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Type: Artigo de periódico
Title: Acute Pulmonary Inflammation Induced By Exposure Of The Airways To Staphylococcal Enterotoxin Type B In Rats.
Author: Desouza, Ivani A
Franco-Penteado, Carla F
Camargo, Enilton A
Lima, Carmen S P
Teixeira, Simone A
Muscará, Marcelo N
De Nucci, Gilberto
Antunes, Edson
Abstract: Staphylococcus aureus is a gram-positive bacterium that produces several enterotoxins, which are responsible for most part of pathological conditions associated to staphylococcal infections, including lung inflammation. This study aimed to investigate the underlying inflammatory mechanisms involved in leukocyte recruitment in rats exposed to staphylococcal enterotoxin B (SEB). Rats were anesthetized with pentobarbital sodium and intratracheally injected with either SEB or sterile phosphate-buffered saline (PBS, 0.4 ml). Airways exposition to SEB (7.5-250 ng/trachea) caused a dose- and time-dependent neutrophil accumulation in BAL fluid, the maximal effects of which were observed at 4 h post-SEB exposure (250 ng/trachea). Eosinophils were virtually absent in BAL fluid, whereas mononuclear cell counts increased only at 24 h post-SEB. Significant elevations of granulocytes in bone marrow (mature and immature forms) and peripheral blood have also been detected. In BAL fluid, marked elevations in the levels of lipid mediators (LTB(4) and PGE(2)) and cytokines (TNF-alpha, IL-6 and IL-10) were observed after SEB instillation. The SEB-induced neutrophil accumulation in BAL fluid was reduced by pretreatment with dexamethasone (0.5 mg/kg), the COX-2 inhibitor celecoxib (3 mg/kg), the selective iNOS inhibitor compound 1400 W (5 mg/kg) and the lipoxygenase inhibitor AA-861 (200 microg/kg). In separate experiments carried out with rat isolated peripheral neutrophils, SEB failed to induce neutrophil adhesion to serum-coated plates and chemotaxis. In conclusion, rat airways exposition to SEB causes a neutrophil-dependent lung inflammation at 4 h as result of the release of proinflammatory (NO, PGE(2), LTB(4), TNF-alpha, IL-6) and anti-inflammatory mediators (IL-10).
Subject: Acute Disease
Anti-inflammatory Agents
Bone Marrow
Bronchoalveolar Lavage Fluid
Chemotaxis, Leukocyte
Dose-response Relationship, Immunologic
Intubation, Intratracheal
Leukocyte Count
Leukotriene B4
Lipoxygenase Inhibitors
Pneumonia, Staphylococcal
Rats, Wistar
Time Factors
Citation: Toxicology And Applied Pharmacology. v. 217, n. 1, p. 107-13, 2006-Nov.
Rights: fechado
Identifier DOI: 10.1016/j.taap.2006.07.001
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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