[Effects of p38 mitogen-activated protein kinase in rats with oleic acid-induced acute lung injury].

OBJECTIVE: To study the effects of p38 mitogen-activated protein kinase (p38MAPK) signal transduction pathway inhibitor SB203580 on the inflammatory reaction and lung water clearance, and to explore the role of p38MAPK in acute lung injury, to provide new way for p38MAPK inhibitor -SB203580 intervene fat embolism syndrome induced lung injury. METHODS: Twenty-four adult male SD rats were randomly assigned to normal control group (OA group) (n=8), oleic acid-induced lung injury group (OA group, n=8)and SB203580 pretreatment group (n=8). OA-group was administered oleic acid (0.20 ml/kg) via right jugular vein; In SB203580-group, SB203580(5 mg/kg) was injected via jugular vein, followed 30 min before by OA infusion; At the 4 hours animals were sacrificed. Arterial blood gas, the wet/dry weight(W/D)of the right lower lung were examined, lung index(LI), pulmonary permeability index(PPI) and levels of tumor necrosis factor α(TNF-α) in bronchoalveolar lavage fluid(BALF) were examined. The expressions of p38MAPK and phospho-p38MAPK (p-p38MAPK) were determined by Western blot and immunohistochemical method. Pathological changes of the lung tissue were examined with light microscrope. RESULTS: Compared to control group, arterial oxygen partial pressure (PaO2) and PaO2/FiO2 were decreased in the animals of OA-group, while right lower lung wet/dry ratio, lung index, PPI, levels of TNF-α in BALF and the protein expression of p-p38MAPK were increased significantly (P<0.01). The pathological changes were observed significantly in injured lung tissue. Compared to OA-group, those indexes were improved in SB203580 pretreated group. CONCLUSIONS: p38MAPK signal transaction path mediated inflammatory response process and played an important role in acute lung injury. SB203580 could inhibit the expression of inflammatory cytokines, reduce lung edema, protect lung tissue of rats from OA-induced lung injury obviously. Therefore, inhibition of p38MAPK activity provides a new way for the clinical treatment of fat embolism syndrome induced lung injury.