edema; Pulmonary Gas Exchange; Respiration, Artificial; Respiratory Distress Syndrome, Newborn; Swine

To investigate the role of leukotriene B4 (LTB4) and its receptor BLT1 in the pathogenesis of mouse uveitis.. Experimental autoimmune uveitis (EAU) was induced in B10RIII mice by immunization of interphotoreceptor retinoid binding protein (IRBP; peptide sequence 161-180) or in C57BL/6 (B6) mice by transfer of activated T cells specific for IRBP1-20. The animals were then treated with and without the BLT1 receptor antagonist, CP105696, at the disease onset after immunization or at day 0 or day 6 after T-cell transfer. EAU was also induced in wild-type B6 (WT) and BLT1-deficient (BLT1-/-) mice by reciprocal transfer of the T cells from B6 to BLT1-deficient mice and vise versa. Clinical signs of inflammation and ocular histology were compared. The chemotactic activity of LTB4 on naïve and IRBP-specific autoreactive T cells as well as effector leukocytes was examined.. The treatment of CP105696, greatly reduced the intensity of ongoing disease. IRBP1-20-specific T cells derived from wild-type B6 mice induced only mild uveitis in syngeneic BLT1-deficient mice and that IRBP1-20-specific T cells derived from BLT1-/- mice induced milder disease in wild-type B6 mice than those derived from wild-type B6 mice, suggesting that expression of the LTB4 receptor on both activated autoreactive T cells and effector leukocytes was necessary for ocular inflammation to occur. Consistent with these data, transfer of autoreactive T cells from B6 mice to 5-lipoxygenase-deficient (5-LO-/-) mice, which have a functional defect in LTB4 expression, also failed to induce uveitis in the recipient mice.. The results demonstrate a critical role for LTB4 in ocular inflammation and in the development and progression of EAU and suggest a new potential target for therapeutic intervention in this disease.

Topics: Adoptive Transfer; Animals; Arachidonate 5-Lipoxygenase; Autoimmune Diseases; Benzopyrans; Carboxylic Acids; Cells, Cultured; Chemotaxis, Leukocyte; Disease Models, Animal; Eye Proteins; Female; Immunization; Leukotriene B4; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Mice, Knockout; Peptide Fragments; Purinergic P2 Receptor Antagonists; Receptors, Leukotriene B4; Receptors, Purinergic P2; Retinol-Binding Proteins; T-Lymphocytes; Uveitis

An increasing prevalence of allergic diseases, such as atopic dermatitis, allergic rhinitis and bronchial asthma, has been noted worldwide. Allergic asthma strongly correlates with airway inflammation caused by the unregulated production of cytokines secreted by allergen-specific type-2 T helper (Th2) cells. This study aims to explore the therapeutic effect of the airway gene transfer of IL-12, IL-10 and TGF-beta on airway inflammation in a mouse model of allergic asthma.. BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injections with OVA and challenged by nebulized OVA. Different cytokine gene plasmids or non-coding vector plasmids were instilled daily into the trachea up to one day before the inhalatory OVA challenge phase.. Intratracheal administration of IL-10, IL-12 or TGF-beta can efficiently inhibit antigen-induced airway hyper-responsiveness and is able to largely significantly lower the number of eosinophils and neutrophils in bronchoalveolar lavage fluid of ovalbumin (OVA) sensitized and challenged mice during the effector phase. Furthermore, the effect of IL-10 plasmids is more remarkable than any other cytokine gene plasmid. On the other hand, local administration of IL-4 gene plasmids before antigen challenge can induce severe airway hyper-responsiveness (AHR) and airway eosinophilia.. Our data demonstrated that anti-inflammatory cytokines, particularly IL-10, have the therapeutic potential for the alleviation of airway inflammation in murine model of asthma.

Topics: Animals; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Chemokine CCL11; Chemokines, CC; Disease Models, Animal; Female; Gene Transfer Techniques; Interleukin-10; Interleukin-12; Interleukin-4; Leukotriene B4; Mice; Mice, Inbred BALB C; Ovalbumin; Pulmonary Eosinophilia; Transforming Growth Factor beta

1. The antinociceptive effect of risedronate in experimental pain models in rats and mice was investigated in the present study. 2. Rats received zymosan intra-articularly (i.art.) into the right knee joint and the nociceptive response was assessed using the articular incapacitation test. Joint washouts were used for determining cell influx, tumour necrosis factor (TNF)-alpha and leukotriene (LT) B4 levels. 3. Mice received either zymosan (1 mg) or acetic acid (0.6%) i.p. and the nociceptive response was measured as the number of writhings between 0 and 30 min after the stimuli. Control animals received i.p. injections of saline. 4. Groups were pretreated with risedronate (5-500 microg/kg, s.c.) and compared with vehicle (saline)-treated (NT) animals. One group of rats was cotreated with the micro-opioid receptor antagonist naloxone (2 mg/kg, s.c.) prior to risedronate, followed by 1 mg zymosan i.art. 5. Risedronate, at 100 and 500 microg/kg, significantly and dose-dependently inhibited the nociceptive response in the writhings test (P < 0.05), inhibiting responses to acetic acid by 65.4 and 49.2%, respectively, and to zymosan by 72.9 and 71.9%, respectively. 6. Pretreatment with risedronate also significantly (P < 0.05) and dose-dependently inhibited the articular incapacitation in zymosan-arthritis. 7. Risedronate, at 50 microg/kg, significantly inhibited TNF-alpha release as compared with the NT group (39.4 +/- 9.8 vs 145.6 +/- 43.3 pg/mL TNF-alpha, respectively). 8. Risedronate, at 50 and 100 microg/kg, significantly inhibited LTB4 release into the joints compared with the NT group (2883.1 +/- 73.2, 1911.5 +/- 205.3 and 4709.9 +/- 237.2 pg/mL, respectively). These effects of risedronate were associated with a significant reduction in the inflammatory cell infiltration. 9. Cotreatment with risedronate and naloxone did not reverse the antinociceptive effects of risedronate in zymosan-arthritis. 10. This is the first demonstration that risedronate displays intrinsic antihypernociceptive activity. This effect is associated with reduced cell infiltration and inhibition of TNF-alpha and LTB4 release and is not linked to an endogenous opioid-release mechanism.

Topics: Acetic Acid; Analgesics; Animals; Anti-Inflammatory Agents; Arthritis, Experimental; Diphosphonates; Disease Models, Animal; Dose-Response Relationship, Drug; Etidronic Acid; Inflammation; Leukotriene B4; Male; Mice; Pain; Pain Measurement; Rats; Rats, Wistar; Risedronic Acid; Tumor Necrosis Factor-alpha; Zymosan

Licofelone is an analogue of arachidonic acid that inhibits 5-lipoxygenase (LOX), cyclooxygenase (COX)-1 and COX-2. We investigated the effects of licofelone on cardiovascular derangements and production of thromboxane (Tx)A(2) induced by the inflammatory agonist n-formyl-methionyl-leucyl-phenylalanine (fMLP) in the rabbit, in comparison with those of aspirin or rofecoxib, inhibitors of COX-1 and COX-2, respectively. In control rabbits, injection of fMLP (30 nmol/kg) in the jugular vein evokes ischemic electrocardiographic (ECG) changes in the first 1-5 min, i.e. a profound depression of the ST segment and inversion of the T wave. Simultaneously, fMLP induces bradycardia and hypotension and increases TxB(2) blood levels. All changes are transient. Licofelone (60 mg/kg/5 days, p.os) prevented fMLP-induced ECG ischemic changes in all treated animals, reverted bradycardia and hypotension, and significantly reduced TxB(2). Aspirin (10 mg/kg/5 days, p.os) prevented ischemic ECG alterations in 2 out of 5 treated animals and did not modify either bradycardia or hypotension. One rabbit died two min after fMLP. In 2 rabbits, aspirin reduced TxB(2) levels by more than 80% respect to mean control values; the remaining two rabbits produced an amount of TxB(2) similar to controls. These two rabbits also showed ischemic ECG changes. Rofecoxib (10 mg/kg/5 days, p.os) did not prevent fMLP-induced ischemic ECG alteration, bradycardia and hypotension, and did not significantly modify the increase of TxB(2). These results indicate that the capacity of licofelone to efficiently suppress TxA(2) production, is responsible for the protection from the cardiovascular derangement triggered by an inflammatory stimulus.

Topics: Acetates; Animals; Aspirin; Blood Pressure; Cyclooxygenase Inhibitors; Disease Models, Animal; Electrocardiography; Heart Rate; Inflammation; Lactones; Leukotriene B4; Lipoxygenase Inhibitors; Male; Myocardial Ischemia; N-Formylmethionine Leucyl-Phenylalanine; Pyrroles; Rabbits; Sulfones; Thromboxane A2; Time Factors

Lactulose is a drug used as a laxative that has been shown to promote the growth of lactobacilli and bifidobacteria, acting as a prebiotic and with a potential beneficial effect in inflammatory bowel disease. The present study describes the preventive antiinflammatory activity of lactulose in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis.. Rats were rendered colitic by a colonic instillation of 10 mg of TNBS dissolved in 0.25 mL of 50% ethanol. One group of colitic rats received lactulose, which was incorporated in the drinking water (2.5% wt/vol) for 2 weeks before TNBS instillation, and colonic damage was evaluated 1 week after colitis induction. Different biochemical markers of colonic inflammation were assayed: myeloperoxidase activity, glutathione content, tumor necrosis factor alpha, leukotriene B4 levels, and colonic inducible nitric oxide synthase expression. In addition, bacterial counts (for lactobacilli and bifidobacteria) were performed in colonic contents from colitic rats.. The results show that lactulose exerted a preventive antiinflammatory effect in this model of rat colitis, as evidenced by a significant reduction of myeloperoxidase activity and by a decrease of both colonic tumor necrosis factor alpha and leukotriene B4 production. This effect was also characterized by an inhibition of colonic inducible nitric oxide synthase expression, which is unregulated as a consequence of the inflammatory status. This beneficial effect was associated with increased levels of lactobacilli and bifidobacteria species in colonic contents in comparison with untreated colitic rats.. In conclusion, the intestinal antiinflammatory effect of lactulose could be related to its prebiotic properties, supporting its potential use in human inflammatory bowel disease.

Topics: Animals; Colitis; Disease Models, Animal; Female; Gastrointestinal Agents; Lactobacillaceae; Lactulose; Leukotriene B4; Peroxidase; Rats; Rats, Wistar; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha

The present study was planned to evaluate the individual and combined effects of selective cyclooxygenase-2 (COX-2) inhibitor, celecoxib, and omega-3 fatty acid on the gingival tissue levels of prostaglandin E2 (PGE2), prostaglandin F2alpha (PGF2alpha), leukotriene B4 (LTB4), and platelet activating factor (PAF) in endotoxin-induced periodontitis in rats.. Experimental periodontitis was induced by repeated injection of Escherichia coli endotoxin (LPS). Forty-four adult male Sprague-Dawley rats were divided into five study groups: saline control, LPS, celecoxib, omega-3 fatty acid, and combination celecoxib and omega-3 fatty acid. Celecoxib and omega-3 fatty acid were given either as a single agent or as a combination therapy during 14 days of the study period. At the end of the 2-week protocol, the rats were sacrificed, the gingival tissues were dissected and extracted, and the extracts were analyzed for PGE2, PGF2alpha, and LTB4 levels by enzyme immunoassay and for PAF levels by radioimmunoassay. The defleshed jaws were analyzed morphometrically for alveolar bone loss. Data were evaluated statistically by using parametric tests.. LPS injection resulted in significantly more bone loss than the saline controls (P<0.05) and significant elevations in the gingival tissue levels of all the analyzed mediators except PGF2alpha. Individual administration of celecoxib revealed significant reductions in PGE2 and PAF levels (P <0.05), while omega-3 fatty acid provided significant reduction in PGE2, PGF2alpha, and LTB4 levels compared to the LPS group (P <0.05). Combined administration of celecoxib and omega-3 fatty acid exhibited significantly lower values than those of the LPS group in all the analyzed membrane phospholipid mediators (P <0.05), which approximated the levels in the saline control group (P>0.05).. The results of the present study indicate that celecoxib and omega-3 fatty acid, when used individually, show a rather partial effect on the control of the analyzed mediators, but when combined they show a synergic effect and provide significant reductions in the gingival tissue levels of PGE2, PGF2alpha, LTB4, and PAF in LPS-induced experimental periodontitis. These findings may pioneer further clinical human studies investigating the possible place of celecoxib and omega-3 fatty acid in periodontal treatment.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Celecoxib; Cyclooxygenase Inhibitors; Dinoprost; Dinoprostone; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Endotoxins; Fatty Acids, Omega-3; Leukotriene B4; Male; Periodontitis; Platelet Activating Factor; Pyrazoles; Rats; Rats, Sprague-Dawley; Sulfonamides

In the present study, we investigated the involvement of macrophage-inflammatory protein-1alpha (MIP-1alpha)[CC chemokine ligand 3 (CCL3)], MIP-1beta[CCL4], regulated on activation, normal T expressed and secreted (RANTES)[CCL5], and CC chemokine receptors (CCRs) on neutrophil migration in murine immune inflammation. Previously, we showed that ovalbumin (OVA)-triggered neutrophil migration in immunized mice depends on the sequential release of tumor necrosis factor alpha (TNF-alpha) and leukotriene B(4)(LTB(4)). Herein, we show increased mRNA expression for MIP-1alpha[CCL3], MIP-1beta[CCL4], RANTES[CCL5], and CCR1 in peritoneal cells harvested from OVA-challenged, immunized mice, as well as MIP-1alpha[CCL3] and RANTES[CCL5] but not MIP-1beta[CCL4] proteins in the peritoneal exudates. OVA-induced neutrophil migration response was muted in immunized MIP-1alpha[CCL3](-/-) mice, but it was not inhibited by treatment with antibodies against RANTES[CCL5] or MIP-1beta[CCL4]. MIP-1alpha[CCL3] mediated neutrophil migration in immunized mice through induction of TNF-alpha and LTB(4) synthesis, as these mediators were detected in the exudates harvested from OVA-challenged immunized wild-type but not MIP-1alpha[CCL3](-/-) mice; administration of MIP-1alpha[CCL3] induced a dose-dependent neutrophil migration, which was inhibited by treatment with an anti-TNF-alpha antibody in TNF receptor 1 (p55(-/-))-deficient mice or by MK 886 (a 5-lipoxygenase inhibitor); and MIP-1alpha[CCL3] failed to induce LTB(4) production in p55(-/-) mice. MIP-1alpha[CCL3] used CCR1 to promote neutrophil recruitment, as OVA or MIP-1alpha[CCL3] failed to induce neutrophil migration in CCR1(-/-) mice, in contrast to CCR5(-/-) mice. In summary, we have demonstrated that neutrophil migration observed in this model of immune inflammation is mediated by MIP-1alpha[CCL3], which via CCR1, induces the sequential release of TNF-alpha and LTB(4). Therefore, whether a similar pathway mediates neutrophil migration in human immune-inflammatory diseases, the development of specific CCR1 antagonists might have a therapeutic potential.

Topics: Animals; Antibodies; Autoimmune Diseases; Chemokine CCL3; Chemokine CCL4; Chemokine CCL5; Chemokines, CC; Chemotaxis, Leukocyte; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Inflammation; Leukotriene B4; Macrophage Inflammatory Proteins; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Ovalbumin; Receptors, CCR1; Receptors, Chemokine; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; RNA, Messenger; Signal Transduction; Tumor Necrosis Factor Decoy Receptors; Tumor Necrosis Factor-alpha; Up-Regulation

The potential therapeutic effect of low-viscosity sodium alginate (LVA) was studied in a rat model of acute colitis induced by intracolonic administration of acetic acid. This experimental model produced a significant ulcerative colitis. Induction of colitis also significantly enhanced the serum and colonic mucosal cytokine (IL-6 and TNF-alpha) and eicosanoid (LTB4 and PGE2) levels, which paralleled with the severity of colitis. LVA solution was administered orally as drinking water at concentration of 0.5% (W/V) for 1 week. The tolerability and inhibitory effect of LVA on matrix metalloproteinase-2 (MMP-2) were tested using WEHI-164 cell line and zymography method. The results showed that LVA therapy is able to significantly reduce colonic damage score, histological lesion, serum and colonic mucosal IL-6, TNF-alpha, LTB4 and PGE2 levels in treated group compared with nontreated controls. Moreover, in vitro examinations revealed that treatment with LVA could diminish MMP-2 activity. It is concluded that LVA is able to suppress acetic acid-induced colitis in rats. Some of the action of LVA may be associated with its inhibitory effects on cytokine and eicosanoid production and MMP-2 activity. Our data suggest that LVA could potentially be a novel therapeutic option for inflammatory bowel disease.

Topics: Alginates; Animals; Cell Line, Tumor; Colitis, Ulcerative; Dinoprostone; Disease Models, Animal; Electrophoresis, Polyacrylamide Gel; Female; Glucuronic Acid; Hexuronic Acids; Histocytochemistry; Humans; Interleukin-6; Intestinal Mucosa; Leukotriene B4; Matrix Metalloproteinase 2; Matrix Metalloproteinase Inhibitors; Random Allocation; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha

Neutrophil elastase (NE) is a factor that aggravates colitis. We investigated the influence of thromboxane A2 (TXA2) and leukotriene B4 (LTB4) on NE release in Syrian hamsters with trinitrobenzene sulfonic acid-induced colitis. Colonic specimens with colitis were incubated with U-46619 (a TXA2 analogue) or LTB4 in vitro and NE release was examined. As a result, U-46619 increased NE release, while LTB4 had no effect. The NE release induced by U-46619 was inhibited by a TP-receptor antagonist. To demonstrate that TXA2 caused NE release in vivo as well, while LTB4 did not, colitis animals were treated with nordihydroguaiaretic acid (NDGA), a dual inhibitor of cyclooxygenase/lipoxygenase; and colonic luminal TXB(A)2 and LTB4 levels and NE activity were determined. The TXB(A)2 level was significantly correlated with NE activity, while no correlation was found between LTB4 and NE activity. An inhibitory effect of NDGA on the ulcer area was also observed, and NE activity was significantly correlated with the ulcer area. The suppression of TXA2 production by NDGA may result in the inhibition of NE release so that colonic tissue damage becomes less severe. Regulation of NE release is a new biological action of TXA2 that has not been reported before.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Colitis; Cricetinae; Disease Models, Animal; Leukocyte Elastase; Leukotriene B4; Male; Mesocricetus; Specific Pathogen-Free Organisms; Thromboxane A2; Trinitrobenzenesulfonic Acid; Up-Regulation

Late-phase airway hyperresponsiveness (AHR) in asthma is considered the event leading to persistent inflammation in the lungs, but the molecular mechanisms involved in this process are poorly understood.. To examine the role of TNF-alpha in the development of a late AHR and airway inflammation in asthma.. We established a murine model of asthma with not only biphasic AHR to methacholine but also airway eosinophilia. The effect of TNF-alpha blockade was determined by using anti-TNF-alpha antibody and TNF-alpha knockout mice. Cytosolic phospholipase A(2) (cPLA(2)) mRNA expression and activity were assessed by using RT-PCR and 1-stearoyl-2-[1-(14)C] arachidonyl-sn-glycero-3-phosphocholine as the substrate, respectively.. TNF-alpha blockade resulted in significant inhibition of the late AHR without affecting the early AHR, and reduction in airway eosinophilia and inflammation. cPLA(2) activity was increased in asthmatic lungs in a TNF-alpha-dependent way, and cPLA(2) inhibitor blocked late AHR and airway eosinophilia. TNF-alpha also stimulated the synthesis of cPLA(2) metabolites such as leukotriene B(4) and platelet-activating factor in the airway. Specific inhibitors of cPLA(2) metabolites inhibited the late AHR and airway eosinophilia.. TNF-alpha is the proximal key cytokine capable of developing late-phase AHR and subsequent airway inflammation through expression/activation of cPLA(2).

Topics: Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchoconstrictor Agents; Cytosol; Disease Models, Animal; Enzyme Activation; Histamine; Inflammation; Leukotriene B4; Male; Methacholine Chloride; Mice; Mice, Inbred BALB C; Mice, Knockout; Phospholipases A; Platelet Activating Factor; Pulmonary Eosinophilia; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Necrosis Factor-alpha

Bronchial asthma is an increasingly common disorder that remains poorly understood and difficult to manage. The disease is characterized by airway hyperresponsiveness, chronic inflammation, and mucus overproduction. Based on the finding that leukotriene B4 receptor 1 (BLT1) is expressed highly in Th2 lymphocytes, we analyzed the roles of BLT1 using an OVA-induced bronchial asthma model. BLT1-null mice did not develop airway hyperresponsiveness, eosinophilic inflammation, and hyperplasia of goblet cells. Attenuated symptoms were accompanied by reduced IgE production, and accumulation of IL-5 and IL-13 in bronchoalveolar lavage fluid, suggesting attenuated Th2-type immune response in BLT1-null mice. Peribronchial lymph node cells of sensitized BLT1-null mice showed much attenuated proliferation and production of Th2 cytokines upon re-stimulation with Ag in vitro. Thus, LTB4-BLT1 axis is required for the development of Th2-type immune response, and blockade of LTB4 functions through BLT1 would be novel and useful in the effort to ameliorate bronchial asthma and related Th2-biased immune disorders.

Topics: Animals; Asthma; Bronchial Hyperreactivity; Calcium; Disease Models, Animal; Immunity, Innate; Immunoglobulin E; Leukotriene B4; Lung; Mice; Mice, Knockout; Peroxidase; Receptors, Leukotriene B4; Respiratory System; Th2 Cells

The peroxisome proliferator-activated receptor system is exciting much interest as a novel point of therapeutic intervention in inflammation. Here, the effect of a peroxisome proliferator-activated receptor alpha agonist, [4-chloro-6-(2,3-xylidine)-pyrimidinylthio]acetic acid (Wy14,643), was examined in arachidonic acid-induced murine ear inflammation. 3-[1-(4-Chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]-2,2-dimethylpropanoic acid (MK886, a 5-lipoxygenase inhibitor) and indomethacin (a cyclo-oxygenase inhibitor) were used as reference compounds. Wy14,643 dose dependently inhibited ear swelling and polymorphonuclear leukocyte influx, as did MK886, associated with reduced tissue leukotriene B4 but not prostaglandin E2 levels. Unlike MK886, Wy14,643 did not inhibit ex vivo leukotriene B4 production. However, Wy14,643, but not MK886, induced peroxisomal enzyme activity. Indomethacin was less effective, though tissue prostaglandin E2 but not leukotriene B4 levels were reduced. Again, unlike indomethacin, Wy14,643 did not reduce ex vivo prostaglandin E2 production. However, indomethacin did increase peroxisomal enzyme activity but to a lesser extent than Wy14,643. This study demonstrates that peroxisome proliferator-activated receptor alpha activation can inhibit arachidonic acid-induced inflammation in part by enhancing degradation of leukotriene B4.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents; Arachidonate 5-Lipoxygenase; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Ear, External; Edema; Female; Indoles; Indomethacin; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Mice; Neutrophils; Palmitoyl Coenzyme A; Peroxisomes; PPAR alpha; Prostaglandin-Endoperoxide Synthases; Pyrimidines

This study investigated the effects of roflumilast, a PDE4 inhibitor, on slow-reacting substance of anaphylaxis (SRS-A)-mediated bronchoconstriction and pulmonary leukotriene (LT) release in ovalbumin (OVA)-sensitized and -challenged guinea pigs. Animals were treated with roflumilast orally (0.04, 0.12, 0.4, or 4 mg/kg) or placebo 1 hour before OVA challenge. Bronchoconstriction was quantified by measuring airway conductance (Gaw) and dynamic lung compliance (Cdyn). Roflumilast significantly attenuated the decrease in Gaw (50% inhibitory dose [ID50] = 0.33 mg/kg) and Cdyn (ID50 = 0.25 mg/kg) in a dose-dependent manner and significantly inhibited Cys-LT (ID50 = 0.06 mg/kg) and LTB4 (ID50 = 0.05 mg/kg) release versus placebo-treated animals. Roflumilast did not affect LTD4-induced bronchoconstriction. These findings support the role of roflumilast as an anti-inflammatory treatment for asthma.

Topics: Allergens; Aminopyridines; Animals; Benzamides; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Cyclopropanes; Cysteine; Disease Models, Animal; Guinea Pigs; Leukotriene B4; Leukotrienes; Male; Ovalbumin; Phosphodiesterase Inhibitors; SRS-A

1. Diosmectite is a natural silicate effectively used in the treatment of infectious diarrhoea. Its antidiarrhoeal properties involve adsorption of toxins and bacteria and modifications of the rheological characteristics of gastrointestinal mucus. Hence, the aim of this study was to test the intestinal anti-inflammatory activity of diosmectite. 2. Diosmectite (500 mg x kg(-1) day(-1), p.o.) was administered as a post-treatment to rats with chronic trinitrobenzene sulphonic acid colitis. Colonic status was checked 1 and 2 weeks after colitis induction by macroscopic, histological and biochemical examination. 3. Diosmectite post-treatment resulted in amelioration of the morphological signs (intestinal weight, macroscopic damage, necrosed area, histology) and biochemical markers (myeloperoxidase activity, glutathione levels, MUC2 expression, inducible nitric oxide synthase and interleukin-1beta (IL-1beta) and leukotriene B(4) synthesis), as well as in the reduction of the severity of diarrhoea. The effect of the clay was comparable to that of sulphasalazine (50 mg x kg(-1) day(-1)). 4. 5. Diosmectite exhibited a dose-dependent capacity to adsorb proteins in vitro as well as a dose-dependent inhibitory effect on the basolateral secretion of IL-8 by lipopolysaccharide (LPS)-stimulated HT29 cells. Diosmectite had a dose-dependent inhibitory effect on IL-1beta production by LPS-stimulated THP-1 cells. 6. The effect of diosmectite on MUC2 was post-transcriptional, since mRNA levels were unaffected. However, diosmectite is able to upregulate MUC2 mRNA levels in HT29-MTX cells. 7. Diosmectite has anti-inflammatory activity administered as a post-treatment. Possible mechanisms include adsorption of luminal antigens, increase of colonic mucin levels and possibly a direct modulatory action of cytokine production by mucosal cells.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Line; Colitis; Cytokines; Disease Models, Animal; Female; Glutathione; Glycoproteins; Haptens; Humans; Interleukin-1; Interleukin-1beta; Intestinal Mucosa; Leukotriene B4; Mucins; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Peptide Fragments; Rats; Rats, Wistar; Silicates; Trinitrobenzenesulfonic Acid

A standard aqueous extract of Mangifera indica L., used in Cuba as an antioxidant under the brand name of VIMANG, was tested in vivo for its anti-inflammatory activity using commonly accepted assays. M. indica extract, administered topically (0.5-2 mg per ear), reduced ear edema induced by arachidonic acid (AA) and phorbol myristate acetate (PMA, ED50 = 1.1 mg per ear) in mice. In the PMA model, M. indica extract also reduced myeloperoxidase (MPO) activity. This extract p.o. administered also inhibited tumor necrosis factor alpha (TNFalpha) serum levels in both models of inflammation (AA, ED50 = 106.1 mg kg(-1) and PMA, ED50 = 58.2 mg kg(-1)). In vitro studies were performed using the macrophage cell line RAW264.7 stimulated with pro-inflammatory stimuli (LPS-IFNgamma or the calcium ionophore A23187) to determine PGE2 or LTB4 release, respectively. The extract inhibited the induction of PGE2 with IC50 = 64.1 microg ml(-1) and LTB4 IC50 = 22.9 microg ml(-1). M. indica extract also inhibited human synovial secretory phospholipase (PL)A2 with IC 50 = 0.7 microg ml(-1). These results represent an important contribution to the elucidation of the mechanism involved in the anti-inflammatory and anti-nociceptive effects reported by the standard M. indica extract VIMANG.

Topics: Administration, Topical; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Calcimycin; Cuba; Dexamethasone; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Drug Therapy, Combination; Ear, External; Edema; Eicosanoids; Indomethacin; Interferon-gamma; Leukotriene B4; Lipopolysaccharides; Macrophages; Male; Mangifera; Mice; Oleanolic Acid; Peroxidase; Phospholipases A; Phytotherapy; Plant Bark; Plant Extracts; Plant Stems; Plants, Medicinal; Tetradecanoylphorbol Acetate; Tumor Necrosis Factor-alpha; Water; Xanthones

The role of 5-lipoxygenase (5-LOX) in the pathophysiology of renal ischemia/reperfusion (I/R) injury is not known. Here we investigate the effects of 1) the 5-LOX inhibitor zileuton and 2) 5-LOX gene knockout (5-LOX(-/-)) mice on renal dysfunction and injury caused by I/R of the kidney in mice. Wild-type mice treated with zileuton (3 mg/kg i.v.) or 5-LOX(-/-) mice were subjected to bilateral renal artery occlusion (30 min) followed by reperfusion (24 h). Plasma urea, creatinine, and aspartate aminotransferase (AST) were measured as markers of renal dysfunction and reperfusion injury. Kidneys were used for histological evaluation of renal injury. Renal myeloperoxidase activity was measured and used as an indicator of polymorphonuclear leukocyte (PMN) infiltration and renal expression of intercellular adhesion molecule-1 (ICAM-1) was determined using immunohistochemistry. Administration of zileuton before I/R significantly reduced the degree of renal dysfunction (urea, creatinine) and injury (AST, histology). In addition, zileuton reduced the expression of ICAM-1 and the associated PMN infiltration caused by I/R of the mouse kidney. Compared with wild-type mice, the degree of renal dysfunction, injury, and inflammation caused by I/R in 5-LOX(-/-) mice was also significantly reduced, confirming the pathophysiological role of 5-LOX in the development of renal I/R injury. We propose that 1) endogenous 5-LOX metabolites enhance the degree of renal injury, dysfunction, and inflammation caused by I/R of the kidney by promoting the expression of adhesion molecules, and 2) inhibitors of 5-LOX may be useful in the treatment of conditions associated with I/R of the kidney.

Topics: Animals; Arachidonate 5-Lipoxygenase; Disease Models, Animal; Hydroxyurea; Inflammation; Intercellular Adhesion Molecule-1; Ischemia; Kidney Diseases; Leukotriene B4; Lipoxygenase Inhibitors; Mice; Mice, Knockout; Neutrophils; Peroxidase; Reperfusion Injury

Aberrant arachidonic acid (AA) metabolism, especially through the cyclooxygenase (Cox) and 5-lipoxygenase (5-Lox) pathways, has been suggested to play an important role in the development of esophageal adenocarcinoma (EAC). The purpose of this study was to investigate the expression of 5-Lox in EAC of a rat model and in human samples as well as the chemopreventive effects of zileuton (a specific 5-Lox inhibitor) and celecoxib (a specific Cox2 inhibitor) in the rat EAC model.. 5-Lox expression in EAC of a rat esophagogastroduodenal anastomosis model and of humans was examined with immunohistochemistry. A chemoprevention study was designed to test whether zileuton and celecoxib could suppress aberrant AA metabolism and esophageal adenocarcinogenesis.. With immunohistochemistry, we found that 5-Lox was overexpressed during esophageal adenocarcinogenesis in our rat model and in humans. In the chemoprevention study, EAC incidence was reduced in a dose-dependent manner from 68.8% (11 of 16) to 44.4% (8 of 18; P > 0.05) and 31.3% (5 of 16; P < 0.05) by 500 and 1,000 ppm zileuton, respectively, and to 33.3% (7 of 21; P < 0.05) and 20% (3 of 15; P < 0.05) by 500 and 1,000 ppm celecoxib, respectively. With isobolographic analysis, zileuton and celecoxib, both at a dose of 500 ppm, had an additive effect by reducing the tumor incidence to 16.7% (3 of 18, P < 0.01). Leukotriene B4 and prostaglandin E2 levels in the esophageal tissues were also significantly reduced by zileuton and celecoxib.. This study clearly demonstrated that 5-Lox and Cox2 play important roles in the development of EAC. Both zileuton and celecoxib had inhibitory effects on esophageal adenocarcinogenesis through inhibition on their respective enzymes of AA metabolism.

Topics: Adenocarcinoma; Anastomosis, Surgical; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Body Weight; Celecoxib; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Therapy, Combination; Esophageal Neoplasms; Humans; Hydroxyurea; Immunohistochemistry; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pyrazoles; Rats; Rats, Sprague-Dawley; Sulfonamides; Time Factors

Silsosangami is a dried decoctum of a mixture of seven Korean herbal medicine, which is consisted of seven herbs (indicated as concentrations) of Typhae Pollen, Pteropi Faeces, Paeoniae Radicis rubra, Cnidii Rhizoma, Persicae Semen, Carthami Flos and Curcumae Tuber. In the present study, the effects of Silsosangami water extract (SSG) on hemolysis in human blood were studied. Using an in vitro system, only Curcumae Tuber, Persicae Semen and Paeoniae Radicis rubra had the strongest effects on hemolysis; Typhae Pollen and Pteropi Faeces had the slight effects; and Cnidii Rhizoma and Carthami Flos had no effect. On the other hand, the SSG inhibited neutrophil functions, including degranulation, superoxide generation, and leukotriene B4 production, without any effect on 5-lipoxygenase activity. This SSG reduced nitric oxide (NO) and prostaglanin E2 (PGE2) production in mouse peritoneal macrophages stimulated with lipopolysaccharide, without the influence on the activity of inducible NO synthase (iNOS), cyclooxygenase COX-2 and COX-1 being observed. SSG significantly reduced mouse paw oedema induced by carrageenan. Western blot analysis showed that SSG reduced the expression of iNOS and COX-2. These results suggested that SSG might be used as a novel antithrombotic therapeutic agents in post-myocardial infarction and also, indicated that SSG exerts anti-inflammatory effects related to the inhibition of neutrophil functions and of NO and PGE2 production, which could be due to a decreased expression of iNOS and COX-2.

Topics: Animals; Anti-Inflammatory Agents; Carrageenan; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Edema; Erythrocytes; Gene Expression; Hemolysis; Herbal Medicine; Humans; Korea; Leukotriene B4; Macrophages, Peritoneal; Medicine, East Asian Traditional; Membrane Proteins; Mice; Neutrophils; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Pancreatic Elastase; Phytotherapy; Plant Extracts; Prostaglandin-Endoperoxide Synthases; Thromboxane B2

A new lipidic acid-amido ether derivative (LAAE-14) able to reduce dose-dependently the calcium increases mediated either by calcium ionophore ionomycin, by the endoplasmic reticular Ca(2+)-ATPase inhibitor thapsigargin, or by the chemotactic tripeptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), in human neutrophils as well as in murine peritoneal macrophages, but not ATP, has been evaluated as a potential anti-inflammatory drug. This compound attenuated leukocyte activation by means of its inhibitory effect on the respiratory burst elicited in both types of cells by 12-O-tetradecanoyl phorbol 13-acetate, by inhibition of the degranulation process induced by cytochalasin B+fMLP or cytochalasin B+platelet activating factor, as well as by reduction of leukotriene B(4) synthesis induced by the calcium ionophore A23187. In addition, in zymosan-stimulated mouse peritoneal macrophages LAAE-14 caused a potent inhibition of nitrite and prostaglandin E(2) production. This compound exerted acute and chronic anti-inflammatory effects by oral route, that may be related with several mechanisms such as attenuation of leukocyte activation, inhibition of inducible nitric oxide synthase, cyclo-oxygenase-2 and cytosolic phospholipase A(2) expression as well as reduction in tumour necrosis factor-alpha production. Its anti-inflammatory profile is clearly correlated with its behavior as inhibitor of intracellular calcium mobilization. The profile and potency of this compound may have relevance for the inhibition of the inflammatory response at different levels and may represent a new approach to the development of new anti-inflammatory drugs.

Topics: Acute Disease; Animals; Arthritis, Experimental; Calcium; Carrageenan; Cell Movement; Chronic Disease; Dinoprostone; Disease Models, Animal; Edema; Humans; Inflammation; Leukotriene B4; Luminescent Measurements; Macrophages, Peritoneal; Mice; Neutrophils; Nitrites; Pancreatic Elastase; Rats; Tumor Necrosis Factor-alpha; Zymosan

Leukotriene B4 (LTB4) was originally described as a potent lipid myeloid cell chemoattractant, rapidly generated from innate immune cells, that activates leukocytes through the G protein-coupled receptor BLT1. We report here that BLT1 is expressed on effector CD4+ T cells generated in vitro as well as in vivo when effector T cells migrate out of the lymphoid compartment and are recruited into peripheral tissues. BLT1 mediated LTB4-induced T helper type 1 (T(H)1) and T(H)2 cell chemotaxis and firm adhesion to endothelial cells under flow, as well as early CD4+ and CD8+ T cell recruitment into the airway in an asthma model. Our findings show that the LTB4-BLT1 pathway is involved in linking early immune system activation and early effector T cell recruitment.

Topics: Animals; Asthma; Bronchoalveolar Lavage Fluid; CD4-Positive T-Lymphocytes; Chemotaxis, Leukocyte; Disease Models, Animal; Female; Flow Cytometry; Immunoglobulin E; Immunoglobulin G; Leukotriene B4; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Receptors, Leukotriene B4; T-Lymphocyte Subsets

Although a dextran sodium sulfate (DSS)-induced colitis is commonly used as an ulcerative colitis (UC) model in adult rodents, there are no studies using this model in young animals. We examined differences in the severity of DSS-induced colitis as a function of the concentration of DSS administered and sought to establish a DSS-induced colitis model in young rats.. We administrated different concentrations of DSS solution (2%, 3%, and 4%) to 4-week-old weanling rats and compared their clinical findings, colonic histologic findings, mucosal leukotriene B4 (LTB4) production, and mucosal blood flow with control weanling rats and 8-week-old adult rats given 4% DSS for induced colitis.. Clinical symptoms, such as diarrhea and rectal bleeding, histologic findings, and disturbance of mucosal microcirculation in weanling rats given 4% DSS were significantly more severe than those in adult rats given the same treatment. Three of 10 rats given 2% DSS had no bloody stool and 2 of 10 rats given 4% DSS died during the experimental periods. Clinical symptoms, hemoglobin levels, histologic damage scores, mucosal LTB4 production, and mucosal blood flow became more severely deranged as the concentration of DSS increased from 2% to 4%.. These findings suggest that we can adjust disease severity in UC model for young children by giving different concentrations of DSS to weanling rats.

Topics: Aging; Animals; Colitis; Colon; Dextran Sulfate; Diarrhea; Disease Models, Animal; Dose-Response Relationship, Drug; Gastrointestinal Hemorrhage; Intestinal Mucosa; Leukotriene B4; Male; Rats; Rats, Wistar; Weaning

Nonsteroidal anti-inflammatory drugs (e.g., indomethacin) inhibit and reduce the fluid secretion responses elicited by cholera toxin (CT), but it has not been conclusively determined which cyclooxygenase (COX) isoform is involved in CT's action. This study evaluated the role of the COX enzymes and their arachidonic acid metabolites in experimental cholera. Swiss-Webster mice were dosed with celecoxib and rofecoxib and challenged with CT in ligated small intestinal loops, and intestinal segments from mice deficient in COX-1 and COX-2 were challenged with CT. The effects of CT on fluid accumulation, prostaglandin E(2) production, mucosal tissue injury, and markers of oxidative stress were measured. Celecoxib and rofecoxib given at 160 micro g per mouse inhibited CT-induced fluid accumulation by 48% and 31%, respectively, but there was no significant difference among cox-1(-/-) and cox-2(-/-) mice in response to CT compared to wild-type controls. CT elevated tissue levels of oxidized glutathione and lipid peroxides and elicited small intestinal tissue injury in two of five cox-1(-/-) and four of five cox-2(-/-) mice. A role for COX-2 in CT's mechanism of action has previously been suggested by the effectiveness of COX-2 inhibitors in reducing CT-induced fluid secretion, but CT challenge of COX-1 and COX-2 knockout mice did not corroborate the pharmacological data. The results of this study show that CT induced oxidative stress in COX-deficient mice and suggest a tissue-protective role for arachidonic acid metabolites in the small intestine against oxidative stress.

Topics: Aldehydes; Animals; Celecoxib; Cholera; Cholera Toxin; Cyclooxygenase 1; Cyclooxygenase 2; Disease Models, Animal; Female; Glutathione; Isoenzymes; Lactones; Leukotriene B4; Malondialdehyde; Membrane Proteins; Mice; Mice, Inbred C57BL; Oxidative Stress; Prostaglandin-Endoperoxide Synthases; Pyrazoles; Sulfonamides; Sulfones; Tumor Necrosis Factor-alpha

The production of nitric oxide (NO) by gamma interferon (IFN-gamma)-activated macrophages is a major effector mechanism during experimental Trypanosoma cruzi infection. In addition to IFN-gamma, chemoattractant molecules, such as platelet-activating factor (PAF) and CC chemokines, may also activate macrophages to induce NO and mediate the killing of T. cruzi in an NO-dependent manner. Here we investigated the ability of leukotriene B(4) (LTB(4)) to induce the production of NO by macrophages infected with T. cruzi in vitro and whether NO mediated LTB(4)-induced parasite killing. The activation of T. cruzi-infected but not naive murine peritoneal macrophages with LTB(4) induced the time- and concentration-dependent production of NO. In addition, low concentrations of LTB(4) acted in synergy with IFN-gamma to induce NO production. The NO produced mediated LTB(4)-induced microbicidal activity in macrophages, as demonstrated by the inhibitory effects of an inducible NO synthase inhibitor. LTB(4)-induced NO production and parasite killing were LTB(4) receptor dependent and were partially blocked by a PAF receptor antagonist. LTB(4) also induced significant tumor necrosis factor alpha (TNF-alpha) production, and blockade of TNF-alpha suppressed LTB(4)-induced NO release and parasite killing. A blockade of LTB(4) or PAF receptors partially inhibited IFN-gamma-induced NO and TNF-alpha production but not parasite killing. Finally, daily treatment of infected mice with CP-105,696 was accompanied by a significantly higher level of blood parasitemia, but not lethality, than that seen in vehicle-treated animals. In conclusion, our results suggest a role for LTB(4) during experimental T. cruzi infection. Chemoattractant molecules such as LTB(4) not only may play a major role in leukocyte migration into sites of inflammation in vivo but also, in the event of an infection, may play a relevant role in the activation of recruited leukocytes to kill the invading microorganism in an NO-dependent manner.

Topics: Animals; Benzopyrans; Carboxylic Acids; Cells, Cultured; Chagas Disease; Disease Models, Animal; Female; Immunity, Innate; Interferon-gamma; Leukotriene B4; Macrophage Activation; Macrophages, Peritoneal; Mice; Mice, Inbred BALB C; Nitric Oxide; Platelet Activating Factor; Receptors, Leukotriene B4; Time Factors; Trypanosoma cruzi; Tumor Necrosis Factor-alpha

Lipoxins and 15-epi-lipoxins are counter-regulatory lipid mediators that modulate leukocyte trafficking and promote the resolution of inflammation. To assess the potential of lipoxins as novel anti-inflammatory agents, a stable 15-epi-lipoxin A(4) analog, 15-epi-16-p-fluorophenoxy-lipoxin A(4) methyl ester (ATLa), was synthesized by total organic synthesis and examined for efficacy relative to a potent leukotriene B(4) (LTB(4)) receptor antagonist (LTB(4)R-Ant) and the clinically used topical glucocorticoid methylprednisolone aceponate. In vitro, ATLa was 100-fold more potent than LTB(4)R-Ant for inhibiting neutrophil chemotaxis and trans-epithelial cell migration induced by fMLP, but was approximately 10-fold less potent than the LTB(4)R-Ant in blocking responses to LTB(4). A broad panel of cutaneous inflammation models that display pathological aspects of psoriasis, atopic dermatitis, and allergic contact dermatitis was used to directly compare the topical efficacy of ATLa with that of LTB(4)R-Ant and methylprednisolone aceponate. ATLa was efficacious in all models tested: LTB(4)/Iloprost-, calcium ionophore-, croton oil-, and mezerein-induced inflammation and trimellitic anhydride-induced allergic delayed-type hypersensitivity. ATLa was efficacious in mouse and guinea pig skin inflammation models, exhibiting dose-dependent effects on edema, neutrophil or eosinophil infiltration, and epidermal hyperproliferation. We conclude that the LXA(4) and aspirin-triggered LXA(4) pathways play key anti-inflammatory roles in vivo. Moreover, these results suggest that ATLa and related LXA(4) analogs may have broad therapeutic potential in inflammatory disorders and could provide an alternative to corticosteroids in certain clinical settings.

Topics: Administration, Cutaneous; Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Calcimycin; Cell Movement; Chemotaxis, Leukocyte; Croton Oil; Disease Models, Animal; Diterpenes; Female; Guinea Pigs; Humans; Hydroxyeicosatetraenoic Acids; Hypersensitivity, Delayed; Iloprost; Inflammation; Leukotriene B4; Lipoxins; Mice; Phthalic Anhydrides; Skin; Terpenes

Perfluorocarbons have been shown to reduce the inflammatory process generated by alveolar macrophages in vitro. The aim of this study was to evaluate the impact of different ventilator modalities such as partial liquid ventilation (PLV), conventional ventilation (CV), and high-frequency oscillatory ventilation (HFOV) on the release of inflammatory mediators in vivo. Acute lung injury was induced in 30 male piglets by repeated saline lavage (arterial oxygen tension, <60 mm Hg; fraction of inspired oxygen, 1.0). Thereafter, animals were randomly assigned to one of five groups of six animals each: 1) 24 h of CV; 2) 24 h of CV plus surfactant therapy (S+CV); 3) 24 h of HFOV plus surfactant therapy (S+HFOV); 4) 1 h of PLV followed by 23 h of CV (PLV); and 5) 24 h of CV without previous lung injury (control group). Piglets randomized to S+CV or S+HFOV received natural surfactant (100 mg/kg). PLV with FC-77 was started in an initial dose of 30 mL/kg over 30 min followed by 0.5 mL x kg(-1) x min(-1) for another 30 min. After 1 h of PLV the animals were conventionally ventilated for 23 h. Before acute lung injury and after 24 h the number of inflammatory cells and the levels of IL-6, leukotriene B4, and tumor necrosis factor-alpha were measured in the bronchoalveolar lavage fluid. Additionally, the oxygenation index and the histopathologic damage were evaluated. Before acute lung injury, the number of inflammatory cells and the levels of mediators in bronchoalveolar lavage fluid were not different among the groups. After 24 h, the number of granulocytes in the PLV group was as low as in the control group. leukotriene B4 and IL-6 levels were found to be elevated in all groups except the control group (p < 0.01). The release of leukotriene B4 and IL-6 was lowest in the PLV group when compared with S+HFOV, S+CV, or CV (p < 0.05). No differences among the groups were detected for tumor necrosis factor-alpha. Although the concentrations of leukotriene B4 and IL-6 after PLV were lowest in the PLV group, histopathologic evidence of damage and the oxygenation index in the PLV group did not differ from that found in the S+CV or S+HFOV groups. In conclusion, PLV with perfluorocarbons may protect the lung from acute pulmonary inflammation more effectively than CV or HFOV does.

Topics: Animals; Animals, Newborn; Bronchoalveolar Lavage; Disease Models, Animal; Fluorocarbons; Interleukin-6; Leukotriene B4; Liquid Ventilation; Lung; Lung Injury; Male; Pulmonary Surfactants; Random Allocation; Swine; Tumor Necrosis Factor-alpha

Few techniques today enable us to measure the complex processes taking place inside a burn wound in vivo. The present in vivo technique was based on a standardised burn model in rat skin. A partial- or full-thickness burn was induced and resulted in a gelatinous oedema located between the skin and the underlying rectus muscle. The oedema has distinct borders to the surrounding connective tissue and is separated and removed easily for further analysis. Myeloperoxidase (MPO) activity used as indicator of neutrofil infiltration was increased significantly in the burn oedema versus non-burned skin. Leukocyte metabolic activity was high as shown by significantly higher free radical formation (ESR) in the oedema than in surrounding burned and non-burned tissue. Leukocyte viability measured by Trypan blue stain was 70% in the oedema of full-thickness burns. In order to decide whether processes taking place in the oedema communicate freely with systemic circulation, we conducted a number of experiments. Results show in burned animals in vivo that intravenous administration of indomethacin induced a strong inhibition of PGE(2) in the burn oedema as compared with saline but, as expected, had no significant effect on LTB(4) synthesis. In conclusion, the present technique allows us to analyse the processes taking place inside the burn wound in vivo and to evaluate the effects of various agents on these processes.

Topics: Albumins; Animals; Anti-Inflammatory Agents, Non-Steroidal; Burns; Dinoprostone; Disease Models, Animal; Edema; Evans Blue; Indomethacin; Leukotriene B4; Male; Neutrophils; Peroxidase; Rats; Rats, Sprague-Dawley

Although clinical evidence has suggested that dysregulated fatty acid metabolism is associated with atopic disorders, the molecular basis for such a correlation remains to be demonstrated. In the present study, we analyzed the fatty acid composition in peripheral blood cells of NC/Nga mice, a model for atopic dermatitis (AD). We found that arachidonic acid significantly accumulated in mice with the AD manifestation. In addition, the leucotriene B4-releasing ability upon calcium ionophore A23187 stimulation was potentiated in blood cells. An arachidonic acid accumulation was not apparent in the non-atopic BALB/c strain, but was still observed in healthy NC/Nga mice fed under specific pathogen-free conditions. These results indicate that a disturbed fatty acid metabolism in NC/Nga mice was not a trigger factor for their dermatitis development.

Topics: alpha-Linolenic Acid; Animals; Arachidonic Acid; Blood Cells; Calcimycin; Dermatitis, Atopic; Disease Models, Animal; Fatty Acids; Humans; In Vitro Techniques; Ionophores; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Mice, Mutant Strains

Cigarette smoking is closely related to the development and recurrence of inflammatory bowel disease (IBD). The present study aimed to investigate the underlying mechanisms of the adverse action of cigarette smoke (CS) exposure on trinitrobenzene sulfonic acid (TNBS)-induced IBD.. Rats were preexposed to CS once daily for 4 days before receiving a TNBS enema, and they were killed 24 h afterwards. The colonic myeloperoxidase (MPO) and xanthine oxidase (XO) activities, leukotriene B(4) (LTB(4)) and glutathione (GSH) levels, as well as the production of reactive oxygen metabolites (ROMs) were measured.. CS preexposure significantly augmented the adverse effects of the TNBS enema on colonic damage and increase in MPO activity, while it did not significantly alter the XO activity. Meanwhile, the elevation of ROM production and LTB(4) concentration in colonic tissues after the TNBS enema was also markedly enhanced by CS exposure. In contrast, the depressive action of the TNBS enema on cellular antioxidant GSH levels was reduced further by CS exposure. Pretreatment with a specific LTB(4) antagonist, ONO-4057, protected against colonic damage, particularly in the CS group.. CS exposure aggravated experimental IBD. This adverse action could be due to the depletion of GSH together with overproduction of LTB(4), followed by the accumulation of neutrophils and ROMs in the colonic tissue.

Topics: Analysis of Variance; Animals; Biomarkers; Colitis, Ulcerative; Disease Models, Animal; Glutathione; Intestinal Mucosa; Leukotriene B4; Luminescent Measurements; Male; Peroxidase; Probability; Rats; Rats, Sprague-Dawley; Risk Assessment; Sensitivity and Specificity; Tobacco Smoke Pollution; Xanthine Oxidase

Biologically active substances, such as prostaglandins, thromboxanes, and leukotrienes, which are metabolites involved in the arachidonic acid cascade, are detected in herniated disc samples obtained from patients with lumbar disc herniation. However, little is known concerning the relationships between these substances and clinical symptoms such as radicular pain. Thromboxane A2 (TXA2) induces not only potent platelet aggregation, but also blood vessel contraction. Leukotriene B4 (LTB4), a potent chemotactic agent, plays a role in inflammatory reactions by recruiting neutrophils and lymphocytes. The purpose of this study was to examine the roles of TXA2 and LTB4 in the hyperalgesia induced by application of nucleus pulposus to the lumbar nerve root in the rat. TXA2 synthetase inhibitor and LTB4 receptor antagonist, which were injected into the epidural space, decreased mechanical hyperalgesia at both three and seven days after epidural injection. There were no significant differences in sensitivity to noxious thermal stimuli following application of the nucleus pulposus or an epidural injection. Epidural injection of LTB4 receptor antagonist and/or TXA2 synthetase inhibitor may attenuate the painful radiculopathy due to lumbar disc herniation. In conclusion, our findings suggest that TXA2 and LTB4 may play significant roles in mechanical hyperalgesia induced by autologous nucleus pulposus.

Topics: Animals; Disease Models, Animal; Enzyme Inhibitors; Hyperalgesia; Intervertebral Disc Displacement; Leukotriene B4; Male; Methacrylates; Motor Activity; Phenylpropionates; Rats; Rats, Sprague-Dawley; Receptors, Leukotriene B4; Shoulder Pain; Thromboxane A2; Thromboxane-A Synthase

To summarize the physicochemical characterization, pharmacokinetic behavior, and biological evaluation of P792, a new monogadolinated MRI blood-pool agent.. The molecular modeling of P792 was described. The r1 relaxivity properties of P792 were measured in water and 4% human serum albumin at different magnetic fields (20, 40, 60 MHz). The stability of the gadolinium complex was assessed. The pharmacokinetic and biodistribution profiles were studied in rabbits. Renal tolerance in dehydrated rats undergoing selective intrarenal injection was evaluated. Hemodynamic safety in rats and in vitro histamine and leukotriene B4 release were also tested.. The mean diameter of P792 is 50.5 A and the r1 relaxivity of this monogadolinium contrast agent is 29 L x mmol(-1) x s(-1) at 60 MHz. The stability of the gadolinium complex in transmetallation is excellent. The pharmacokinetic and biodistribution profiles are consistent with that of a rapid-clearance blood-pool agent: P792 is mainly excreted by glomerular filtration, and its diffusion across normal endothelium is limited. Renal and hemodynamic safety is comparable to that of the nonspecific agent gadolinium-tetraazacyclododecane tetraacetic acid. No histamine or leukotriene B4 release was found in RBL-2H3 isolated mastocytes.. The relaxivity of P792 at clinical field is very high for a monogadolinium complex without protein binding. The pharmacokinetic and biodistribution profiles are consistent with those of a rapid-clearance blood-pool agent. Its initial safety profile is satisfactory. Experimental and clinical studies are underway to confirm the potential of P792 in MRI.

Topics: Acute Kidney Injury; Animals; Contrast Media; Disease Models, Animal; Hemodynamics; Heterocyclic Compounds; Histamine; Leukotriene B4; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Molecular Structure; Organometallic Compounds; Rabbits; Rats; Tissue Distribution

We have developed a new experimental ulcerative colitis model in rats. Topical pathological change of a round or a ellips shape was induced by subserosal injection of acetic acid (20%, 0.02 ml) into the middle colon of rats. The size of the induced ulcer could directly be measured using a caliper gauge, and the result was expressed as the ulcer area (mm2). We determined the concentration of leukotriene B4 (LTB4), which is one of important clinical factors, in the ulcer region and found that the quantity of LTB4 was well correlated with the size of the ulcer area. Histopathological studies of the ulcer region demonstrated that there were some morphological similarities to the human form of ulcerative colitis, characterized by edema, necrosis, inflammatory cell infiltration, crypt abscess and granulation tissue formation. Effects of 5-aminosalicylic acid and sodium prednisolone phosphate were investigated by intrarectal administration in this colitis model. The predominant improvement of colitis was obtained from both treatments in the ranges of the clinical doses of each drug. In conclusion, we suggest that this colitis model provides a new way for quantitative evaluation of the efficacy of new therapeutic agents for ulcerative colitis.

Topics: Acetic Acid; Animals; Anti-Inflammatory Agents; Colitis, Ulcerative; Disease Models, Animal; Inflammation Mediators; Leukotriene B4; Male; Mesalamine; Prednisolone; Rats; Rats, Wistar

This work studied the effects of hydrocortisone treatment in experimental acute pancreatitis on cytokines, phospholipase A2, and breakdown products of arachidonic acid and survival. Edematous and necrotizing pancreatitis were induced in Wistar rats by cerulein hyperstimulation and retrograde intraductal infusion of sodium taurocholate, respectively. Hydrocortisone (10 mg/kg) was administered intravenously 10 minutes after induction of acute pancreatitis. Serum was assayed for phospholipase A2; interleukin (IL) 1beta, IL-6, IL-10, thromboxane B2; Prostaglandin E2; and leukotriene B4 at five different time points. A significant release of inflammatory mediators was seen only in the severe model. Hydrocortisone powerfully suppressed arachidonic acid breakdown products and only mildly attenuated the systemic increase of phospholipase A2 and pro- and antiinflammatory cytokines. The mortality rate after 72 hr in the severe model was 86%. Hydrocortisone treatment reduced mortality to 13% (P = 0.001; Fisher's exact test). Hydrocortisone seems to be effective in the treatment of the early systemic inflammatory response syndrome associated with severe acute pancreatitis.

Topics: Acute Disease; Animals; Anti-Inflammatory Agents; Cytokines; Dinoprostone; Disease Models, Animal; Female; Hydrocortisone; Leukotriene B4; Pancreatitis; Rats; Rats, Wistar; Systemic Inflammatory Response Syndrome; Thromboxane B2

Bacterial lipopolysaccharide (LPS) is a risk factor for exacerbation of asthma and causes airway inflammation. The aim of this study was to examine the effects of disruption of prostaglandin (PG) H synthase (PGHS)-1 and PGHS-2 genes on pulmonary responses to inhaled LPS. PGHS-1(-/-), PGHS-2(-/-), and wild-type (WT) mice were exposed to 4 to 6 microg/m(3) LPS via aerosol. Enhanced pause (PenH), a measure of bronchoconstriction, was assessed using a whole-body plethysmograph before and immediately after a 4-h LPS exposure. Bronchoalveolar lavage (BAL) was performed after LPS exposure to assess inflammatory cells, cytokines/chemokines (tumor necrosis factor-alpha, interleukin-6, and macrophage inflammatory protein-2), and PGE(2). The degree of lung inflammation was scored on hematoxylin-and-eosin-stained sections. PGHS-1 and PGHS-2 protein levels were determined by immunoblotting. All mice exhibited increased PenH and methacholine responsiveness after LPS exposure; however, these changes were much more pronounced in PGHS-1(-/-) and PGHS-2(-/-) mice relative to WT mice (P < 0.05). There were no significant differences in inflammation as assessed by BAL fluid (BALF) cells or lung histology between the genotypes despite reduced BALF cytokines/chemokines and PGE(2) in PGHS-1(-/-) and PGHS-2(-/-) mice relative to WT mice (P < 0.05). PGHS-2 was upregulated more in PGHS-1(-/-) mice compared with WT mice after LPS exposure. We conclude that: (1) airway inflammation and hyperresponsiveness are dissociated in PGHS-1(-/-) and PGHS-2(-/-) mice exposed to LPS; (2) the balance of PGHS-1 and PGHS-2 is important in regulating the functional respiratory responses to inhaled LPS; and (3) neither PGHS-1 nor PGHS-2 is important in regulating basal lung function or the inflammatory responses of the lung to inhaled LPS.

Topics: Administration, Inhalation; Animals; Bronchoalveolar Lavage Fluid; Chemokines; Cyclooxygenase 1; Cyclooxygenase 2; Cytokines; Dinoprostone; Disease Models, Animal; Female; Isoenzymes; Leukotriene B4; Lipopolysaccharides; Lung; Male; Membrane Proteins; Mice; Mice, Inbred Strains; Mice, Mutant Strains; Pneumonia; Prostaglandin-Endoperoxide Synthases; Proteins; Up-Regulation

Morin, a bioflavonoid with antioxidant properties, shows intestinal anti-inflammatory activity in the acute phase of the trinitrobenzenesulphonic acid model of rat colitis.. To assess the anti-inflammatory activity of morin in the chronic stages of trinitrobenzenesulphonic acid-induced rat colitis.. Rats were rendered colitic by a single colonic instillation of 30 mg of the hapten trinitrobenzenesulphonic acid dissolved in 0.25 mL of 50% ethanol. A group of colitic animals was given morin orally at doses of 25 mg/kg daily. Animals were sacrificed every week for 4 weeks. Colonic damage was evaluated macroscopically and microscopically. Different biochemical markers of colonic inflammation were also assayed, including myeloperoxidase activity, leukotriene B4 and interleukin-1beta synthesis, glutathione and malonyldialdehyde levels and nitric oxide synthase activity.. The administration of morin facilitated tissue recovery during the 4 weeks following colonic insult with trinitrobenzenesulphonic acid, as demonstrated macroscopically and microscopically, as well as biochemically by a reduction in myeloperoxidase activity. The intestinal anti-inflammatory effect of morin was accompanied by a significant reduction in colonic leukotriene B4 and interleukin-1beta levels, improvement in colonic oxidative stress and inhibition of colonic nitric oxide synthase activity.. Morin exerts a beneficial anti-inflammatory effect in the chronic phase of trinitrobenzenesulphonic acid-induced rat colitis through the down-regulation of some of the mediators involved in the intestinal inflammatory response, including free radicals, cytokines, leukotriene B4 and nitric oxide.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Chronic Disease; Colitis; Disease Models, Animal; Female; Flavonoids; Interleukin-1; Intestinal Mucosa; Leukotriene B4; Nitric Oxide; Nitric Oxide Synthase; Peroxidase; Rats; Rats, Wistar; Trinitrobenzenesulfonic Acid

Topics: Animals; Biomarkers; Disease Models, Animal; Humans; Leukotriene B4; Prognosis; Respiratory Distress Syndrome

A murine model (C3H mice) of squamous cell carcinoma (SCCVII) has been used to investigate the role of arachidonic acid (AA) metabolites in head and neck cancer. Inhibition of tumor growth by cyclooxygenase (COX) and lipoxygenase (LOX) inhibitors of AA metabolism has been associated with changes in levels of AA metabolites in tumor tissues and inflammatory cell infiltrates. To characterize this model further, the effects of exogenous AA metabolites on tumor growth in vitro and in vivo were investigated.. Following subcutaneous inoculation with SCCVII tumor cells, control (16 mice) and treatment (24 mice) groups were injected with peritumoral vehicle or AA metabolite. Peritumoral injections of prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and 12-hydroxyeicosatetraenoic acid (12-HETE) were performed for 16-21 days, and final excised tumor weights were measured. In vitro production of PGE2 and LTB4 was assayed in 2-5 day cultures of SCCVII. Exogenous PGE2 effects on tumor cell growth was assessed with the MTT assay in vitro.. Tumor growth was significantly inhibited (p =.03) following peritumoral injection of PGE2. Final tumor weights were not affected by LTB4 or 12-HETE. Tumor inhibition by PGE2 was associated with increased tumor tissue levels of LTB4 (p =.04). In vitro, SCCVII produced minimal amounts of PGE2 and LTB4, and PGE2 had minimal effect on growth.. In this model, tumor inhibition by exogenous PGE2 is primarily mediated by affecting host-tumor interactions, although there may be some direct effect on tumor cells. Changes in tumor tissue levels of LTB4 following peritumoral PGE2 administration may be attributable to negative feedback inhibition of the COX pathway with shunting into the LOX pathway. SCCVII cells are probably not a significant source of prostaglandins and leukotrienes in vivo. These data provide insight into the mechanism of action of inhibitors of AA metabolism on tumor growth.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Arachidonic Acids; Carcinoma, Squamous Cell; Cell Division; Cells, Cultured; Dinoprostone; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Head and Neck Neoplasms; Injections, Intralesional; Leukotriene B4; Mice; Mice, Inbred C3H; Reference Values

The pathophysiology of enterohaemorrhagic Escherichia coli (EHEC) infection remains unclear. Eicosanoids have been implicated as pathophysiological mediators in other colitides.. To determine if prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) contribute to mucosal inflammation and dysfunction in EHEC colitis.. Ten day old rabbits were infected with EHEC. For five days after infection, mucosal synthesis of PGE(2) and LTB(4) was measured in distal colonic tissue from control and infected animals and (51)Cr-EDTA permeability was assessed in vivo. Myeloperoxidase activity was measured and histological inflammation and damage were assessed at five days in control and infected animals and after treatment of infected animals with the LTB(4) synthesis inhibitor MK-886. In separate experiments, ion transport was measured in Ussing chambers, before and after in vitro addition of the cyclooxygenase inhibitor indomethacin.. LTB(4) synthesis was increased from day 2 after infection onwards and PGE(2) synthesis was increased on day 3. Mucosal permeability did not increase until day 5 after infection. MK-886 inhibited colonic LTB(4) production but did not reduce diarrhoea, inflammation, or mucosal damage. Electrolyte transport was not significantly altered on day 3 after infection. However, both Cl secretion and reduced Na absorption found on day 5 were partially reversed by indomethacin.. Tissue synthesis of PGE(2) and LTB(4) did not correlate temporally with EHEC induced inflammation or changes in mucosal permeability and ion transport. Cyclooxygenase inhibition partially reversed ion transport abnormalities but lipoxygenase inhibition did not affect mucosal inflammation or histological damage. We conclude that the contribution of eicosanoids to mucosal injury and dysfunction is more complex than previously suggested.

Topics: Animals; Colitis; Dinoprostone; Disease Models, Animal; Eicosanoids; Electrolytes; Escherichia coli Infections; Gastric Mucosa; Gastrointestinal Hemorrhage; Indoles; Leukotriene B4; Lipoxygenase Inhibitors; Permeability; Rabbits

Leukotriene B(4) (LTB(4)) is a potent chemoattractant active on multiple leukocytes, including neutrophils, macrophages, and eosinophils, and is implicated in the pathogenesis of a variety of inflammatory processes. A seven transmembrane-spanning, G protein-coupled receptor, called BLTR (LTB(4) receptor), has recently been identified as an LTB(4) receptor. To determine if BLTR is the sole receptor mediating LTB(4)-induced leukocyte activation and to determine the role of LTB(4) and BLTR in regulating leukocyte function in inflammation in vivo, we generated a BLTR-deficient mouse by targeted gene disruption. This mouse reveals that BLTR alone is responsible for LTB(4)-mediated leukocyte calcium flux, chemotaxis, and firm adhesion to endothelium in vivo. Furthermore, despite the apparent functional redundancy with other chemoattractant-receptor pairs in vitro, LTB(4) and BLTR play an important role in the recruitment and/or retention of leukocytes, particularly eosinophils, to the inflamed peritoneum in vivo. These studies demonstrate that BLTR is the key receptor that mediates LTB(4)-induced leukocyte activation and establishes a model to decipher the functional roles of BLTR and LTB(4) in vivo.

Topics: Animals; Calcium; Cell Adhesion; Chemotactic Factors; Chemotaxis, Leukocyte; Disease Models, Animal; Eosinophils; Gene Targeting; Leukotriene B4; Macrophages, Peritoneal; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscles; Neutrophils; Peritonitis; Receptors, Leukotriene B4; Thioglycolates; Venules

Phospholipase D (PLD) hydrolyzes phosphatidylcholine and produces lipid second messengers. Although cellular PLD has recently been recognized as an important signal-transmitting enzyme, the role of PLD in pathophysiologic conditions is largely unknown. In particular, the regulation of PLD in intestinal inflammation has not been previously investigated. The aim of the present study was to elucidate the role of PLD in experimental colitis.. Rats were intracolonically administered acetic acid and assessed for mucosal damage, mucosal PLD activity, mucosal myeloperoxidase activity, mucosal chemiluminescence and luminal concentration of leukotriene B4. Acetic acid treatment induced acute mucosal injury that was maximal at 24 h after treatment.. Mucosal PLD activity was significantly elevated and correlated with mucosal damage. Chemiluminescence in colitic mucosa was inhibited by the addition of ethanol which suppresses the formation of phosphatidic acid catalyzed by PLD.. These results suggest that PLD is activated in experimental colitis in rats and that PLD may play a role in mucosal damage induced by reactive oxygen metabolites.

Topics: Acetates; Acute Disease; Animals; Central Nervous System Depressants; Colitis; Colon; Data Interpretation, Statistical; Disease Models, Animal; Enzyme Activation; Ethanol; Female; Immunoenzyme Techniques; Intestinal Mucosa; Leukotriene B4; Luminescent Measurements; Peroxidase; Phospholipase D; Phospholipids; Rats; Rats, Wistar; Time Factors

We investigated the role of leukotriene B4 (LTB4) in murine arthritis models using a leukotriene A4 (LTA4) hydrolase inhibitor, SA6541. SA6541 inhibited the severity of collagen-induced arthritis and muramyl dipeptide (MDP)-induced hyperproliferation of synovial cells in vivo. SA6541 also inhibited LTA4-induced hyperproliferation of synovial stromal cells in vitro. These results suggest that LTB4 may play an important role in arthritis models.

Topics: Acetylmuramyl-Alanyl-Isoglutamine; Aniline Compounds; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis; Body Weight; Bone and Bones; Cell Division; Cell Survival; Collagen; Cysteine; Disease Models, Animal; Epoxide Hydrolases; Female; Leukotriene B4; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Prednisolone; Stromal Cells; Synovial Fluid; Tarsus, Animal

It has been suggested that multiple sublethal insults are commonly associated with the development of multiple organ failure (MOF). The gut is considered to be pivotal in the pathogenesis of MOF. This study investigated the effects of repeated ischemia-reperfusion of the rat small intestine.. Groups of rats underwent 30 min of superior mesenteric artery occlusion or sham operation followed by 24 h of reperfusion. They then received an additional 30 min of superior mesenteric artery occlusion and 2 h of reperfusion or sham operation. Small intestine was examined for mucosal injury, neutrophil infiltration, goblet cell number, and generation of the eicosanoids, prostaglandin E2, and leukotriene B4. Activation of neutrophils was assessed in systemic venous blood.. Animals subjected to two insults of ischemia-reperfusion demonstrated significantly less mucosal injury than animals undergoing one episode of ischemia and 2 h of reperfusion, despite increased neutrophil infiltration, leukotriene B4, and activated systemic neutrophils. Goblet cell number was elevated in animals 24 h after the first ischemia-reperfusion insult and remained enhanced after the second episode of ischemia-reperfusion.. The initial episode of ischemia-reperfusion caused an adaptive response associated with cytoarchitectural preservation following the subsequent insult. Increased mucus production was associated with mucosal protection. Nevertheless, repeated ischemia-reperfusion potentiated the local inflammatory response and the systemic activation of neutrophils.

Topics: Animals; Dinoprostone; Disease Models, Animal; Inflammation; Intestinal Mucosa; Intestine, Small; Leukotriene B4; Male; Multiple Organ Failure; Neutrophil Activation; Rats; Rats, Sprague-Dawley; Recurrence; Reperfusion Injury

We examined the effect of soluble complement receptor type 1 (sCR1) on mucosal injury and inflammation in a rat model of ischemia/reperfusion. Groups of vehicle- and sCR1-treated rats underwent 30 min of mesenteric ischemia followed by 60 or 120 min of reperfusion. When compared to vehicle-treated rats, treatment with sCR1 (12 mg/kg) prior to 120 min of reperfusion significantly reduced mucosal injury, neutrophil infiltration, leukotriene B4 production, and restored villus height to control levels. The protective effect of sCR1 evident at 120 min of reperfusion was not observed at 60 min of reperfusion despite rapid inactivation of complement. These data suggest that complement inhibition minimized mucosal disruption by facilitating mucosal restitution or interrupting the inflammatory process. Delayed administration of sCR1 for 30 or 60 min into the reperfusion period progressively reduced the protection. sCR1-mediated rapid recovery of rat intestine after ischemia/reperfusion underscores the fundamental role of complement activation in neutrophil-mediated tissue injury.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Complement Activation; Disease Models, Animal; Hemodynamics; Intestinal Mucosa; Intestine, Small; Leukotriene B4; Male; Neutrophils; Rats; Rats, Sprague-Dawley; Receptors, Complement 3b; Reperfusion Injury; Solubility

To investigate the role of eicosanoid generation and neutrophilic infiltration in the protective effects of U74389F against ischemia/reperfusion injury in the small intestines of rats.. Prospective, randomized, controlled study.. University research laboratory.. Adult, male Sprague-Dawley rats weighing between 200 and 300 g.. Groups (5-8) of rats treated with U74389F or vehicle were subjected to a sham operation and 30 mins of ischemia by occlusion of the superior mesenteric artery or 30 mins of ischemia followed by 60 or 120 mins of reperfusion. U74389F (2.5 mg/kg i.v.) or vehicle (citrate buffer) were slowly injected 2 mins before ischemia.. Ischemia significantly (p < .05) increased mucosal injury (0 [normal] to 5) in both U74389F and untreated rats. In contrast, U74389F significantly (p < .05) attenuated the severity of injury after reperfusion. In vehicle-treated rats, ischemia/reperfusion significantly reduced villus height in both U74389F and untreated groups. However, the surface epithelial layer was intact in the U74389F but not in the vehicle-treated group. In addition, compared with the vehicle-treated group, U74389F significantly reduced neutrophil infiltration and prevented the increase in leukotriene B4 and prostaglandin E2 in response to ischemia and reperfusion.. This study demonstrates that the mechanism of U74389F against mesenteric ischemia/reperfusion includes a delay and reduction of neutrophilic infiltrate, an inhibition of leukotriene B4 production, and a facilitation of mucosal restitution.

Topics: Animals; Antioxidants; Dinoprostone; Disease Models, Animal; Drug Evaluation, Preclinical; Eicosanoids; Immunosuppressive Agents; Inflammation; Injections, Intravenous; Intestine, Small; Leukotriene B4; Male; Neutrophil Activation; Pregnatrienes; Prospective Studies; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury

In glomerulonephritis there is co-activation of the arachidonic acid cyclooxygenase pathway toward synthesis of prostaglandins (PG) and thromboxane (Tx) and of lipoxypenase pathways toward synthesis of hydroxyeicosatetraenoic acids (HETEs) and leukotrienes (LTs). Cyclooxygenase inhibition with non-steroidal anti-inflammatory drugs results in enhanced glomerular LT synthesis with potentially adverse effects on the severity of the inflammation. The effect of Tx inhibition or antagonism on LT synthesis is unknown. Because TxA2 is the most abundant eicosanoid synthesized in nephritic glomeruli, and because TxA2 synthase inhibitors and receptor antagonists are now available for the treatment of glomerulonephritis, it becomes important to address this question. In this study we assessed the effect of a TxA2 synthase inhibitor, Dazmegrel, and a TxA2 receptor antagonist, SQ-29 548, on glomerular PGE2, LTB4, and 12-HETE synthesis in a model of mesangial nephritis induced in the rat by the administration of a monoclonal antibody against the Thy 1.1 antigen of rat mesangial cells. Dazmegrel, in doses sufficient to effectively block glomerular TxA2 synthesis, significantly increased 12-HETE and PGE2 synthesis without an effect on the synthesis of LTB4. SQ-29 548 had no effect on glomerular PGE2, LTB4, or 12-HETE production. Because PGE2 preserves kidney function in glomerulonephritis, and because 12-HETE inhibits 5-lipoxygenase, the enhanced PGE2 and 12-HETE production within nephritic glomeruli after TxA2 synthase inhibition may be a superior anti-inflammatory strategy when compared with TxA2 receptor antagonism.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Antilymphocyte Serum; Bridged Bicyclo Compounds, Heterocyclic; Dinoprostone; Disease Models, Animal; Fatty Acids, Unsaturated; Glomerulonephritis, Membranoproliferative; Hydrazines; Kidney Glomerulus; Leukotriene B4; Macrophages; Rats; Rats, Wistar; Thromboxane A2; Thromboxane-A Synthase; Thy-1 Antigens

It has been reported that zinc sulphate contributes an anti-inflammatory action in many animal models; however, the impact of zinc in colitis remains unclear. The aim of the present study was to examine the role of zinc sulphate in experimental colitis.. Colitis was induced by 2,4,6-trinitrobenzenesulphonic acid (TNB) in rats. Beginning at the first day of TNB colitis, the rats were treated with a zinc sulphate enema once daily for 6 days. The rats were examined 8 days later.. The TNB induced severe colitis as evidenced by increased mucosal lesion area, mucosal myeloperoxidase (MPO) activity and prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. Six days after the application of the zinc sulphate enema, the mucosal lesion area, MPO activity, PGE2 and LTB4 levels all decreased significantly. Mucosal superoxide dismutase activity remained unchanged after zinc treatments.. Our data suggest that zinc sulphate enemas have an anti-inflammatory action on experimental colitis.

Topics: Animals; Colitis; Dinoprostone; Disease Models, Animal; Enema; Female; Intestinal Mucosa; Leukotriene B4; Peroxidase; Rats; Rats, Sprague-Dawley; Superoxide Dismutase; Zinc Sulfate

It is important to develop an appropriate animal model for further investigation into inflammatory bowel disease (IBD). We therefore investigated a trinitrobenzene sulfonic acid (TNBS) ileitis model. Dietary fat in Crohn's disease is still a controversial risk factor for IBD. We therefore also studied the effects of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT) on TNBS ileitis.. An intraileal injection of TNBS induced ulceration and inflammation with thickening of the intestinal wall, which were characterized histologically by infiltration of polymorphic nuclear leucocytes and by granuloma formation. The mucosal damage score and serum sialic acid levels reached their highest 7 days after the TNBS injection and then gradually decreased. The mucosal damage series in the MCT group was significantly lower than in the LCT group, and levels of tumour necrosis factor-alpha (TNF-alpha) and leukotriene B4 (LTB4) tended to be lower in the MCT group.. These results suggested that TNBS enteritis might be useful as an IBD animal model and that MCT modulates intestinal inflammation and is less damaging than LCT.

Topics: Analysis of Variance; Animals; Disease Models, Animal; Ileitis; Immunoenzyme Techniques; Leukotriene B4; Male; Ornithine Decarboxylase; Prostaglandins E; Random Allocation; Rats; Rats, Sprague-Dawley; Statistics, Nonparametric; Triglycerides; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha

Topics: Acute Disease; Animals; Blood Platelets; Disease Models, Animal; In Vitro Techniques; Inflammation; Kinetics; Leukocyte Count; Leukocytes, Mononuclear; Leukotriene B4; Leukotriene E4; Male; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Platelet Count; Rabbits

The role of 5-lipoxygenase metabolites of arachidonic acid in the inflammatory response associated with experimental acute pancreatitis has been evaluated. For this purpose, an experimental necrohemorrhagic pancreatitis was induced in rats by intraductal administration of 5% sodium taurocholate. Neutrophil infiltration was detected in pancreas at 1 and 3 h after the induction of pancreatitis. This was concomitant with increased levels of leukotriene B4 and peptide leukotrienes (C4, D4 and E4). In lung, similar increases in neutrophil infiltration were detected but only 3 h after acute pancreatitis induction, and no changes in leukotriene B4 nor peptide leukotrienes were apparent at this time. These results suggest that after induction of acute pancreatitis, 5-lipoxygenase metabolites could play a role in the inflammatory response in the pancreas, but they are not involved in the inflammatory response in lung.

Topics: Acute Disease; Animals; Disease Models, Animal; Leukotriene B4; Leukotrienes; Lipase; Lung; Male; Neutrophils; Pancreas; Pancreatitis; Peroxidase; Rats; Rats, Wistar; Taurocholic Acid

The objective of this study was to establish and characterize the invasion of polymorphonuclear leukocytes (PMNs) into a normal cornea after intrastromal injection of the tripeptide chemoattractants generated from alkali-degraded corneas.. The following samples were injected into the midstroma of normal rabbit corneas: ultrafiltered tripeptide chemoattractants (N-acetyl-proline-glycine-proline and N-methyl-proline-glycine-proline) generated from alkali-degraded corneas, synthetic N-acetyl-PGP, positive control (leukotriene B4 [LTB4]), or negative control (Hanks' balanced salt solution [HBSS]). Timed responses of PMN infiltration were established for effective concentrations of LTB4 or the ultrafiltered chemoattractants.. All intrastromal injections resulted in the immediate development of an edematous disc that was 10 mm in diameter. The lesion essentially had cleared in the HBSS-injected eyes by 8 hours, and histologic sections revealed minimal numbers of PMNs in the cornea or limbal tissue. The injection of LTB4 or the ultrafiltered tripeptide chemoattractants induced peak numbers of PMNs within the stroma at 8 hours, subsiding by 16 hours. Seventy units of ultrafiltered chemoattractants yielded a strong PMN response, similar to 1 X 10(-5) M LTB4. The highest concentration of ultrafiltered chemoattractants (350 U) produced a severe PMN response that was characterized by a solid sheet of neutrophils surrounding the injection site. The injection of synthetic N-acetyl-PGP (2 X 10(-4) M) produced a marked PMN response.. PMN invasion of the normal cornea after the injection of the ultrafiltered tripeptide chemoattractants or the synthetic N-acetyl-PGP mimicked early PMN infiltration in the alkali-injured eye, confirming the importance of this chemoattractant as an inflammatory mediator.

Topics: Animals; Burns, Chemical; Chemotactic Factors; Chemotaxis, Leukocyte; Corneal Stroma; Disease Models, Animal; Eye Burns; Humans; Injections; Keratitis; Leukocyte Count; Leukotriene B4; Neutrophils; Oligopeptides; Rabbits; Sodium Hydroxide

Interleukin-10 (IL-10) is an anti-inflammatory cytokine that downregulates the secretion of pro-inflammatory cytokines and additionally induces the secretion of anti-inflammatory cytokines, thus possibly leading to reduction of chronic inflammation in inflammatory bowel disease. In this study we evaluated the anti-inflammatory effect of IL-10 in a model of acute colitis in rabbits.. Colitis was induced by rectal instillation of formalin, 0.65%, followed by intravenous infusion of 0.85 ml heat-aggregated rabbit immunoglobulin. Rabbits were treated with an intravenous bolus of recombinant human IL-10 (SCH52000), 100 microg/kg (n=14) or 500 microg/kg (n=14), 1 h before induction of colitis (control group, n=12).. High-dose IL-10 improved macroscopic scores of inflammation and decreased tissue myeloperoxidase levels and leukotriene B4 levels in dialysate fluid. Thromboxane B2 and prostaglandin E2 levels remained unaffected.. IL-10 ameliorates acute colitis in this model. Consequently, this anti-inflammatory cytokine may have a role in the therapy of acute inflammatory bowel disease.

Topics: Acute Disease; Animals; Antigen-Antibody Complex; Disease Models, Animal; Dose-Response Relationship, Drug; Down-Regulation; Enterocolitis; Interleukin-10; Intestinal Mucosa; Leukotriene B4; Male; Rabbits; Random Allocation; Reference Values

The flavonoid morin was tested for anti-inflammatory activity in trinitrobenzenesulfonic acid (TNBS)-induced rat colitis. Rats were pretreated orally with several doses of the flavonoid (5, 10, 25, 100 and 200 mg/kg) 48, 24 and 1 h before and 24 h after colitis induction and examined for colonic damage 48 h after colitis induction. Colonic inflammation was characterized by diffuse hemorrhagic necrosis of the mucosa, bowel wall thickening, impairment of fluid absorption, increase in myeloperoxidase (MPO) activity, enhanced leukotriene B4 (LTB4) synthesis, glutathione depletion and increased levels of malonyldialdehyde (MDA). Morin treatment, at doses ranging from 10 to 200 mg/kg, significantly reduced colonic macroscopic damage. This beneficial effect was also confirmed by inhibition of colonic MPO activity. Several mechanisms may contribute to the protective effect exerted by morin. First, inhibition of colonic LTB4 synthesis is a common feature for all the active doses of the flavonoid. Second, the antioxidant properties of morin, which partially prevented colonic glutathione depletion (at doses of 10 and 25 mg/kg) or inhibited colonic MDA production (at doses of 100 and 200 mg/kg), can collaborate in preventing TNBS-induced inflammation.

Topics: Acute Disease; Administration, Oral; Animals; Antioxidants; Colitis; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Flavonoids; Leukotriene B4; Malondialdehyde; Rats; Rats, Wistar; Trinitrobenzenesulfonic Acid

The movement of leukocytes into tissues is regulated by the local production of chemical mediators collectively referred to as chemoattractants. Although chemoattractants constitute a diverse array of molecules, including proteins, peptides, and lipids, they all appear to signal leukocytes through a related family of seven transmembrane-spanning G protein-coupled receptors. The eosinophil is a potent proinflammatory cell that is attracted into tissues during allergic inflammation, parasitic infection, and certain malignancies. Since the molecular mechanisms controlling eosinophil recruitment are incompletely understood, we performed a degenerate polymerase chain reaction on cDNA isolated from murine eosinophils to identify novel chemoattractant receptors. We report the isolation of a cDNA that encodes a 351-amino acid glycoprotein that is 78% identical to a human gene that has been reported to be a purinoceptor (P2Y7) and a leukotriene B4 (LTB4) receptor (BLTR). Chinese hamster ovary (CHO) cells transfected with this cDNA specifically bound [3H]LTB4 with a dissociation constant of 0.6 +/- 0.1 nM. Furthermore, LTB4 induced a dose-dependent intracellular calcium flux in transfected CHO cells. In contrast, [35S]dATP did not specifically bind to these transfectants. This mRNA was expressed at high levels in interleukin 5-exposed eosinophils, elicited peritoneal macrophages and neutrophils, and to a lesser extent interferon gamma stimulated macrophages. Low levels of expression were detected in the lung, lymph node, and spleen of unchallenged mice. Western blot analysis detected the mBLTR protein in murine eosinophils and alveolar macrophages as well as human eosinophils. In addition, elevated levels of mBLTR mRNA were found in the lungs of mice in a murine model of allergic pulmonary inflammation in a time course consistent with the influx of eosinophils. Our findings indicate that this murine receptor is an LTB4 receptor that is highly expressed on activated leukocytes, including eosinophils, and may play an important role in mediating eosinophil recruitment into inflammatory foci.

Topics: Amino Acid Sequence; Animals; Calcium; Cell Line; Chemotactic Factors, Eosinophil; CHO Cells; Cloning, Molecular; Cricetinae; Disease Models, Animal; DNA, Complementary; Eosinophils; Female; Humans; Leukotriene B4; Macrophages, Alveolar; Mice; Mice, Inbred Strains; Mice, Transgenic; Molecular Sequence Data; Plasmids; Protein Binding; Protein Biosynthesis; Receptors, Leukotriene B4; Respiratory Hypersensitivity; RNA, Messenger; Transfection; Tumor Cells, Cultured

An intrapleural injection of carrageenan in rats induced LTB4 and LTC4/D4/E4 biosynthesis, exudate formation, and cellular influx in the pleural cavity. An injection of calcium ionophore (A23187, 100 nmol) 16-18 h after carrageenan injection augmented leukotriene biosynthesis and exudate formation, but not cellular influx. The carrageenan-induced pleurisy model modifid by A23187 administration was used to study the oral effect of CGS 23885 (N-hydroxy-N-[(6-phenoxy-2H-1-benzopyran-3-yl)-methyl]urea), a potent 5-lipoxygenase (5-LO) inhibitor, on inflammatory parameters. CGS 23885 dose-dependently (1 to 30 mg/kg) inhibited the enhanced LTB4 and LTC4/D4/E4 (1 to 10 mg/kg) biosynthesis, but had no effect on enhanced exudate formation. An inhibitory effect of CGS 23885 of small magnitude on cellular influx due to carrageenan stimulation was seen at 30 mg/kg. The concentrations of CGS 23885 in the pleural fluid were dose-related, and a positive correlation (r2=0.989) between pleural fluid concentration of LTB4 and CGS 23885 was observed. The results confirm that CGS 23885 is a specific, orally active 5-LO inhibitor which can achieve concentrations in the pleural cavity sufficient to inhibit production of LTB4 and LTC4/D4/E4 in an ongoing inflammatory response.

Topics: Animals; Chromones; Disease Models, Animal; Dose-Response Relationship, Drug; Hydroxylamines; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Rats; Rats, Sprague-Dawley

There is crucial evidence that leukotrienes are significant mediators of inflammation in inflammatory bowel diseases (IBD). Thus, selective inhibition of leukotriene synthesis is believed to provide a novel approach to therapy of IBD. The aim of the study is to study the efficacy of a potent 5-lipoxygenase activating protein inhibitor (FLAP), BAY y 1015 in a dextran sulfate model of mouse colitis.. Outbred female mice weighing approximately 25 grams were used to produce acute or chronic colitis by feeding 5% dextran sulfate in drinking water.. Colitic mice were treated with placebo (3% starch suspension, 0.1 ml. p.o., bid) or BAY y 1015 at 8 or 24 mg/kg, p.o., bid or olsalazine, 150 mg/kg/day, p.o.. Efficacy was determined by measuring daily disease activity index (DAI), quantitative histological scores, qualitative histology and measurement of tissue myeloperoxidase (MPO) and leukotriene B4 (LTB4) levels.. BAY y 1015 was significantly more effective in improving the qualitative histology, inhibiting the DAI, inflammation scores (37-79%), crypt scores (28-71%), MPO (49-57%) and LTB4 levels (56-63%) compared to placebo treatment at all levels of colitis. The two doses of BAY y 1015 were equipotent in decreasing TLB4 levels. BAY y 1015 was significantly better than olsalazine in two of the three protocols used in this study. In the advanced disease level both doses of BAY y 1015 were equipotent in inhibiting crypt and (28-32%) inflammation scores (34-36%), LTB4 (34-56%) and MPO 41-49%) compared to olsalazine.. This study suggests the possibility of investigating the use of this compound for the treatment of human inflammatory bowel diseases.

Topics: Animals; Colitis; Dextran Sulfate; Disease Models, Animal; Female; Leukotriene B4; Lipoxygenase Inhibitors; Mice; Peroxidase; Quinolines

Nitric oxide (NO) synthase inhibitors, such as NG-nitro-L-arginine methyl ester (L-NAME), have been shown to attenuate endotoxin-induced uveitis (EIU) but they could increase leukocyte adhesion to the vascular endothelium. We hypothesize that a concomitant treatment with the 5-lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) in 50% dimethylsulfoxide (DMSO, a hydroxyl radical scavenger) could improve the anti-inflammatory activity of L-NAME. EIU was induced in albino rabbits by intravitreal injection of 100 ng lipopolysaccharide. Animals were treated with multiple intraperitoneal injections of 50% DMSO in phosphate-buffered saline (PBS), NDGA (10 mg/kg) in 50% DMSO, L-NAME (50 mg/ kg) in PBS, or the combination NDGA+L-NAME. Uveitis was assessed by slit lamp examination, protein levels in aqueous humor, and myeloperoxidase (MPO) activity in the iris/ciliary body 6 h after induction. Nitrite, leukotriene B4 (LTB4), prostaglandin E2 (PGE2), platelet-activating factor (PAF) and interleukin-1 beta (IL-1 beta) levels in aqueous humor were also determined. NDGA or L-NAME alone did not show a significant reduction of uveitis intensity, although a significant decrease in MPO or in proteins was found, respectively. The combination NDGA+L-NAME significantly reduced the uveitis intensity, MPO in the iris/ciliary body, and the levels of nitrites, LTB4, PGE2, and PAF in aqueous humor. IL-1 beta levels were lower than the detection limit of the radioimmunoassay in all treatment groups. We conclude that concomitant treatment with NDGA in DMSO improves the anti-inflammatory activity of L-NAME during the early phase of EIU, suggesting that the inhibition of NO synthesis could enhance leukocyte infiltration and the release of oxygen free radicals.

Topics: Administration, Topical; Animals; Anti-Inflammatory Agents; Aqueous Humor; Ciliary Body; Dimethyl Sulfoxide; Dinoprostone; Disease Models, Animal; Drug Therapy, Combination; Endothelium, Vascular; Endotoxins; Enzyme Inhibitors; Interleukin-1; Iris; Leukotriene B4; Lipoxygenase Inhibitors; Male; Masoprocol; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Peroxidase; Rabbits; Salmonella typhimurium; Treatment Outcome; Uveitis

Sterile perforated polyethylene spheres (wiffle golf balls) were implanted s.c. in beagle dogs. A local inflammatory reaction was elicited within the spheres by injecting carrageenan. Changes in leukocyte count, prostaglandin E2, thromboxane B2 and leukotriene B4 levels were monitored in fluid samples collected over a 24-hr period. Blood samples were also collected at various time points and analyzed for prostaglandin E2 and leukotriene B4 production after ex vivo calcium ionophore treatment. Effects of standard antiinflammatory agents (aspirin, indomethacin, dexamethasone, tenidap and zileuton) and newer cyclooxygenase-2 (COX-2) selective agents (nimesulide, nabumetone and SC-58125) were determined after oral administration. Ex vivo inhibition of cyclooxygenase product synthesis (prostaglandin E2, thromboxane B2) in whole blood was used as an indicator of activity for the constitutive COX-1 isoform, although inhibition of the synthesis of these mediators in the chamber exudate during an inflammatory process is believed to represent COX-2 inhibition. Treatment effects on leukotriene B4 production were also determined both ex vivo in whole blood and in the fluid. All of the compounds tested, except aspirin, inhibited leukocyte infiltration into the fluid exudate. Inhibitors that exert their effects on both isozymes of cyclooxygenase attenuate production of cyclooxygenase metabolites in both the inflammatory exudate and in peripheral blood ex vivo, although COX-2 selective inhibitors only demonstrated activity in the exudate. A 5-lipoxygenase inhibitor (zileuton), a corticosteroid (dexamethasone) and a dual COX-2 selective/5-lipoxygenase inhibitor (RWJ 63556) had similar profiles in that they all inhibited cell infiltration and eicosanoid production in the fluid and also attenuated leukotriene B4 production in both the fluid and blood.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Cyclooxygenase Inhibitors; Disease Models, Animal; Dogs; Evaluation Studies as Topic; Female; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Sulfonamides; Thiophenes

The kinetic profiles of leukotriene B4 (LTB4) and E4 (LTE4) after intravenous administration (30 nmol/kg) of the inflammatory peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) were evaluated in male rabbits. LTB4 and LTE4 reached the maximal concentration of 84.2 +/- 60.0 and 162.2 +/- 51.4 nmol/L (mean +/- s.d.), at 2 and 5 min, respectively. The first elimination phase for LTB4 and LTE4, after FMLP administration, showed an apparent half-life of 24.6 +/- 6.7 and 36.9 +/- 13.0 min, respectively. The area under the blood concentration-time curve (AUC, nmol min/L) of LTB4 and LTE4 was 2178 +/- 1591 and 7627 +/- 3052, respectively. LTE4 and N-ac-LTE4 were the major components excreted in the urine, mostly in the first time interval (0-12 h) of urinary collection after FMLP treatment; 11-trans-LTE4 was recovered in the second interval (12-24 h). Two other more polar compounds, potential metabolites, were recovered in the first interval of urine collection. Knowledge of the kinetic characteristics of endogenously produced leukotrienes may be useful in understanding the role of these eicosanoids in inflammatory and thrombotic disease, as well as in evaluating the efficacy of drugs designed to modulate their production and effect.

Topics: Animals; Disease Models, Animal; Humans; Infant, Newborn; Leukotriene B4; Leukotriene E4; Male; N-Formylmethionine Leucyl-Phenylalanine; Rabbits; Respiratory Distress Syndrome, Newborn

Nitric oxide is thought to play an important role in modulating the inflammatory process. Recently an increase in the inducible form of nitric oxide synthase (iNOS) has been found in the rat trinitrobenzene sulfonic acid model of experimental colitis, and inhibition of nitric oxide synthase activity resulted in an amelioration of tissue injury. The aim of our study was to evaluate in vivo intracolonic release of nitric oxide in this model of colitis. Experimental colitis was induced in male Sprague-Dawley rats by a single intracolonic administration of trinitrobenzene sulfonic acid. Nitrite levels were determined in rectal dialysates by HPLC. The tissue myeloperoxidase and iNOS and the luminal leukotriene B4 were also measured. Nitrite levels were significantly increased in rectal dialysates during colitis and correlated significantly with tissue myeloperoxidase and iNOS activity. The correlation between nitrite dialysate levels and wall iNOS activity confirms that nitrite in dialysates is produced by inflammatory cells and not by colonic bacterial flora. Determination of nitrite levels in rectal dialysates seems a valuable method to monitor colonic inflammation in rat trinitrobenzene sulfonic acid colitis.

Topics: Animals; Colitis; Colon; Disease Models, Animal; Leukotriene B4; Male; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitrites; Peroxidase; Rats; Rats, Sprague-Dawley; Trinitrobenzenesulfonic Acid

This study has examined the response of a rabbit model of inflammatory bowel disease to methylprednisolone. Colitis was induced in the colon of rabbits with 40 mg trinitrobenzenesulphonic acid in 25% ethanol (TNBS). The effect of methylprednisolone (0.5 mg/kg/day) on the development of colitis was determined at one week, by examining the colon's macroscopic and microscopic appearance, the distribution of matrix metalloproteinases (MMPs) and by measuring eicosanoid production. Although there was no difference in the area of ulcerated colonic tissue in the treated and untreated TNBS animals, the increase in polymorphonuclear leucocytes was significantly reduced in TNBS rabbits given methylprednisolone. The only difference in the distribution of MMPs was a reduction in the number of polymorphonuclear leucocytes containing gelatinase B. The release of immunoreactive PGE2 and LTB4, but not 6-keto PGF1 alpha, was increased in the TNBS animals and was unchanged by methylprednisolone. These results show that methylprednisolone does not modify the injury produced by TNBS in this model despite reducing the infiltration of polymorphonuclear leucocytes. Hence it suggests that these cells do not contribute to the injury observed, are not the source of the eicosanoids and that gelatinase B is not required in the healing process in this model.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents; Colitis; Colon; Dinoprostone; Disease Models, Animal; Eicosanoids; Leukocyte Count; Leukotriene B4; Metalloendopeptidases; Methylprednisolone; Neutrophils; Rabbits; Random Allocation; Trinitrobenzenesulfonic Acid

There are several experimental models describing in vivo eosinophil (EO) migration, including ip injection of a large volume of saline (SAL) or Sephadex beads (SEP). The aim of this study was to investigate the mechanisms involved in the EO migration in these two models. Two consecutive injections of SAL given 48 hr apart, induced a selective recruitment of EO into peritoneal cavity of rats, which peaked 48 hr after the last injection. SEP, when injected ip, promoted EO accumulation in rats. The phenomenon was dose-related and peaked 48 hr after SEP injection. To investigate the mediators involved in this process we showed that BW A4C, MK 886 and dexamethasone (DXA) inhibited the EO migration induced by SAL and SEP. To investigate the source of the EO chemotactic factor we showed that mast cells, macrophages (MO), but not lymphocytes, incubated in vitro in presence of SAL released a factor which induced EO migration. With SEP, only mast cells release a factor that induced EO migration, which was inhibited by BW A4c, MK 886 and DXA. Furthermore, the chemotactic activity of SAL-stimulated mast cells was inhibited by antisera against IL-5 and IL-8 (interleukins). SAL-stimulated MO were only inhibited by anti-IL-8 antibodies as well SEP-stimulated mast cells. These results suggest that the EO migration induced by SAL may be dependent on resident mast cells and MO and mediated by LTB4, IL-5 and IL-8. SEP-induced EO migration was dependent on mast cells and may be mediated by LTB4 and IL-8. Furthermore, IL-5 and IL-8 induced EO migration, which was also dependent on resident cells and mediated by LTB4. In conclusion, EO migration induced by SAL is dependent on mast cells and MO, whereas that induced by SEP is dependent on mast cells alone. Stimulated mast cells release LTB4, IL-5 and IL-8 while MO release LTB4 and IL-8. The IL-5 and IL-8 release by the SAL or SEP-stimulated resident cells may act in an autocrine fashion, thus potentiating LTB4 release.

Topics: Analysis of Variance; Animals; Cell Movement; Disease Models, Animal; Eosinophils; Interleukin-5; Interleukin-8; Leukotriene B4; Macrophages; Mast Cells; Peritoneal Cavity; Rats; Sodium Chloride

To assess the efficacy of leukotriene synthesis inhibitors, alone and in combination with a nonsteroidal antiinflammatory drug, as potential treatments for rheumatoid arthritis (RA), using the mouse air pouch model and the collagen-induced arthritis (CIA) model.. Two selective leukotriene synthesis inhibitors, Bay x 1005 and Bay y 1015, were compared with zileuton in terms of their ability to decrease exudate volume, cell infiltration, and leukotriene B4 (LTB4) production in response to zymosan injection in the mouse air pouch model. The mouse CIA model was used to assess the effect of leukotriene synthesis inhibitors in a model of chronic inflammation. Bay y 1015 and Bay x 1005, and the cyclooxygenase inhibitor naproxen, were evaluated individually and in combination, for their antiarthritic potency in the mouse CIA model.. The results indicate that neither zileuton, Bay x 1005, nor Bay y 1015 inhibited exudate production. All 3 compounds decreased LTB4 levels in be air pouch, with Bay y 1015 being the most effective. Cell infiltration was significantly decreased with Bay x 1005, but the degree of this decrease did not appear to correlate with LTB4 levels. No inhibition of arthritis was observed with any compound administered alone. In contrast, a significant inhibition of CIA was observed in animals that received both naproxen and either Bay y 1015 or Bay x 1005.. Inhibitors of both cyclooxygenase and leukotriene synthesis in combination may be a more effective treatment of RA than either class of inhibitors alone.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Experimental; Chronic Disease; Disease Models, Animal; Drug Combinations; Exudates and Transudates; Female; Hydroxyurea; Inflammation; Leukotriene B4; Lipoxygenase; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Naproxen; Prostaglandin-Endoperoxide Synthases; Quinolines; Time Factors; Zymosan

The acute phase protein, C-reactive protein (CRP), can increase more than a thousandfold during acute inflammatory states, and it is known to modulate neutrophil-mediated inflammatory responses. We have previously shown that CRP inhibits chemotaxis of C5a-stimulated neutrophils in vitro and that rabbits with elevated CRP blood levels exhibit diminished pulmonary vascular permeability and neutrophil infiltration in a model of alveolitis. To study the effect of CRP on alveolitis induced by different chemoattractants, transgenic mice capable of expressing rabbit CRP in a dietary-inducible fashion were treated with inflammatory doses of the chemoattractants. Intratracheal installation of FMLP (8 x 10(-10) mol), LTB4 (2 x 10(-11) mol), or IL-8 (5 x 10(-12) mol) in normal CF1 mice resulted in significant (p<0.05) influx of neutrophils and protein into the alveolar space. Transgenic mice with elevated plasma levels of CRP showed significantly (p<0.05) diminished infiltration of neutrophils into bronchoalveolar lavage fluid (BALF) and significant reduction in BALF protein compared with that in normal mice. Rabbit CRP (10 to 500 micrograms/ml) inhibited in vitro neutrophil chemotaxis in a concentration-dependent fashion when stimulated by the various chemoattractants examined. These data show that rabbit CRP can modify both in vivo and in vitro neutrophil responses to several classes of chemoattractants and that CRP has a significant protective effect in alveolitis by reducing neutrophil influx and protein leakage into the lung.

Topics: Animals; Bronchoalveolar Lavage Fluid; C-Reactive Protein; Capillary Permeability; Cell Movement; Chemotactic Factors; Chemotaxis, Leukocyte; Complement C5a; Disease Models, Animal; Dose-Response Relationship, Drug; Humans; Interleukin-8; Leukotriene B4; Lung; Mice; Mice, Inbred Strains; Mice, Transgenic; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Pneumonia; Proteins; Pulmonary Alveoli; Rabbits

Ketotifen is an anti-allergic agent that was recently shown to prevent experimental gastric and colonic mucosal injury. We studied the effect of ketotifen on indomethacin-induced small intestinal ulceration in the rat. Ulceration was produced by s.c. injection of 30 mg/kg indomethacin, 30 min after refeeding 24 h fasted rats. Total ulcer area (mm2), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were measured 24 h after indomethacin administration. Study groups received ketotifen 100 micrograms/ 100 g body weight 30 min before and 5 h after indomethacin administration, either i.p. or orally. There were 7-9 animals in each group. Ulcer area was significantly reduced by oral administration of ketotifen from 229 +/- 26 to 146 +/- 28 mm2. PGE2 level was reduced by ketotifen from 505 +/- 73 to 228 +/- 68 ng/mg protein, and LTB4 was reduced from 289 +/- 68 to 59 +/- 26 ng/mg protein. Intraperitoneal administration of ketotifen had no effect on any of the measured parameters. Ketotifen had a definite protective effect on small intestinal mucosa in the rat, which was accompanied by a reduction of mucosal inflammatory mediators. Ketotifen may have a role in the prevention or treatment of small intestinal damage induced by nonsteroidal anti-inflammatory drugs.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Dinoprostone; Disease Models, Animal; Drug Evaluation, Preclinical; Duodenal Ulcer; Histamine H1 Antagonists; Indomethacin; Ketotifen; Leukotriene B4; Male; Rats; Rats, Wistar

To assess the anti-inflammatory action of lexipafant (BB-882), a platelet activating factor antagonist, in an animal model of acute colitis.. An animal intervention study.. Following the rectal instillation of formalin 0.75% into male New Zealand White (NZW) rabbits, 0.85 ml of aggregated immunoglobulin was administered i.v. Treatment groups (0.8 mg/kg, n = 6; 2.4 mg/kg, n = 13; 3.2 mg/kg, n = 10) were given bolus doses of BB-882 two-hourly i.v. (control group, n = 25). Rectal dialysis was performed before induction of colitis and sacrifice. Dialysate leukotriene B4 (LTB4), prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) levels were determined. Tissue was saved for histology and measurement of myeloperoxidase content.. There was a dose-dependent improvement in macroscopic scores (2.4 and 3.2 mg/kg: P < 0.02, P < 0.001) and myeloperoxidase levels (3.2 mg/kg: P < 0.04). Dialysate LTB4 levels fell (2.4 and 3.2 mg/kg: P < 0.03, P < 0.02) as did PGE2 levels. TXB2 concentrations remained unaffected.. The PAF receptor antagonist BB-882 shows efficacy in treating inflammation in an animal model of acute colitis as evidenced by a dose-dependent fall in macroscopic mucosal damage, neutrophil infiltration and reduced generation of inflammatory mediators.

Topics: Animals; Colitis; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Formaldehyde; Injections, Intravenous; Intestinal Mucosa; Leucine; Leukotriene B4; Male; Platelet Membrane Glycoproteins; Rabbits; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Thromboxane B2

The mechanism of anorexia in inflammatory bowel disease is poorly understood. To gain insight into possible pathophysiologic mechanisms, the feeding indices and food intake were studied in an animal model of Crohn's disease. The anorexia of indomethacin-induced ulcerative ileitis was compared with that of the well-known anorexia of total parenteral nutrition (TPN). Forty-five female Lewis rats were randomized to four groups: Control, Indomethacin, Indomethacin + TPN, and TPN. Feeding indices and food intake were continuously measured using the Automated Computerized Rat Eater Meter. Interleukin-1 alpha (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), prostaglandin E2 (PGE2), and leukotriene B4 (LTB4) were assayed in plasma, mononuclear cell culture, or ileum to determine their role in mediating anorexia. In the TPN group, spontaneous food intake (SFI) decreased (52%; p < 0.05), primarily via reduction in meal number (MN, 54%; p < 0.05) and, to a lesser extent, meal size (MZ, 35%; p < 0.05). In comparison, in the Indomethacin group SFI decreased (74%; p < 0.05) primarily via reduction in MZ (67%, p < 0.05); MN also decreased but to a lesser extent (27%; p < 0.05). In the Indomethacin + TPN group, SFI decreased (55%; p > 0.05) primarily via reduction in MN (79%; p < 0.05), whereas MZ decreased slightly (19%; p < 0.05). Only in the Indomethacin group were IL-1 alpha and TNF-alpha detected in the mononuclear cell culture and plasma, respectively. In the Indomethacin group, an inverse correlation existed between MZ and TNF-alpha (p < 0.05). In the Indomethacin group, IL-1 alpha, PGE2, and LTB4 concentrations did not correlate with feeding indices. SFI reduction in this model was mediated primarily via a decrease in MZ. TNF-alpha is proposed to mediate this effect and TPN was shown to overcome the effect on MZ.

Topics: Animals; Anorexia; Anti-Inflammatory Agents, Non-Steroidal; Body Weight; Cells, Cultured; Dinoprostone; Disease Models, Animal; Eating; Female; Ileitis; Ileum; Indomethacin; Interleukin-1; Leukotriene B4; Monocytes; Parenteral Nutrition, Total; Rats; Rats, Inbred Lew; Tumor Necrosis Factor-alpha

The purpose of this study was to investigate the efficacy of alpha-linolenic acid-rich perilla oil emulsion (POE) in a rat model with trinitrobenzenesulfonic acid (TNB)-induced inflammatory bowel disease. Three different isocaloric solutions, which are glucose solution (FF), soybean oil emulsion (SOE) and POE, were infused for 14 days after instillation of TNB. After infusion, total cholesterol and phospholipid concentration in the plasma in the POE group were significantly decreased compared with the FF and SOE groups. Arachidonic acid level in the colonic phospholipids was significantly decreased and eicosapentaenoic acid level was significantly increased in the POE group compared with the FF and SOE groups. Thickness, damage score and leukotriene B4 content in the colon in the POE group were the lowest among the infusion groups. These results suggest that alpha-linolenic acid suppresses the synthesis of leukotriene B4 in the colon by changing the fatty acid composition in the colonic phospholipids and that POE may be effective in the improvement of inflammation in the colon.

Topics: alpha-Linolenic Acid; Animals; Body Weight; Cholesterol; Colon; Disease Models, Animal; Fatty Acids; Glucose; Inflammatory Bowel Diseases; Leukotriene B4; Male; Phospholipids; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Soybean Proteins; Trinitrobenzenesulfonic Acid

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

Bacterial products released within the gut lumen may alter the course of inflammatory bowel lesions. The effect of intraluminal N-formyl methionyl-leucyl-phenylalanine on mucosal release of inflammatory mediators was investigated in normal and colitis rats (at 1 and 7 days after induction of colitis by trinitrobenzenesulfonic acid). Under anesthesia, the distal colon was perfused using an isosmotic solution with or without synthetic N-formyl methionyl-leucyl-phenylalanine (100 nmol/ml). Effluents were assayed for eicosanoid (PGE2, TXB2 and LTB4) concentration. Myeloperoxidase activity was measured in colonic wall homogenates. In normal rats, peptide perfusion did not change mucosal release of PGE2, TXB2 and LTB4. Colitic rats showed high baseline release of eicosanoids. The peptide did not further increase PGE2 and TXB2 release, but significantly stimulated LTB4 both on days 1 and 7 after induction of colitis. Rats with high myeloperoxidase activity in the colonic wall showed a marked LTB4 response to the peptide. Finally, peptide perfusion increased tissue myeloperoxidase activity in colitis at day 7 but not in colitis at day 1 or in normal rats. In conclusion, bacterial products may activate inflammation. This mechanism of lumen-wall interaction might be involved in the perpetuation of inflammatory lesions of the colonic mucosa.

Topics: Animals; Colitis; Dinoprostone; Disease Models, Animal; Eicosanoids; Intestinal Mucosa; Leukotriene B4; Male; N-Formylmethionine Leucyl-Phenylalanine; Peroxidase; Rats; Rats, Sprague-Dawley; Thromboxane B2; Trinitrobenzenesulfonic Acid

Topics: Acetic Acid; Alkaline Phosphatase; Animals; Biomarkers; Colitis; Disease Models, Animal; Humans; Inflammatory Bowel Diseases; Leukotriene B4; Peroxidase; Quercetin; Rats; Rutin; Trinitrobenzenesulfonic Acid

Laboratory animal models and clinical studies suggest that dietary n-3 fatty acids are beneficial in diseases with an inflammatory component such as rheumatoid arthritis or psoriasis. In the present study we investigated the effect of purified docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on phorbol ester (TPA)-induced acute inflammation. Mice were fed for 6 weeks a diet containing 5% corn oil enriched with either 1% DHA or 1% EPA and compared with a group receiving 6% corn oil only. The dietary treatment with DHA or EPA elevated the n-3 polyunsaturated fatty acids as expected in the spleen and ear phospholipids, associated with a reduction in arachidonic acid levels. The degree of ear inflammation was quantified by measuring the four parameters including (1) edema as the increase in ear biopsy weight, (2) polymorphonuclear cell infiltration as myeloperoxidase activity (MPO) at the site of inflammation, (3) prostaglandin E2 (PGE2) and (4) leukotriene B4 (LTB4) concentrations in ear edema. The addition of DHA to the diet reduced significantly the edema formation and the MPO activity 24 h after TPA challenge. Both DHA and EPA significantly reduced the PGE2 and LTB4 levels compared with animals fed corn oil. This result suggests that DHA rather than EPA may be useful in the adjuvant treatment of diseases where acute inflammatory processes play a role.

Topics: Acute Disease; Animals; Anti-Inflammatory Agents; Dermatitis; Dinoprostone; Disease Models, Animal; Docosahexaenoic Acids; Ear, External; Edema; Eicosapentaenoic Acid; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Neutrophils; Peroxidase; Steroids; Tetradecanoylphorbol Acetate

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

This paper describes the use of subcutaneously-placed tissue chambers as a sterile soft-tissue inflammation model in Thoroughbred horses. Acute, non-immune inflammation was initiated by injecting a sterile lambda carrageenan solution into a tissue chamber. This model was used to study the temporal changes in oxygen and carbon dioxide tensions, pH, bicarbonate, protein, albumin, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) concentrations, cell counts and differential counts in tissue fluid from inflamed tissue chambers and control chambers. Skin temperatures over control and inflamed chambers were also compared. Carrageenan-induced inflammation resulted in significant increases in tissue-fluid carbon dioxide tension, leucocyte count, albumin, and PGE2 and LTB4 concentrations. It also resulted in a significant decrease in tissue fluid pH and HCO3-concentration. Inflammation did not result in significant changes in tissue-fluid protein concentration, differential cell counts or skin temperature over the chambers. The use of this type of tissue chamber is well-suited for studying the pathophysiology of a self-contained, non-immune inflammatory process. The model described in this paper could prove to be very useful in studies of the distribution of anti-inflammatory drugs and the effects of such drugs on various aspects of the inflammatory process.

Topics: Animals; Bicarbonates; Carbon Dioxide; Diffusion Chambers, Culture; Dinoprostone; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Exudates and Transudates; Female; Horse Diseases; Horses; Hydrogen-Ion Concentration; Inflammation; Leukocyte Count; Leukotriene B4; Oxygen Consumption; Proteins; Skin Temperature; Soft Tissue Infections; Software

Topics: Animals; Bacterial Vaccines; Bronchoalveolar Lavage Fluid; Chemotaxis, Leukocyte; Disease Models, Animal; Humans; Immunity, Mucosal; Immunization; In Vitro Techniques; Intestinal Mucosa; Leukotriene B4; Lung; Male; Neutrophils; Peyer's Patches; Pneumonia, Bacterial; Pseudomonas aeruginosa; Pseudomonas Infections; Rats

Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 fatty acyl group [predominantly arachidonic acid (AA)] of membrane phospholipids, the products of which are further metabolized, forming a variety of eicosanoids and/or platelet-activating factor. PLA2 activity is significantly enhanced during inflammation and therefore offers an intriguing target in designing anti-inflammatory drugs. SB 203347 (2-[2-[3,5-bis (trifluoromethyl) sulfonamido]-4- trifluoromethylphenoxy] benzoic acid) potently inhibits rh type II 14 kDa PLA2 (IC50 = 0.5 microM) but exhibits a 40-fold weaker inhibition of 85 kDa PLA2 (IC50 = 20 microM) using [3H]-AA E. coli as substrate. A specific interaction with rh type II 14 kDa PLA2 was confirmed both by observing the pH dependence of its IC50 and by demonstrating linear inhibition in a "scooting" kinetic model using radiolabeled phospholipid reporter substrate in a 1,2-dimyristoyl phosphatidylmethanol vesicle. Before evaluating the effect of SB 203347 on AA metabolism in intact human neutrophil, we showed that it fully inhibits PLA2 activity in acid extracted-intact human neutrophil homogenate (IC50 = 4.7 microM). SB 203347 inhibited A23187-induced intact human neutrophil AA mass release in a concentration-dependent manner (IC50 = 1 microM), which coincided with reductions in the biosynthesis of platelet-activating factor (IC50 = 1.5 microM) and leukotriene B4 (IC50 = 2.3 microM). Finally, SB 203347 prolonged survival in a mouse model of endotoxin shock delivered i.p. Taken together, the data support a role of cellular 14 kDa PLA2 in the formation of AA-derived proinflammatory lipid mediator.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 1-Alkyl-2-acetylglycerophosphocholine Esterase; Animals; Arachidonic Acid; Cell-Free System; Disease Models, Animal; Enzyme Inhibitors; Humans; Leukotriene B4; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Neutrophils; Phospholipases A; Phospholipases A2; Platelet Activating Factor; Shock, Septic; Sulfonamides; Survivors

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

The peptidoleukotrienes and leukotriene B4, formed from arachidonic acid through the action of 5-lipoxygenase (5-LO), exert a spectrum of biological effects. It has been proposed that potent and selective 5-LO inhibitors will be effective therapy in diseases in which the peptidoleukotrienes and leukotriene B4 have been implicated, such as asthma and arthritis. The novel compound (S)-N-hydroxy-N-(2,3-dihydro-6-phenylmethoxy-3-benzyofuranyl )urea (SB 202235) was evaluated as a selective inhibitor of 5-LO in a cell-free system as well as in various cellular assays. In addition, the potential therapeutic value of SB 202235 was assessed in preclinical models of allergic asthma. The activity of the 5-LO enzyme isolated from rat basophilic leukemia-1 cells was inhibited by SB 202235 in a concentration-dependent manner with an IC50 value of 1.9 microM. Consistent with its ability to inhibit 5-LO, SB 202235 inhibited the production of leukotriene B4 by human monocytes and in human whole blood (IC50 values of 1.5 microM and 1.1 microM, respectively). The selectivity of SB 202235 was confirmed by its lack of effect against several other enzymes and receptors. SB 202235 potently and effectively inhibited the contraction produced by a single concentration of ovalbumin in guinea pig trachea (IC50 = 20 microM) and of anti-IgE in human bronchus (IC50 = 2 microM). SB 202235 (3-30 microM) also inhibited the contraction of guinea pig trachea in response to increasing concentration of ovalbumin. When administered orally (30 mg/kg) to conscious guinea pigs, SB 202235 attenuated antigen-induced broncho-constriction and the subsequent eosinophil influx.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antigens; Asthma; Benzofurans; Bronchoconstriction; Disease Models, Animal; Eosinophils; Guinea Pigs; Humans; Hypersensitivity; In Vitro Techniques; Leukotriene B4; Lipoxygenase Inhibitors; Trachea; Urea

The role of leukotrienes on bone resorption was tested in a well-standardized model of bone remodeling by inhibiting their biosynthesis with BWA4C, a specific inhibitor of 5-lipoxygenase. After extraction of their upper molars unilaterally, 30 Wistar rats were divided into three groups; the first remained untreated (control group), the second received 80 mg/kg/day of BWA4C dissolved in polyethylene glycol 300 (experimental group), and the third received only the vehicle (sham-treated group). After four days of experiment, the animals were killed and the resorption profile was assessed along the antagonist mandibular buccal cortex. The main result was a dramatic decrease in the number of TRAP-positive mononucleated preosteoclasts in the experimental group (-69%, p < 0.0005 and p < 0.003 vs. the control and sham-treated groups, respectively). This drop was related to a significant decrease in the number of osteoclasts. Neither the activation of the differentiated osteoclasts nor their mean interface with the bone surface were affected by BWA4C. Concomitantly, the mast cell population residing near the vascular network limiting the periosteum was markedly and significantly increased by the treatment. These mast cells were mostly degranulating, i.e., were in a state of activation that we previously found to related to resorption. These data suggest (1) that the leukotrienes are involved in the recruitment of osteoclast progenitors, and/or their differentiation into preosteoclasts, and (2) that mast cells responded to leukotriene inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Oral; Animals; Benzeneacetamides; Bone Remodeling; Bone Resorption; Cell Differentiation; Disease Models, Animal; Hydroxamic Acids; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mandible; Mast Cells; Muscle, Smooth, Vascular; Osteoclasts; Rats; Rats, Wistar

In the present study, A23187-induced pleurisy in mice was used to investigate the anti-inflammatory effect of magnolol, a phenolic compound isolated from Chinese medicine Hou p'u (cortex of Magnolia officinalis). A23187-induced protein leakage was reduced by magnolol (10 mg kg-1, i.p.), indomethacin (10 mg kg-1, i.p.) and BW755C (30 mg kg-1, i.p.). A23187-induced polymorphonuclear (PMN) leucocyte infiltration in the pleural cavity was suppressed by magnolol and BW755C, while enhanced by indomethacin. Like BW755C, magnolol reduced both prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels in the pleural fluid of A23187-induced pleurisy, while indomethacin reduced PGE2 but increased LTB4 formation. In the rat isolated peripheral neutrophil suspension, magnolol (3.7 microM) and BW755C (10 microM) also suppressed the A23187-induced thromboxane B2 (TXB2) and LTB4 formation. These results suggest that magnolol, like BW755C, might be a dual cyclo-oxygenase and lipoxygenase inhibitor. The inhibitory effect of magnolol on the A23187-induced pleurisy is proposed to be, at least partly, dependent on the reduction of the formation of eicosanoids mediators in the inflammatory site.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Biphenyl Compounds; Body Fluids; Calcimycin; Dinoprostone; Disease Models, Animal; Leukotriene B4; Lignans; Mice; Mice, Inbred ICR; Plant Extracts; Pleura; Pleurisy; Proteins; Rats; Rats, Sprague-Dawley

Compound BW B70C, a selective 5-lipoxygenase inhibitor was tested for its ability to reduce inflammatory damage in an in vivo rabbit model of renal storage and transplantation. Kidneys were stored at 0-2 degrees C for 48 hr prior to autografting. In controls, renal vein LTB4 levels rose significantly after 30 min reperfusion but fell after 2 hr to baseline. TxB2 levels remained at baseline for the 6 hr measured. 6-k-PGF1 alpha levels rose significantly after 1 hr of reperfusion and remained elevated thereafter. Histology after 6 hr reperfusion showed moderate-to-severe cortical edema and mild congestion. Infused colloidal carbon was retained in the perivascular area in a narrow band at the corticomedullary junction, indicating a zone of vascular permeability. At 3 days after transplant, kidneys exhibited widespread tubular necrosis and calcification but little inflammation. Serum creatinine and urea peaked between days 3 and 5. 3/6 rabbits showed no symptoms of renal failure after 3 weeks. Pretreatment with BW B70C prevented the increase in LTB4 but had little effect on TxB2 and 6-k-PGF1 alpha levels. Histology showed no amelioration of cortical edema at 6 hr and congestion and hemorrhage were exacerbated. BW B70C had no effect on either colloidal carbon retention or distribution but did significantly reduce tubular necrosis and calcification at day 3. There was very little inflammatory infiltrate. BW B70C treatment did not improve the long-term viability of transplanted kidneys: 2/6 rabbits showed no symptoms of renal failure after 3 weeks. These data indicate that inhibition of LTB4 synthesis by BW B70C does not prevent the development of acute renal failure following 48 hr hypothermic storage and transplantation.

Topics: Acute Kidney Injury; Animals; Capillary Permeability; Creatinine; Disease Models, Animal; Eicosanoids; Enzyme-Linked Immunosorbent Assay; Female; Graft Rejection; Graft Survival; Hydroxylamines; Hydroxyurea; Kidney Transplantation; Kidney Tubules; Leukotriene B4; Lipoxygenase Inhibitors; Methylurea Compounds; Necrosis; Organ Preservation; Prostaglandins F; Rabbits; Thromboxane B2; Urea

In the present investigation, the effects of selective inhibitors of 5-lipoxygenase (5-LO), zileuton and TZI-41127, E-6080, AA-861 and antagonists of leukotriene B4 (LTB4) receptors, SC-41930, and SC-51146 and a selective cyclooxygenase inhibitor, indomethacin, were examined in TPA-induced acute mouse dermal inflammation. Topical application of all these agents, except indomethacin, resulted in marked attenuation of TPA-induced edema and influx of neutrophils reflected in myeloperoxidase measurements. Topically applied SC-41930 attenuated TPA-induced edema and neutrophil influx in a dose-related manner. Oral administration of LTB4 receptor antagonists either as a pre-treatment or post-treatment attenuated TPA-induced edema and influx of neutrophils. The O-demethyl analog of SC-41930, SC-37920, which was nearly 1000-fold less active than SC-41930 in LTB4 receptor binding assays, was inactive in inflammation assays, suggesting a role for LTB4 in this response. Zileuton and TZI-41127 were more effective as anti-inflammatory agents following oral administration than after i.p. administration. Intraperitoneally administered indomethacin attenuated edema response but not influx of neutrophils. Taken together, these results suggest a role for leukotrienes in acute inflammation induced by TPA and possible utility of this model to test in vivo 5-LO inhibitors and LTB4 receptor antagonists.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Benzamides; Benzopyrans; Dermatitis, Contact; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Indomethacin; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred BALB C; Receptors, Leukotriene B4; Tetradecanoylphorbol Acetate

As part of our search for novel antiinflammatory drug candidates, we have designed and synthesized a series of 3-pyridylmethyl-substituted 2-amino-6- hydroxybenzothiazoles. Introduction of a 3-pyridylmethyl group into the 2-amino group (type-A) or the benzene ring (type-B) of 2-amino-6-hydroxybenzothiazoles imparted dual inhibitory activity against the production by glycogen-induced peritoneal cells of rat (in vitro) of leukotriene B4 (LTB4) and thromboxane A2 (TXA2), while not significantly inhibiting that of prostaglandin E2 (PGE2). The observed inhibition of the former two arachidonic acid metabolites was indicated to be the result of a direct action on 5-lipoxygenase and TXA2 synthetase by a cell-free in vitro assay. On the other hand, the inhibitory activities against PGE2 production were for most compounds very weak, indicating that they did not inhibit cyclooxygenase. Structure-activity relationship studies concerning the position of the 3-pyridylmethyl group revealed that type-B compounds generally showed about 10-fold stronger inhibitory activity against TXA2 synthetase than type-A compounds. The position of the 3-pyridylmethyl group played an important role in TXA2 synthetase inhibition. When some of these compounds (8, 13a, 26a (E3040), 26b, 27b, and 28b) were orally administered in the rat TNB/ethanol-induced chronic colitis model (100 mg/kg), the production of both LTB4 and TXB2 in the rat colon was reduced (ex vivo). In addition, one type-B compound, 6-hydroxy-5,7-dimethyl-2-(methylamino)-4-(3-pyridylmethyl)benzothiazole (26a), demonstrated a therapeutic effect at treatments of 100 mg/kg po once daily for 11 days and showed almost comparable activity to sulfasalazine at a dose of 500 mg/kg, the reference drug for inflammatory bowel diseases, in this in vivo model.

Topics: Animals; Blood Platelets; Cells, Cultured; Colitis; Dinoprostone; Disease Models, Animal; Humans; Leukotriene B4; Lipoxygenase Inhibitors; Male; Peritoneal Cavity; Rats; Rats, Inbred F344; Sheep; Structure-Activity Relationship; Thiazoles; Thromboxane B2; Thromboxane-A Synthase

CI-986 is a potent inhibitor of 5-lipoxygenase and cyclooxygenase pathway product biosynthesis from rat basophilic leukemia (RBL) cells. Because metabolites from these pathways have proinflammatory properties, CI-986 was evaluated in several acute and chronic models of inflammation and hyperalgesia. The compound inhibited swelling in the carrageenan footpad edema, Mycobacterium foot-pad edema and adjuvant arthritis models of inflammation with ID40 values of 1.0, 7.7., and 7.2 mg/kg, respectively. It was roughly equivalent in potency to the standard selective cyclooxygenase inhibitor, naproxen (ID40 = 0.7, 6.3, and 3.8 mg/kg, respectively). CI-986 was also evaluated in the acetic acid induced writhing hyperalgesia assay (ID50 = 0.23 mg/kg) and was approximately equipotent with indomethacin (ID50 = 0.87 mg/kg). Although the effects of CI-986 were similar to those of standard nonsteroidal antiinflammatory drugs (NSAIDs) in the inflammation models, its gastrointestinal profile was unique. CI-986 caused no gastrointestinal irritation at doses up to 200 mg/kg in acute and chronic studies. In contrast, standard NSAIDs caused ulcers at doses of 3.7-37 mg/kg after a single dose. Moreover, CI-986 inhibited the release of LTC4 and PGE2 by gastric mucosa and reduced mucosal and vascular damage induced by oral administration of absolute ethanol to rats. These results indicate that CI-986 is a potent nonulcerogenic antiinflammatory agent with novel pharmacologic properties.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Arthritis, Experimental; Cyclooxygenase Inhibitors; Dinoprost; Disease Models, Animal; Ethanol; Female; Gastritis; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Pain; Rats; Rats, Wistar; Thiadiazoles; Tumor Cells, Cultured

Interventions that inhibit neutrophil infiltration into myocardial tissue after ischaemia and reperfusion are reported to reduce the size of the infarct. We examined whether administration of trimetazidine, which is reported to reduce myocardial infarct size, affects this process. [111In]Neutrophils and [125I]albumin were administered intravenously (i.v.) to anaesthetized rabbits to allow measurement of cell accumulation and changes in microvascular plasma protein leakage. A 30-min period of coronary artery occlusion followed by 3-h reperfusion was used, and the area at risk (AR) myocardium was defined by dye exclusion. Twelve rabbits received 2.5 mg/kg trimetazidine i.v., 10 min before coronary artery occlusion; the 13 controls received saline. In the control group, the number of [111In]neutrophils/g tissue in the AR (30,591 +/- 6,725) was significantly greater than in the normal zone (NZ, 11,519 +/- 1,605, p < 0.01). In the trimetazidine-treated group, the number of [111In]neutrophils in the AR was significantly lower than in the control group (12,717 +/- 1,958 [111In]neutrophils/g, p < 0.01). There was no significant difference in neutrophil content of the NZ (7,832 +/- 1,117 [111In]neutrophils/g) in treated animals as compared with that in control. Accumulation of [111In]neutrophils in response to intradermal administration of leukotriene B4, interleukin-8 (IL-8), or zymosan-activated plasma was not affected by the drug. The effect of trimetazidine on neutrophil accumulation into post-ischaemic reperfused myocardium therefore does not appear to result from a direct action on the neutrophil.

Topics: Animals; Blood Pressure; Capillary Permeability; Disease Models, Animal; Heart Rate; Interleukin-8; Leukotriene B4; Male; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion Injury; Neutrophils; Rabbits; Trimetazidine; Zymosan

A chemically stable prostacyclin analog, KP-10614 [(4Z,16S)-4, 5, 18, 18, 19, 19-hexadehydro-16,20-dimethyl-delta 6(9 alpha)-9(O)-methano-prostaglandin I1], was synthesized to increase the cytoprotective activity and to decrease the hypotensive activity. We have reported that KP-10614, infused i.v. at a dose of 3 ng/kg/min for 4 hr, inhibited platelet functions and reduced the experimental cardiac infarct size significantly, but did not change hemodynamic parameters and the ischemic area of the heart induced by ligation of the left descending coronary artery in rats. Accordingly, we thought that myocardial protective effects of KP-10614 might be based on the inhibition of platelet functions and cellular metabolism produced by platelets at the site of tissue injury. KP-10614 suppressed leukotriene B4 synthesis by N-formyl-methionyl-leucyl-phenylalanine-stimulated polymorphonuclear leukocytes, which was enhanced by thrombin-treated platelets in a concentration-dependent manner, even though KP-10614 did not suppress leukotriene B4 synthesis by N-formyl-methionyl-leucyl-phenylalanine-stimulated polymorphonuclear leukocytes separately in vitro. Moreover in in vivo studies, KP-10614, which was infused at a dose of 3 ng/kg/min for 4 hr, suppressed leukotriene B4 content, myeroperoxidase activity and polymorphonuclear leukocyte counts in myocardial tissues that were infarcted by ligation of the left descending coronary artery for 4 hr in rats. These data supported the hypothesis that KP-10614, a new prostacyclin analog, had protective effects on myocardial infarction in rats by suppressing the platelet-polymorphonuclear leukocyte interaction at the site of tissue injury in vivo.

Topics: Animals; Blood Platelets; Cell Communication; Cells, Cultured; Disease Models, Animal; Epoprostenol; Fibrinolytic Agents; Iloprost; Leukotriene B4; Male; Myocardial Infarction; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Peroxidase; Rabbits; Rats; Rats, Sprague-Dawley

To evaluate the hypothesis that treatment with LY255283, a novel leukotriene B4-receptor antagonist, is beneficial in an animal model of the adult respiratory distress syndrome induced by endotoxin.. Prospective, randomized, controlled trial.. Laboratory at a large university medical center.. Twenty-five, immature, random-bred swine.. Four groups of pigs were studied: the LPS group of animals (n = 6) were infused with Escherichia coli lipopolysaccharide (strain 0111:B4, 250 micrograms/kg) from 0 to 60 mins; the LPS + 255283 group of animals (n = 6) were infused with lipopolysaccharide as above, but were also treated with LY255283 (30 mg/kg, then 10 mg/kg/hr), beginning at -15 mins; the 255283 group of animals (n = 6) were infused with the same dose of LY255283, but were not challenged with lipopolysaccharide; and the RL control group of subjects (n = 7) received only the lactated Ringer's solution vehicle. Beginning at 30 mins, all groups were infused with dextran-70 solution as needed to maintain cardiac output at 90% to 110% of baseline value.. Treatment with LY255283 significantly (p < .05) ameliorated lipopolysaccharide-induced systemic arterial hypotension, pulmonary arterial hypertension, and arterial hypoxemia. Treatment with this drug also abrogated lipopolysaccharide-induced increases in pulmonary extravascular water content and bronchoalveolar lavage fluid protein concentration.. These data suggest that leukotriene B4 may be an important mediator of acute lung injury in this porcine model of septic shock and acute lung injury. Further studies to assess the specificity of LY255283 as a leukotriene B4 antagonist are necessary in order to exclude the possibility that the beneficial effects of this compound are due to pharmacologic actions other than the blockade of LTB4 receptors.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Drug Evaluation, Preclinical; Escherichia coli Infections; Extravascular Lung Water; Hemodynamics; Leukotriene B4; Male; Peroxidase; Proteins; Random Allocation; Respiratory Distress Syndrome; Shock, Septic; Swine; Tetrazoles; Thromboxane B2

SC-41930, 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxy]-3,4- dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid, is a selective, orally active, LTB4 receptor antagonist currently in clinical trials for psoriasis and ulcerative colitis. Exhaustive SAR studies found a potential backup compound, SC-50605, which was 7-16 times more potent than SC-41930 in LTB4 receptor binding, chemotaxis and degranulation assays. SC-50605 also inhibited LTB4-induced intradermal chemotaxis in cavine skin at an oral dose of 0.10 mg/kg and displayed good activity in animal models of colitis and epidermal inflammation both orally and topically.

Topics: Animals; Benzopyrans; Binding Sites; Cell Degranulation; Chemotaxis, Leukocyte; Colitis; Dermatitis; Disease Models, Animal; Drug Design; Guinea Pigs; In Vitro Techniques; Leukotriene B4; Mice; Receptors, Leukotriene B4; Thiazoles

ETH615 (4-[2-quinolylmethoxy]-N-[3-fluorobenzyl]-phenylaminometh yl-4-benzoic acid) is a potent inhibitor of leukotriene biosynthesis in A23187-stimulated leukocytes, and of IL-8 gene expression in LPS-stimulated PBMC. It shows anti-inflammatory activity in a canine model of dermal inflammation. A topical formulation is present in phase II clinical trials. In the present study the effect of ETH615 on oxazolone-induced acute inflammation and phorbol ester-induced chronic inflammation in the mouse ear was investigated. Betamethasone (0.04 mg/ear) and ETH615 (1-1.5 mg/ear) significantly inhibited both the oedema formation and the PMN infiltration. The cream and ointment formulations of ETH615 developed for clinical studies were equally active. ETH615 is thus an anti-inflammatory agent in these murine models of dermatosis.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Betamethasone; Dermatitis; Disease Models, Animal; Ear; Edema; Gene Expression; Interleukin-8; Leukotriene B4; Mice; Oxazolone; Peroxidase; Quinolines; T-Lymphocytes; Tetradecanoylphorbol Acetate

To evaluate anti-colitic efficacy, eight cotton-top tamarins (CTTs) with histologically confirmed persistent active colitis were given the anti-inflammatory agent SC-41930 (10 mg/kg BW by gavage BID) for eight weeks. Colonic endoscopy and biopsy observations, CBCs and clinical chemistries, and stool consistency were evaluated pre-, mid-, and posttreatment. Colitic activity was graded histologically from A1 (mild) to A5 (severe); results varied among the seven animals that completed the study: five improved, one worsened, and one was unchanged. Serum enzyme levels were significantly reduced with treatment. Stool condition remained puddly throughout treatment and body weights did not vary from pretreatment levels. However, SC-41930 produced histological evidence (reduced numbers of polymorphonuclear cells) of anti-colitic efficacy over an eight-week treatment period in CTTs with persistent active colitis. These results support the use of the CTT colitis model to evaluate efficacy of therapeutic agents and provide useful predictive information to aid in the medical management of human IBD.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzopyrans; Body Weight; Colitis; Colon; Disease Models, Animal; Leukotriene B4; Saguinus

Use of the CTT model provides insight into the inflammatory mediator contribution in the pathogenesis of idiopathic colitis. To evaluate anti-colitic efficacy, the leukotriene B4 receptor antagonist and anti-inflammatory agent, SC-41930, was administered (10 mg/kg BW by gavage BID) for 8 weeks to CTTs with histologically confirmed persistent and defined active colitis. The inflammatory mediators LTB4, PGE2, TXB2, and PAF were assayed in colonic dialysate that was collected after 1 1/2 h from four CTTs pre-, mid-, and post-treatment, frozen at -70 degrees C, and analyzed by RIA after HPLC purification. LTB4 levels were lower at mid- and post-treatment and had little inter-animal variation post-treatment. PGE2 and PAF levels were elevated during SC-41930 treatment, but there was a trend towards lower thromboxane B2 levels. Reduced LTB4 (PMN degranulation and chemotaxis) and increased PGE2 (mucosal-protective effect) may, in part, explain the observed efficacy of SC-41930 in active tamarin colitis.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acids; Benzopyrans; Colitis; Colon; Dinoprostone; Disease Models, Animal; Leukotriene B4; Platelet Activating Factor; Radioimmunoassay; Saguinus; Thromboxane B2

The effects and mechanism of action of PF-10040, a quinoline derivative, were examined in an experimental model of NSAID-gastritis. Oral pretreatment with PF-10040 dose-dependently reduced the severity of indomethacin-induced gastric damage, with a significant protective effect being observed with doses of 10 mg/kg or greater. The protective effects of this compound persisted for as long as 6 h after administration. PF-10040 also significantly reduced the severity of aspirin- or naproxen-induced gastric damage. At protective doses, PF-10040 did not significantly affect gastric LTB4 synthesis, LTB4-induced granulocyte recruitment to intradermal injection sites, or LTD4-induced changes in gastric blood flow. The free radical scavenging effects of PF-10040 were examined using an in vitro assay, in which it failed to exert significant effects at concentrations of up to 10 mM. PF-10040 had no significant effect on gastric acid secretion. In rat mesenteric venules, PF-10040 inhibited PAF-, but not LTB4-induced leukocyte adherence and emigration. These results suggest that the protective effects of PF-10040 are not attributable to scavenging of free radicals, inhibition of leukotriene synthesis, blockade of LTB4 or LTD4 receptors or inhibition of LTB4-mediated leukocyte endothelial cell adhesion.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Adhesion; Cell Movement; Disease Models, Animal; Free Radical Scavengers; Gastric Acid; Gastric Mucosa; Gastritis; Isoquinolines; Leukocytes; Leukotriene B4; Male; Platelet Activating Factor; Rats; Rats, Sprague-Dawley; Rats, Wistar; Stomach; Vasoconstriction

One of the mechanisms by which corticosteroids may modify acute graft vs host disease (GvHD) is via inhibition of arachidonic acid (AA) metabolism. Leukotriene B4 (LTB4) is a product of that pathway which may take part in the pathogenesis of GvHD through the stimulation of T-lymphopoiesis and T-lymphocyte activation. LTB4 is a metabolite of AA (20:4n-6). Alternate dietary sources of polyunsaturated fatty acids (PUFA), specifically eicosapenteinoic acid (20:5n-3) (EPA) and docosahexaenoic acid (22:6n-3) (DHA), shift the LTs formed with a decrease in LTB4 an increase in LTB5. LTB5 is a less potent agonist than LTB4 and this results in a theoretical decrease of LTB4 mediated events. Supplementation of in vitro bone marrow cultures with EPA or DHA had no detrimental effect on myeloid colony formation. Dietary EPA/DHA supplementation in mice with induced GvHD appeared to be safe and well tolerated. The LTB4:LTB5 ratio shifted from 7.65 +/- 1.75 in control-fed animals to 1.03 +/- 0.18. Fish-oil-supplementation did not compromise engraftment or stem cell content. Alone, this therapy was unable to modify GvHD.

Topics: Animals; Arachidonic Acid; Bone Marrow; Disease Models, Animal; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fish Oils; Graft vs Host Disease; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; In Vitro Techniques; Leukotriene B4; Lipoxygenase; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Spleen; T-Lymphocytes

Biofor 389 (BF389), dihydro-4-[[3,5-bis(1,1-dimethyl)-4-hydroxyphenyl] methylene]-2-methyl-2H-1,2-oxazin-3(4H)-one, was tested for anti-inflammatory activity in various animal models of arthritis. Initial evaluation in the lipoidalamine (LA) arthritis model in rats (5-day dosing protocol) resulted in an oral ED50 of 4.9 mg/kg for inhibition of paw swelling. No effects on splenomegaly were observed, suggesting that the compound was efficacious as a result of anti-inflammatory rather than immunomodulatory effects. BF389 was efficacious in interleukin 1 (IL-1)-enhanced type II collagen arthritis in rats (oral ED50 less than 1.0 mg/kg) as assessed by paw volume measurement and histologic evaluation of joints. Mice with IL-1-enhanced type II collagen arthritis given 30 mg/kg of BF 389 had significantly lower histological scores for joint damage than did untreated controls. Normal rats given single oral doses of BF389 had significant suppression of arachidonate-stimulated whole blood prostaglandin E2 and thromboxane B2 production 2 hr postdosing (ED50 = 0.1 mg/kg). Leukotriene B4 production in these animals was not decreased. After it became apparent that the compound was a potent inhibitor of prostaglandin production in vivo, a study was done to compare the efficacy and toxicity of BF389 with several currently marketed nonsteroidal anti-inflammatory drugs, piroxicam, naproxen and diclofenac. Lipoidalamine-injected rats were given daily oral doses of BF389 or the comparators for 21 days. Quantitation of effects on arthritis on day 21 resulted in ED50 values of 0.9 mg/kg (BF389), 3.9 mg/kg (naproxen), 4.9 mg/kg (diclofenac) and 0.6 mg/kg (piroxicam).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Arthritis, Experimental; Collagen; Diamines; Diclofenac; Dinoprostone; Disease Models, Animal; Female; Interleukin-1; Leukotriene B4; Male; Naproxen; Oxazines; Phenols; Piroxicam; Rats; Rats, Inbred Lew; Thromboxane B2

Nephrotoxic nephritis, a model system for glomerulonephritis, is characterized by glomerular inflammation, proteinuria, and a marked increase in ex vivo glomerular eicosanoid production. This study addressed whether urinary eicosanoids might serve as noninvasive markers for glomerular inflammation and damage with nephrotoxic nephritis and its accelerated variant. Accelerated nephritis, relative to simple nephritis, was characterized by more substantial glomerular inflammation, particularly that due to neutrophils. Correspondingly, accelerated nephritis was accompanied by greater proteinuria and more marked elevations in glomerular eicosanoids generated ex vivo. With respect to urinary eicosanoids, thromboxane, but not leukotriene B4, was detected in the urine of normal animals. After the induction of nephrotoxic nephritis, urinary thromboxane was moderately elevated (twofold) and urinary leukotriene B4 was variably present (three of seven animals). In accelerated nephritis, urinary thromboxane was more markedly elevated (sixfold) and leukotriene B4 was consistently present. The presence of urinary leukotriene B4 was confirmed by gas chromatography/mass spectrometry. Urinary eicosanoids together correlated with glomerular leukocyte numbers and proteinuria by linear regression. Urinary leukotriene B4 individually correlated with glomerular neutrophil numbers. Renal metabolism of leukotriene B4 to omega oxidation products by the rat kidney was not apparent. These data validate that the enhanced glomerular eicosanoid metabolism seen in nephrotoxic nephritis takes place in vivo and additionally suggest that both urinary thromboxane and leukotriene B4 may serve as noninvasive markers for glomerular inflammation and damage. In light of these and prior studies, urinary thromboxane may be a general marker of glomerular inflammation and leukotriene B4 may be a more specific index of acute inflammation.

Topics: Animals; Biomarkers; Disease Models, Animal; Eicosanoids; Glomerulonephritis; In Vitro Techniques; Kidney Glomerulus; Leukotriene B4; Perfusion; Rats; Rats, Inbred Lew; Thromboxanes

The effects of cyclooxygenase inhibitors flurbiprofen and indomethacin on the inflammatory response and immune reactions induced by S-antigen in the rat eye were studied. The treatment with flurbiprofen and indomethacin administered subcutaneously every 12 hours, commenced on the day of S-antigen injection and was continued until the termination of the experiment (12 days). Flurbiprofen reduced vasodilation and the inflammatory exudate into the anterior chamber by 38% and 36% respectively while inhibiting polymorphonuclear leukocytes infiltration by 57% without affecting monocytes infiltration. Indomethacin had similar but greater effects than flurbiprofen on all these parameters. However, the differences between the mean values of the two compounds were not significant. Both compounds also attenuated spleen cell proliferation, serum IgG levels to S-antigen and interferon-gamma levels in the aqueous humor. The level of prostaglandin E2, but not of leukotriene B4, was increased in the untreated inflamed uveal tissues and this increase was significantly inhibited by flurbiprofen and indomethacin. The results of this study suggest that cyclooxygenase products are involved in the normal development of both humoral and cellular immune response in the experimental uveitis.

Topics: Animals; Antigens; Arrestin; Autoantibodies; Dinoprostone; Disease Models, Animal; Eye Proteins; Female; Flurbiprofen; Immunoglobulin G; Indomethacin; Injections, Subcutaneous; Leukotriene B4; Membrane Proteins; Neutrophils; Phosphodiesterase Inhibitors; Rats; Rats, Inbred Lew; Uveitis

Eicosanoids, derivatives of arachidonic acid, play a role in several inflammatory diseases of the bowel. To determine whether prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and leukotriene C4D4E4 (LTC4D4E4), have a role in hypoxic insult to the intestine, we examined the levels of these mediators in a hypoxic neonatal rabbit model. One group of animals underwent hypoxic insult postnatally, the second group did not undergo hypoxia and served as a control. The levels of PGE2, LTB4, and LTC4D4E4 were determined by radioimmunoassay. PGE2 in the hypoxic group was 1,779 +/- 142 pg/mg protein (mean +/- SD) as opposed to 2,380 +/- 197 pg/mg protein in the control group (p less than 0.02). LTB4 level was 5,446 +/- 3,492 pg/mg protein in the hypoxic rabbits and 3,362 +/- 2,570 pg/mg protein in the control group (p less than 0.03). There was no statistically significant difference in the level of LTC4D4E4 between the two groups. Our study shows that hypoxia shifts the arachidonic acid metabolism toward enhanced lipoxygenase activity with a resultant increase in LTB4 levels and a concomitant decrease in cyclooxygenase activity with reduced PGE2 levels in the bowel. The shift in the balance between these eicosanoids may play a role in the pathogenesis of ischemic-hypoxic bowel diseases by enhancing the inflammatory response in the intestine, and simultaneously, diminishing cytoprotection.

Topics: Animals; Animals, Newborn; Dinoprostone; Disease Models, Animal; Eicosanoids; Hypoxia; Intestinal Mucosa; Leukotriene B4; Rabbits; SRS-A

Tumor necrosis factor-alpha (TNF) is a cytokine released by mononuclear cells in response to inflammation and sepsis. Since the biological effects of TNF are consistent with the systemic and intestinal features of ulcerative colitis, the role of TNF was examined in a rabbit model of chronic colitis. Peripheral blood mononuclear cells were isolated, stimulated with lipopolysaccharide, and cultured supernatants assayed for TNF levels using a cytotoxic assay on mouse fibrosarcoma L929 cells. Basal levels of TNF production by mononuclear cells from 13 normal rabbits (124.3 units/ml +/- 27.1 units/ml, mean +/- SE) were not different from nine rabbits with colitis (83.6 units/ml +/- 24.4 units/ml, P > 0.05). Treatment with lipopolysaccharide (100 micrograms/ml) induced increased TNF production by mononuclear cells isolated from both normals (672.0 units/ml +/- 197.5 units/ml, P < 0.05) and rabbits with colitis (1114.0 units/ml +/- 489.6 units/ml, P < 0.05). However, at all lipopolysaccharide concentrations stimulated TNF levels were comparable in experimental and control groups (P > 0.05). In light of the role of leukotrienes in inflammation, a separate group of rabbits with colitis was investigated following treatment with an oral leukotriene B4 receptor antagonist. Serum TNF levels in 15 control rabbits (32.5 units/ml +/- 7.6 units/ml, mean +/- SE) were not significantly different from rabbits with colitis receiving either leukotriene B4 receptor antagonist (35.7 units/ml +/- 9.2 units/ml, N = 13) or vehicle alone (50.3 units/ml +/- 10.2 units/ml, N = 14) (ANOVA, P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Benzopyrans; Cells, Cultured; Colitis, Ulcerative; Dinitrochlorobenzene; Disease Models, Animal; Escherichia coli; Leukocytes, Mononuclear; Leukotriene B4; Lipopolysaccharides; Rabbits; Receptors, Immunologic; Receptors, Leukotriene B4; Tumor Necrosis Factor-alpha

1. This paper describes the pre-clinical pharmacology of ICI D2138, a potent orally-active non-redox inhibitor of 5-lipoxygenase which is undergoing clinical evaluation. 2. ICI D2138 potently inhibited leukotriene synthesis in murine peritoneal macrophages (IC50 = 3 nM) and human blood (IC50 = 20 nM). In human and dog blood, ICI D2138 did not inhibit thromboxane B2 synthesis at a concentration of 500 microM, thus the selectivity ratio (cyclo-oxygenase: 5-lipoxygenase) was greater than 20,000. In contrast, zileuton (a 5-lipoxygenase inhibitor also undergoing clinical evaluation) exhibited a selectivity ratio of 15-100. 3. ICI D2138 potently and dose-dependently inhibited ex vivo leukotriene B4 (LTB4) synthesis by rat blood with ED50 values of 0.9, 4.0 and 80.0 mg kg-1 p.o. at 3, 10 and 20 h respectively after dosing. Similar activity was observed for inhibition of LTB4 production in a zymosan-inflamed rat air pouch model. Zileuton produced ED50 values of 5 and 20 mg kg-1 at 3 and 10 h respectively. 4. Oral administration of 1, 3 or 10 mg kg-1 ICI D2138 to dogs produced maximal inhibition of ex vivo LTB4 synthesis by blood for 5, 9 and 31 h respectively. A dose of 5 mg kg-1 p.o. of zileuton caused maximal inhibition of LTB4 for 24 h. 5. Oral administration of 10 mg kg-1 ICI D2138 caused total inhibition of LTB4 production in zymosan-inflamed rabbit knee joint. 6. Topical administration of ICI D2138 to rabbit skin caused a dose-related inhibition of arachidonic acid-induced plasma extravasation with an ID30 of 1.08 nmol per site. Zileuton was approximately 40 times less potent.7. Oral anti-inflammatory activity was assessed in an arachidonic acid-induced mouse ear oedema model in animals treated with indomethacin to block pro-inflammatory prostanoids. ICI D2138, given orally, caused dose-dependent inhibition of oedema with an approximate ID50 of 1.8 mg kg'. Zileuton was approximately 10 times less potent.8. ICI D2138 caused a dose-dependent inhibition of antigen-induced broncho-constriction in guineapigs with an approximate ID50 of 0.1 mg kg-', i.v. Zileuton was approximately 10 times less potent.9. In view of the pharmacological profile described here, ICI D2138 has the potential to provide improved clinical efficacy compared to existing lipoxygenase inhibitors such as zileuton.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Bronchoconstriction; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Guinea Pigs; Hydroxyurea; Inflammation; Knee Joint; Leukotriene B4; Lipoxygenase Inhibitors; Macrophages; Male; Mice; Oxidation-Reduction; Pyrans; Quinolones; Rabbits; Rats; Thromboxane B2

Anti-inflammatory actions of dexamethasone (DEXA), Cyclosporin A (CSA) and Rapamycin (RAPA) were assessed on uveitis induced by intravitreal E-coli Endotoxin (100ng) in rabbits at 24 hrs. In this model, endotoxin caused a breakdown of the blood-aqueous barrier (BAB) and polymorphonuclear neutrophils (PMN) infiltration into the aqueous humor (AH) and iris-ciliary body (ICB). Intramuscular (I.M.) DEXA (2mg/kg) but not topical DEXA (0.1% 6 x daily) inhibited AH leukocytes and protein level. However, both routes caused an inhibition of AH Prostaglandin E2 (PGE2) and Leukotriene B4 (LTB4). In the ICB, I.M. DEXA significantly inhibited PGE2 synthesis and myeloperoxidase (MPO) activity. I.M. CSA (25mg/kg) and I.M. RAPA (10mg/kg) inhibited the AH leukocytes and protein content and MPO activity in the ICB. RAPA also inhibited AH protein and eicosanoid (except AH LTB4) levels in both the AH and ICB. Interestingly, castor oil, a vehicle of CSA, also inhibited AH leukocytes and the release of PGE2 into AH and from ICB. In summary, systemic administration of DEXA and other immunosuppressive drugs CSA and RAPA significantly inhibited endotoxin-induced uveitis in rabbits.

Topics: Animals; Aqueous Humor; Ciliary Body; Cyclosporine; Dexamethasone; Dinoprostone; Disease Models, Animal; Endotoxins; Immunosuppressive Agents; Iris; Leukocyte Count; Leukotriene B4; Neutrophils; Peroxidase; Polyenes; Rabbits; Sirolimus; Uveitis, Anterior

Topics: Administration, Oral; Administration, Topical; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Cell Degranulation; Chromatography, Gel; Disease Models, Animal; Edema; Glucuronidase; Leukotriene B4; Mice; Mice, Inbred BALB C; Neutrophils; Novobiocin; Rabbits; Skin Diseases; Streptomyces

TNF is a potent cytokine which can induce many of the pathological changes associated with inflammatory disease. In vitro studies have demonstrated that 5-lipoxygenase products promote the production of TNF by activated macrophages, suggesting that 5-lipoxygenase inhibitors may have therapeutic utility for the treatment of inflammatory conditions. A rat airpouch model of inflammation has been used to investigate the relationship between eicosanoid generation and TNF production in vivo. Injection of zymosan into the airpouch caused a time-dependent stimulation of TNF production which preceded leukotriene generation by at least 30 minutes. Injection of LPS into the airpouch also stimulated TNF production but not leukotriene generation. The selective 5-lipoxygenase inhibitors, ICI207968, A64077 and BWA4C, and the 5-lipoxygenase translocation inhibitor MK886, decreased leukotriene generation but enhanced TNF production. Taken together, these results do not support a role for 5-lipoxygenase products in the regulation of TNF production in vivo.

Topics: Animals; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Indomethacin; Inflammation; Kinetics; Leukotriene B4; Lipopolysaccharides; Lipoxygenase Inhibitors; Male; Rats; Rats, Inbred Strains; SRS-A; Tumor Necrosis Factor-alpha; Zymosan

Intraperitoneal and intra-articular (knee joint) injection of zymosan in the rat caused two phases of increased vascular permeability, a rapid increase (0.25-0.5 h) and a secondary increase (2-3 h) which was temporally associated with the onset of leukocyte infiltration. Intraperitoneal injection of zymosan led to a single peak of eicosanoid production (LTB4, C4, D4, E4 and 6-oxo-PGF1 alpha) which was maximal at 0.125-0.25 h. Intra-articular injection led to an initial peak of LTB4 production (maximal at 0.25 h) and a secondary peak of LTB4 and PGE2 production (maximal at 3 h). Oral administration of the 5-lipoxygenase (5-LO) inhibitors phenidone, BW A4C (N-hydroxy-N-[3-(3-phenoxyphenyl)-2-propenyl] acetamide), A63162 (N-hydroxy-N-[1-(4-(phenylmethoxy) phenyl)ethyl] acetamide and ICI 207 968 (2-[3-pyridylmethyl]-indazolinone inhibited LTB4 production in A23187 stimulation blood ex vivo. The glucocorticosteroid dexamethasone had no effect in this model. The initial phase of increased vascular permeability in the peritoneal cavity and LTB4 production was dose dependently inhibited by the 5-LO inhibitors phenidone, BW A4C, A63162, and ICI 207 968 but not by dexamethasone or colchicine. The initial phase of increased permeability in the joint was unaffected by phenidone, BW A4C, dexamethasone or colchicine. However the latter two drugs inhibited the later phase of increased permeability and leukocyte infiltration in the joint and peritoneal cavity. These results demonstrate that zymosan induces eicosanoid production in vivo but the relative importance of these mediators varies depending on the inflammatory site.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arthritis; Benzeneacetamides; Calcimycin; Colchicine; Dexamethasone; Dinoprostone; Disease Models, Animal; Hydroxamic Acids; Inflammation; Kinetics; Knee Joint; Leukocytes; Leukotriene B4; Leukotrienes; Lipoxygenase Inhibitors; Male; Peritonitis; Pyrazoles; Rats; Zymosan

The role of metabolites of arachidonic acid (AA) in experimental autoimmune uveoretinitis was studied using inhibitors of AA metabolism. Nordihydroguaiaretic acid (NDGA), which inhibits predominantly the lipoxygenase (LO) pathway, or indomethacin, a specific cyclo-oxygenase (CO) inhibitor, was administered to rats immunized with retinal S antigen. Levels of various AA metabolites were measured in the inflamed uvea, and the severity of intraocular inflammation was quantitated by morphometric analysis. Histopathologically, the uveoretinitis was significantly suppressed following treatment with NDGA, while indomethacin treatment resulted in augmentation of the disease (p less than 0.05). These results tend to indicate that the inhibition of the LO rather than the CO pathway may be more beneficial in the treatment of autoimmune uveitis.

Topics: Animals; Anthropometry; Anti-Inflammatory Agents, Non-Steroidal; Antigens; Arrestin; Dinoprostone; Disease Models, Animal; Eye Proteins; Female; Indomethacin; Leukotriene B4; Masoprocol; Radioimmunoassay; Rats; Rats, Inbred Lew; Retinitis; Thromboxane B2; Uveitis, Posterior

The anti-inflammatory effects of vitamin E were investigated using the S antigen model of uveoretinitis. Thirty-six 3-week-old Lewis rats were separated into three groups and maintained on a specially formulated diet. One group of animals received a diet deficient in vitamin E; a second group received a normal diet containing vitamin E, and the third group, in addition to receiving the normal diet, received vitamin E supplementation. At 9 weeks of age, all rats were sensitized to S antigen. Six animals in each group were killed on day 14 and the remaining animals on day 21 following immunization. Both histopathologic and biochemical studies were conducted to evaluate the tissue damage observed in animals maintained on different dietary levels of the vitamin. The intraocular inflammation in the vitamin E-supplemented group was considerably smaller than in the other two groups (p less than 0.01). The former group had the highest level of vitamin E in both the eye and plasma (mean value 1.13 micrograms/mg protein and 23.9 micrograms/ml, respectively), while the vitamin E-deficient group had the lowest levels (mean values of 0.16 micrograms/mg protein and 0.48 micrograms/ml in the eye and plasma, respectively). Results of the radioimmunoassay for the determination of the arachidonic acid metabolites revealed significantly lower levels of thromboxane B2 in the vitamin E-supplemented group (2.04 +/- 0.45 pg/mg) than in the normal (4.33 +/- 0.98 pg/mg) or the vitamin E-deficient (5.21 +/- 1.12 pg/mg) groups (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antigens; Arrestin; Autoantigens; Choroid; Diet; Dinoprostone; Disease Models, Animal; Eye Proteins; Female; Leukotriene B4; Membrane Proteins; Phosphodiesterase Inhibitors; Radioimmunoassay; Rats; Rats, Inbred Lew; Retinitis; Thromboxane B2; Uveitis; Vitamin E

The role of endogenously released eicosanoids in intraocular inflammation was assessed in two rabbit models. The models were: (1) paracentesis in which only breakdown of blood-aqueous barrier (BAB) occurs and (2) uveitis induced by endotoxin in which the disruption of the BAB and polymorphonuclear leukocyte infiltration are the predominant events. Indomethacin (a specific cyclooxygenase inhibitor) applied topically inhibited both the disruption of the BAB and increased levels of aqueous humor 6-keto-Prostaglandin (PG)F1 alpha. However, indomethacin and flurbiprofen applied topically and BWA4C or BWA218C (both selective lipoxygenase inhibitors) given parenterally, did not inhibit BAB response in endotoxin-induced uveitis. The cyclooxygenase inhibitors attenuated PGE2 release into aqueous humor. The 5-lipoxygenase inhibitors reduced the PMN infiltration as well as LTB4 release into aqueous humor. However, myeloperoxidase activity (an index for PMN chemotaxis) in iris-ciliary body was not affected by these drugs. Furthermore, concentrations of LTB4 in aqueous humor after paracentesis and uveitis-induced by endotoxin were similar, although in the former model there was no leukocyte infiltration, but in the latter model this leukocyte response was predominant. The results of this study suggest that locally released autocoids may not initiate ocular inflammation and other mediators such as cytokines may be involved in the inflammatory responses of the rabbit eye. We tried to detect IL-1 activity in aqueous humor following endotoxin. However, we could not detect the presence of IL-1-like activity, possibly because endotoxin also releases PGs, which inhibit IL-1 bioassay.

Topics: Animals; Aqueous Humor; Biological Transport, Active; Blood; Ciliary Body; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Endotoxins; Escherichia coli; Interleukin-1; Iris; Leukocyte Count; Leukotriene B4; Lipoxygenase Inhibitors; Male; Peroxidase; Rabbits; Uveitis

Spontaneous colitis in CTT's presents cytological characteristics similar to chronic ulcerative colitis in humans, e.g. inflammatory cell infiltrate and crypt abscesses. To better characterize CTT colitis as a potential model for human inflammatory bowel disease (IBD), inflammatory mediators identified in colonic tissue of human IBD patients and/or experimental colitis models were assayed. Inflammatory mediator changes in plasma and colon from tamarins with acute (n = 10) and chronic (n = 10) colitis (by mucosal biopsy) were assayed by RIAs. Similar inflammatory mediators were found in the CTT's with acute colitis. In the plasma, PAF and PGE2 levels were lower in acute colitis CTT's, no LTB4 was detected, and histamine levels were not different from chronic colitic animals. In the colon, myeloperoxidase and interleukin-1 beta were significantly higher in acute colitis, PGE2 and LTB4 were higher but not significantly, and PAF was not different from chronic CTT's. These data suggest that a combination of events are occurring in the pathogenesis of tamarin colitis that involves some of the same mediators that are found in the human disease and in other experimental models. The importance of these findings to human IBD remains for further investigation; however, the spontaneous primate model offers an exciting approximation of the disease development and merits further investigation for understanding the pathogenesis of human IBD as well as to aid in development of targeted therapeutics.

Topics: Acute Disease; Animals; Chronic Disease; Colitis; Dinoprostone; Disease Models, Animal; Histamine; Interleukin-1; Leukotriene B4; Peroxidase; Platelet Activating Factor; Saguinus

Arachidonic acid solution (2 to 15 mg/ml) was infused into the right forebrain white matter of anaesthetised cats over three hours to evaluate its contribution to the genesis and pathophysiology of vasogenic brain oedema. The 0.6 ml infusion increased local white matter water content by a mean of 11.3 ml/100 g tissue but did not increase cortical water content. Histological studies revealed local expansion and trabeculation of the white matter with aggregations of granulocytic neutrophils in the venules and perivenular brain. The adjacent cortical cytoarchitecture was normal. The white matter around the infusion site was stained lightly and over a variable area (15-20 mm2) by intravenously administered Evans Blue dye 2%. Regional cerebral blood flow (rCBF) adjacent to the frontal infusion did not change significantly during the period of infusion and remained similar to rCBF in the contralateral hemisphere. Following the arachidonic acid infusion regional CBF CO2 reactivity was normal and three was no asymmetry of either cortical somatosensory evoked potential (SEP) or motor evoked potential (MEP) waveforms. The increase in brain water content and changes in the ICP and ICP related biodynamics (pressure-volume index, lumped craniospinal compliance and CSF outflow resistance) were similar to those seen following infusion of 0.6 ml saline. These studies suggest that free intraparenchymal arachidonic acid, at concentrations exceeding those occurring in most neuropathological conditions, can increase the normal brain parenchymal capillary permeability but does not disrupt focal cerebrovascular and electrophysiological function. The clinical implications of these findings are discussed.

Topics: Animals; Arachidonic Acid; Blood-Brain Barrier; Brain Edema; Cats; Cerebral Cortex; Cerebrospinal Fluid Pressure; Disease Models, Animal; Evoked Potentials, Somatosensory; Intracranial Pressure; Leukotriene B4; Muscles; Reaction Time; Regional Blood Flow; Specific Gravity; SRS-A; Synaptic Transmission; Vascular Resistance

The role of metabolites of arachidonic acid in experimental Pseudomonas keratitis was studied using inhibitors of arachidonic acid metabolism. Nordihydroguaiaretic acid 1%, which inhibits predominantly the lipoxygenase pathway, and flurbiprofen 0.03%, which inhibits predominantly the cyclo-oxygenase pathway were administered topically to rabbit eyes after intrastromal injection of Pseudomonas aeruginosa. Levels of the cyclo-oxygenase product prostaglandin E2 (PGE2) and the lipoxygenase product leukotriene B4 (LTB4) were measured, and the number of ulcers that had progressed to descemetocele formation by 24 hours was determined. Corneal ulceration was accelerated by flurbiprofen, but nordihydroguaiaretic acid limited the flurbiprofen-induced worsening. The use of flurbiprofen was associated with decreased levels of PGE2 and a relative increase in LTB4, a potent chemoattractant and activator of polymorphonuclear leukocytes. These results suggest that inhibition of the cyclo-oxygenase pathway may be contraindicated in Pseudomonas keratitis; inhibition of lipoxygenase can prevent this worsening of the keratitis.

Topics: Administration, Topical; Animals; Corneal Ulcer; Dinoprostone; Disease Models, Animal; Eye Infections, Bacterial; Flurbiprofen; Leukotriene B4; Masoprocol; Pseudomonas Infections; Rabbits

Leukotrienes (LTs) have been implicated as mediators of the inflammation and ulceration associated with ulcerative colitis and Crohn's disease. In the present study, the effects of a novel, orally active inhibitor of LT synthesis (MK-886) were examined in a rat model of chronic colitis. Colitis was induced by intracolonic administration of trinitrobenzenesulfonic acid. Colonic LTB4 synthesis was measured after incubation of tissue samples in vitro and by in vivo equilibrium dialysis. A single dose of MK-886 (10 mg/kg) significantly inhibited colonic LTB4 synthesis for greater than 24 h. Daily treatment with this dose significantly reduced colonic damage, as assessed macroscopically and histologically, when the treatment was performed 2 h before induction of colitis and daily thereafter for 1 wk, but not when treatment was performed during the second week after induction of colitis. A less marked beneficial effect of MK-886 was observed when the pretreatment dose was excluded, suggesting a role for LTs in the early events of the inflammatory process. Inhibition of LT synthesis during the first 24 h after induction of colitis did not alter the extent of infiltration of neutrophils into the colon, as measured by tissue myeloperoxidase activity. Daily treatment with sulfasalazine (100 mg/kg po) either during the first or second week after induction of colitis did not significantly affect the rates of healing. At the dose used, sulfasalazine only produced a transient inhibition of colonic LTB4 synthesis. This study therefore demonstrates that a specific, orally active inhibitor of LT synthesis can significantly accelerate healing in this animal model of colitis when the treatment is performed during the early phase of the inflammatory response.

Topics: Administration, Oral; Animals; Colitis, Ulcerative; Colon; Disease Models, Animal; Indoles; Inflammation; Leukotriene B4; Male; Rats; Rats, Inbred Strains; Sulfasalazine; Trinitrobenzenesulfonic Acid

Mediator compounds such as bradykinin, arachidonic acid, and LT are released in the brain in conditions causing cerebral swelling. The potential of these compounds to enhance this process was studied in the infusion-induced model of brain edema. Cats subjected to chloralose anesthesia were infused with 400 microliters of artificial CSF into the right and left frontal white matter within 2.5 hr. CSF infused into the left hemisphere contained either bradykinin (40 microM), arachidonic acid (3 mM), LTB4 (15 microM), or LTC4 (16 microM), respectively. Evans blue was administered as blood-brain barrier indicator. Water content of gray and white matter was microgravimetrically determined in serial coronal brain slices. Infusion of CSF only led to an increase in water content from 69 to between 75% and 79%. Addition of bradykinin effectively enhanced the infusion edema but did not open the barrier to Evans blue. Arachidonic acid even more effectively led to an increase in water content and opened the barrier to Evans blue, in addition. Infusion of LT (LTB4, as well as LTC4) was not found to increase further the infusion edema and did not open the blood-brain barrier to Evans blue. It is concluded that the infusion edema model is suitable for studying the edema-enhancing potential of mediator compounds. Marked enhancement of vasogenic brain edema by bradykinin or arachidonic acid again demonstrates a pathophysiological function of these compounds as mediators of secondary brain damage, although LT are unlikely to be specifically involved in vasogenic edema formation.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Blood-Brain Barrier; Body Water; Bradykinin; Brain Chemistry; Brain Edema; Cats; Disease Models, Animal; Leukotriene B4; Solutions; SRS-A

The Watanabe heritable hyperlipidemic (WHHL) rabbit, an animal model for familial hypercholesterolemia, has a deficiency in low density lipoprotein (LDL) receptor binding and exhibits elevated plasma lipoprotein levels and spontaneous atherosclerosis. Since atherosclerotic plaque formation has a number of features in common with the inflammatory process, we have investigated the effect of dietary supplementation with an anti-inflammatory steroid (cortisone acetate, 5 mg daily for 3 months) on atherosclerosis using the WHHL rabbit as a model. Atherosclerotic plaque formation in cortisone-fed animals was reduced by about 60% compared to control WHHL rabbits. Steroid administration increased circulating cholesterol levels modestly and triglycerides were increased about 6-fold. While very low density lipoprotein (VLDL)-cholesterol was increased, LDL-cholesterol levels were decreased and the particle was more triglyceride-enriched as well as less dense. Steroid-fed animals also exhibited decreased platelet aggregation and increased aortic 15-lipoxygenase activity. The histological observations showed typical fibrous plaques in aortas of both control and cortisone-fed rabbits, with intima thickened by foamy macrophages and subcellular lipoproteinaceous debris covered by a fibrous cap. These findings thus indicate that steroids reduce the rate of plaque initiation or progression but do not significantly change the histological appearance of the lesion.

Topics: Animals; Arteriosclerosis; Cholesterol; Cortisone; Disease Models, Animal; Leukotriene B4; Rabbits

Topics: Animals; Disease Models, Animal; Glomerular Filtration Rate; Glomerulonephritis; Leukotriene B4; Neutrophils; Rats; SRS-A

Topics: Animals; Biological Assay; Disease Models, Animal; Enterocolitis, Pseudomembranous; In Vitro Techniques; Indomethacin; Intestinal Mucosa; Leukotriene B4; Male; N-Formylmethionine Leucyl-Phenylalanine; Perfusion; Prostaglandins; Rabbits; SRS-A; Thromboxane B2; Vascular Resistance

We studied the time course of chemotactic factor generation and inflammatory cell accumulation in the rabbit aspiration pneumonia model. Two major potent chemotactic factors, leukotriene B4 (LTB4) and C5a, in bronchoalveolar lavage fluid (BALF) were measured by radioimmunoassay, and cell analysis was also done. The level of LTB4 increased only in the early phase (2-6 h) after endotracheal acid instillation. The level of C5a increased gradually almost in parallel with the total protein level in BALF, and reached a maximum at 24 h. Neutrophil accumulation occurred early and reached a maximum at 24 h. In contrast, the number of alveolar macrophages increased from days 1 to 7. These findings suggest that the increases in LTB4 and C5a are responsible for accumulation of neutrophils and that C5a may be an important chemotactic factor for alveolar macrophage.

Topics: Animals; Bronchoalveolar Lavage Fluid; Cell Count; Chemotactic Factors; Complement C5; Complement C5a, des-Arginine; Disease Models, Animal; Hydrochloric Acid; Intubation, Intratracheal; Leukotriene B4; Macrophages; Neutrophils; Pneumonia, Aspiration; Proteins; Rabbits

Interleukin-1 (IL-1) mediates a number of immunologic and physiologic responses associated with inflammation. A new model to monitor the primary effects of IL-1 and potential inhibitors on inflammation has been developed, which involves unilateral injection of 300 U of highly purified recombinant human IL-1 in mouse ears. Ear thickness of IL-1 injected ears increased 7-10-fold 24 hr posttreatment, concomitant with a corresponding increase in myeloperoxidase activity, suggesting that neutrophil influx contributes to this response. Administration of nonsteroidal antiinflammatory drugs did not influence the IL-1 effect in vivo. Inhibition of phospholipase A2 activity ameliorated the IL-1 stimulated inflammation; treatment with 10 mg/kg dexamethaxone eliminated approximately 80% of increased myeloperoxidase activity compared to control values. This model provides a well-defined in vivo assay with which to quantify the systemic effects of compounds capable of altering the activity of IL-1, and the data suggest that this mechanism may explain the unique efficacy of steroids as antiinflammatories.

Topics: Animals; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Disease Models, Animal; Female; Inflammation; Interleukin-1; Leukotriene B4; Mice; Mice, Inbred BALB C; Neutrophils; Peroxidase; Recombinant Proteins; Steroids

Previous studies in burned patients have shown an early enhanced polymorphonuclear leucocyte (PMN) generating capacity for superoxide radical (O2.-), for the arachidonic acid (AA) lipoxygenase metabolite leukotriene B4 (LTB4) and for platelet activating factor-acether (PAF). These findings have been confirmed on a burn injury rabbit model. As we have suggested a pivotal role for an exaggerated initial (less than 36-48 h) neutrophil stimulation leading to a later (greater than 72 h) immuno-depression and anergy, we tried to modulate the early phase by drug therapy. A Ginkgo biloba extract (IPS200) injected i.v. in burned rabbits greatly reduced O2.- and LTB4 generation on A23187 challenge. IPS200 includes flavonoids and other polyphenols, inhibiting either arachidonic acid metabolism or PAF receptors, and may thus exert their modulating effect on PMN function in thermal injury.

Topics: Animals; Burns; Calcimycin; Disease Models, Animal; Diterpenes; Free Radicals; Ginkgolides; Lactones; Leukotriene B4; Male; Neutrophils; Platelet Activating Factor; Rabbits; Superoxides

A non-suppurative chronic arthritis was induced in the juvenile dog knee by intra-articular instillations with Carrageenan. Lipoxygenase products of arachidonic acid were separated from synovial fluid by reversed-phase high-performance liquid chromatography (RP-HPLC). After ten weeks we observed an accumulation of leukotriene B4 (LTB4) in synovial fluid in five out of six experimental knees (0.94 to 5.5 ng/ml), as judged by integrated optical density. Biological activity of LTB4 was confirmed by chemokinesis. LTB4 was not detected in control knees. The 15-lipoxygenase products, 15-hydroxyeicosatetraenoic acid (15-HETE) and 13-hydroxy-9,11-octadecadienoic acid (13-HODD), being inhibitors of 5-lipoxygenase, were found in relatively high levels in the control knees compared to the arthritic knees. The results denote LTB4 as a pro-inflammatory local mediator during carrageenan-induced arthritis; possibly, the decreased levels of 15-HETE and 13-HODD in the arthritic knees may have a regulatory function, thus facilitating LTB4 generation.

Topics: Animals; Arthritis; Carrageenan; Chemotaxis, Leukocyte; Chromatography, High Pressure Liquid; Disease Models, Animal; Dogs; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Linoleic Acids; Lipoxygenase; Synovial Fluid

Among the various inflammatory mediators of otitis media (OM), metabolites of arachidonic acid (AA) such as prostaglandins (PGs) and leukotrienes (LTs) appear to play an important role in the pathogenesis of otitis media. In an effort to investigate the role of AA metabolites on the pathogenesis of otitis media, concentrations of AA metabolites were measured in middle ear effusion (MEE) from human and paralleling animal models of otitis media and the effects of inhibitors of AA metabolism, antibiotics, and tympanostomy tube (TT) on the outcome of animal models of OM were studied. Concentrations of AA metabolites in MEE were higher in the younger age group. Levels of PGE2 and LTB4 in MEE seem to represent the degree of inflammation of OM best. Lipoxygenase products seem to be associated with the mucoid type of MEE. In the study of animal models of OM, combined models and ears with TT showed more inflammation than single models and ears without TT. Study of the therapeutic use of inhibitors of AA metabolism, penicillin, and TT showed that lipoxygenase products may be more important in the pathogenesis of OM than the cyclo-oxygenase products, and that the use of a combination of penicillin and corticosteroid produces the best results. It is clear from these studies that arachidonic acid metabolites are important inflammatory mediators in the pathogenesis of otitis media.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acids; Chinchilla; Dinoprostone; Disease Models, Animal; Humans; Hydrocortisone; Hydroxyeicosatetraenoic Acids; Ibuprofen; Leukotriene B4; Middle Ear Ventilation; Otitis Media with Effusion; Penicillin G; Prostaglandins; Prostaglandins E; SRS-A; Temporal Bone; Thromboxane B2

Necrotizing enterocolitis (NEC) was produced in anesthetized rabbits by transmural injection of intestinal loops with an acidified solution of casein and calcium gluconate, mimicking the luminal milieu of afflicted neonates. Intravenous infusion of superoxide dismutase (SOD) 15 min after NEC induction prevented intestinal damage. In ex vivo perfused intestinal loops, we determined the sites of eicosanoid release and their contribution to the vascular effects of N-formyl-methionyl-leucyl-phenylalanine (fMLP) and platelet-activating factor (PAF) in damaged and SOD-salvaged intestine. The vascular effluent was the primary site of stimulated eicosanoid release. The vascular responses to fMLP (vasoconstriction) and PAF (vasodilation) were not altered by SOD, although vascular resistance was higher in the SOD group. SOD treatment attenuated 1) transmural fluid shifts in ex vivo perfused intestinal preparations, an index of vascular permeability, 2) fMLP-induced prostaglandin E2, 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), and leukotriene B4 (LTB4) release, and 3) PAF-induced release of 6-keto-PGF1 alpha and LTB4. Stimulated thromboxane B2 release was not altered by SOD. Thus NEC can be established by a luminal insult that causes local generation of free radicals and exaggerated release of prostaglandins and leukotrienes.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Depression, Chemical; Dinoprostone; Disease Models, Animal; Enterocolitis, Pseudomembranous; Leukotriene B4; Leukotrienes; Male; N-Formylmethionine Leucyl-Phenylalanine; Platelet Activating Factor; Prostaglandins; Rabbits; Superoxide Dismutase; Thromboxane B2

Inflammation induced by systemic injection of endotoxin can be a good model for endogenous uveitis since ocular inflammation is induced without manipulating the eye. We carried out morphological and biochemical studies in Lewis rats to evaluate the breakdown of the blood-ocular barrier following injection of endotoxin (1 mg/rat) in footpads. Vasodilation was observed as early as 3 hours and became maximum at 18-24 hours after the injection. Unlike in the eye, no inflammatory changes were observed in other organs. Protein and cell contents in the aqueous humor increased significantly as early as 3 hours after the injection and reached a peak level at 24 hours. The protein content returned to the normal level in the following several days, while cells in the aqueous humor remained at a high level even 1 week after the injection. The time-course of the pupillary size was very similar to that of the protein concentration. Furthermore, we examined leukotrienes (LTs) levels in aqueous humor by high-pressure liquid chromatography. LTD4 was detected in the aqueous humor at 6 hours and reached its peak level at 24 hours. The present data indicates that the systemic injection of endotoxin causes the disruption of the blood-ocular barrier soon after the injection and inflammation becomes maximum in 18-24 hours. This model can be used for studying endogenous uveitis and the disruption of the blood-ocular barrier without direct trauma to the eye.

Topics: Animals; Aqueous Humor; Chromatography, High Pressure Liquid; Disease Models, Animal; Dose-Response Relationship, Immunologic; Endotoxins; Injections; Leukotriene B4; Male; Rats; Rats, Inbred Lew; Retina; Shigella flexneri; Time Factors; Uveitis; Uveitis, Anterior

Using the bilateral carotid artery occlusion model of cerebral ischemia in the gerbil, we studied the effect of moderate hypothermia (30 to 31 degrees C) on the postischemic production of prostanoids (cyclooxygenase pathway) and leukotrienes (lipoxygenase pathway) and accompanying changes in cerebral edema formation. Hypothermia capable of slowing central evoked potential conduction time was studied over the course of 40 minutes of cerebral ischemia and for up to 2 hours of reperfusion. The successful induction of cerebral ischemia was confirmed by somatosensory evoked potential amplitude changes. Measurements of 6-ketoprostaglandin F1 alpha (PGF1 alpha) and leukotriene B4 (LTB4) (radioimmunoassay) and cerebral edema (specific gravity) were made at early (10 minutes) and late (2 hours) reperfusion times. Although both white and gray matter showed no early significant difference in edema accumulation between normothermic and hypothermic gerbils at 10 minutes of reperfusion, hypothermic animals demonstrated significantly less white matter edema (specific gravity, 1.0397 +/- 0.0010 vs. 1.0341 +/- 0.0012, P less than 0.01) and gray matter edema (specific gravity, 1.0408 +/- 0.0009 vs. 1.0365 +/- 0.0008, P less than 0.01) by 2 hours of reperfusion. Production of PGF1 alpha was not significantly different between normothermic and hypothermic animals during the reperfusion period; however, hypothermic gerbils demonstrated significantly lower production of LTB4 at 10 minutes reperfusion time compared to normothermic animals (1.49 +/- 0.79 vs. 5.28 +/- 1.49 pg/mg of protein, P less than 0.05). This difference between the two groups in LTB4 levels was no longer detectable at 2 hours of reperfusion time.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Brain Edema; Disease Models, Animal; Evoked Potentials, Somatosensory; Gerbillinae; Hypothermia; Ischemic Attack, Transient; Leukotriene B4; Male; Prostaglandins F

Two experimental models of acute non-immune inflammation have been developed to enable studies of the biochemical composition and cellular content of exudates to be undertaken. Both are based on the creation of a mild, reproducible and reversible inflammatory reaction, which is free from uncontrolled incidental factors and which causes minimal distress to the experimental animals. The polyester sponge model involves the insertion of small polyester sponge strips soaked in sterile carrageenan solution into subcutaneous neck pouches and their serial removal. The tissue-cage model is based on the initial insertion of a spherical tissue-cage subcutaneously in the neck and the subsequent stimulation with carrageenan of the granulation tissue which lines and permeates the cage. The acute inflammatory exudates have been shown to contain eicosanoids with prostaglandin E2 predominant. Polymorphonuclear leucocyte numbers increased progressively in the polyester sponge model, whereas cell numbers were maximal at 12 hours in the tissue-cage model. The relationships between eicosanoid formation at the site of inflammation and leucocyte accumulation, enzyme release, total protein content of exudates and the temperature of the lesions have been investigated.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Carrageenan; Dinoprostone; Disease Models, Animal; Exudates and Transudates; Horse Diseases; Horses; Inflammation; Leukotriene B4; Prostaglandins E; Proteins; Thromboxane B2

Arachidonic acid-induced pleurisy in the rat was evaluated for testing inhibitors of arachidonic acid (AA) metabolism. The model involves the administration of AA intrapleurally and the determination of LTB4 and PGE2 as indicators of 5-lipoxygenase and cyclooxygenase activities in the exudate/wash. This model is suitable for the in vivo evaluation of potential inhibitors of the 5-lipoxygenase pathway but not the cyclooxygenase pathway of AA cascade.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Arachidonate Lipoxygenases; Arachidonic Acids; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Indomethacin; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Prostaglandins E; Pyrazoles; Rats; Rats, Inbred Strains; Time Factors

Monosodium urate (MSU) and calcium pyrophosphate dihydrate (CPPD) crystals initiated acute inflammatory reactions characterized by increased plasma extravasation and polymorphonuclear leukocyte (PMNL) accumulation in the rat subcutaneous air-pouch. Pretreatment of rats with colchicine (1 mg kg-1, s.c.) inhibited PMNL accumulation induced by either crystal type but had a greater inhibitory effect on MSU-induced plasma extravasation compared with that induced by CPPD crystals. Colchicine (1 mg kg-1, s.c.) did not reduce histamine-induced plasma extravasation in the air-pouch. The lipoxygenase product of arachidonic acid metabolism, leukotriene B4 (LTB4), was detected in MSU-induced exudates but not in CPPD-induced exudates. Pretreatment of rats with colchicine (1 mg kg-1, s.c.) inhibited LTB4 production in MSU-induced exudates.

Topics: Animals; Anti-Inflammatory Agents; Calcium Pyrophosphate; Colchicine; Diphosphates; Disease Models, Animal; Inflammation; Leukotriene B4; Male; Neutrophils; Rats; Rats, Inbred Strains; Uric Acid

An equine model of acute non-immune inflammation has been developed to facilitate studies of the inflammatory process and the actions of novel anti-inflammatory drugs. Five polyester sponge strips soaked in sterile 2% carrageenin solution were placed in subcutaneous pouches prepared under local anaesthesia in the necks of conscious ponies. Serial removal of the strips and harvesting of the exudate enabled studies to be made of the cellular, biochemical and mediator aspects of the localised, acute inflammation, and the heat generated by the lesion was monitored by infra-red thermometry. Maximal concentrations of the eicosanoids 6-keto-prostaglandin F1 alpha, thromboxane B2 and leukotriene B4 occurred at 9 h, whereas leukocyte numbers, lactate dehydrogenase (LDH) and total protein concentrations were greatest at 24 h. Lesional skin temperature was increased by approximately 4 degrees C throughout the 24 h period. The novel anti-inflammatory agent BW540C, administered orally at a dose-rate of 20 mg/kg, did not affect leukocyte infiltration or the concentrations of protein, LDH and eicosanoids in exudate but serum thromboxane B2 levels were reduced. Skin temperature rises were greater in drug-treated animals. It is concluded that higher doses of BW540C will be required for a clinically useful anti-inflammatory action in horses.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Disease Models, Animal; Exudates and Transudates; Female; Horse Diseases; Horses; Inflammation; L-Lactate Dehydrogenase; Leukocyte Count; Leukotriene B4; Proteins; Pyrazoles; Skin Temperature; Thromboxane B2

Topics: Animals; Anti-Inflammatory Agents; Disease Models, Animal; Inflammation; Leukotriene B4; Receptors, Drug

Rat IgE pleurisy was induced by the injection of di-nitrophenol-conjugated bovine serum albumin (DNP-BSA) 48 hours after the intrapleural injection of rat anti-DNP-IgE serum. IgG-BSA complex pleurisy was also induced by the intrapleural injection of IgG-BSA complexes produced at the optimum ratio in vitro. Plasma exudation was markedly increased in the first 20 minutes, but not observed thereafter, in IgE pleurisy, whereas marked plasma exudation in the first 20 minutes was followed by weak exudation at three and five hours in IgG-BSA complex pleurisy. Leukotrienes (LTs) E4 (100 ng/rat), D4 (32) and B4 (16) were detected on HPLC in the pleural exudate in the first 20 minutes of IgG-BSA complex pleurisy, but less (9 ng/rat) LTE4 alone was detected in the five-hour exudate. The first 20-minute pleural exudate contained 13 ng/rat of LTE4 in IgE pleurisy. The plasma was completely inhibited by simultaneous treatment of rats with pyrilamine (2.5 mg/kg, i.p.) and methysergide (3 mg/kg, i.p.), as it was in compound 48/80-induced pleurisy. In IgG-BSA complex pleurisy, 90% of the pleural exudate for the first 20 minutes was inhibited by the same treatment, and the rest was completely suppressed by simultaneous treatment with an intrapleural injection of AA-1777, a selective 5-lipoxygenase inhibitor. AA-1777 alone did not reduce the plasma exudation significantly. The 5-lipoxygenase inhibitor was also very effective in reducing the migrating numbers of polymorphonuclear and mononuclear leukocytes to half, without affecting the eosinophils of mast cells.

Topics: Animals; Antigen-Antibody Complex; Benzoquinones; Chemotaxis, Leukocyte; Chromatography, High Pressure Liquid; Disease Models, Animal; Exudates and Transudates; Immunoglobulin E; Immunoglobulin G; Leukotriene B4; Leukotriene E4; Lipoxygenase Inhibitors; Methysergide; Pleurisy; Pyrilamine; Quinones; Rats; Rats, Inbred Strains; Receptors, Histamine; Receptors, Serotonin; Respiratory Hypersensitivity; SRS-A

Streptococcal cell wall fragments, suspended in phosphate-buffered saline, were injected into a preformed subcutaneous air pouch in rats. The advantage of the air pouch model is the capacity for quantitation of exudative, cellular, and proliferative responses and soluble mediators. Accumulation of pouch fluid containing many leukocytes occurred during the first 3 days. Granulation tissue separable from the surrounding subcutaneous tissue developed by 6 days. Immunofluorescence and immunoperoxidase staining showed the presence of cell walls in inflammatory cells both in pouch fluid and in pouch tissue. Histologic features of this inflammation included an acute exudative phase with a predominantly neutrophil infiltration followed by a chronic phase characterized by fibroblast proliferation, formation of blood vessels, and infiltration with mononuclear cells. The lining of the pouch before injection of cell wall developed morphologic features of synovial membrane, which became more evident during the chronic phase of induced inflammation. Outbred Sprague-Dawley and inbred Lewis rats developed more pouch fluid, cell numbers in the pouch fluid, and granulation tissue than inbred Buffalo rats. The arachidonic acid metabolites, prostaglandin E2 and leukotriene B4, were measured in the pouch fluid, and more of each was produced in the Lewis than in the Buffalo strain. These measurements of inflammation are consistent with the relative susceptibility of these strains to cell-wall-induced arthritis. This model of inflammation can be used in the examination of the regulatory mechanisms of evolving chronic inflammation.

Topics: Animals; Cell Wall; Dinoprostone; Disease Models, Animal; Inflammation; Leukotriene B4; Prostaglandins E; Rats; Rats, Inbred BUF; Rats, Inbred Lew; Species Specificity; Streptococcus pyogenes; Time Factors

Topics: Animals; Anti-Inflammatory Agents; Dinoprostone; Disease Models, Animal; Inflammation; Leukocyte Count; Leukotriene B4; Propionates; Prostaglandins E; Rats; Thromboxane B2

Topics: Animals; Carrageenan; Disease Models, Animal; Exudates and Transudates; Horse Diseases; Horses; Inflammation; Leukotriene B4; Neutrophils; Rats