RESUMO
Objective To investigate the effects, and possible mechanism of action, of vasoactive intestinal peptide (VIP) on acute lung injury in a rodent model of endotoxic shock. Method Endotoxic shock was induced in Sprague-Dawley (SD) rats by intravenous injection of lipopolysacchaiide (LPS) at 10 mg/kg. Three groups (each group with 10 rats), were given injections of either normal saline (Control), LPS 10 mg/kg (LPS group), or LPS 10 mg/kg + VIP 5nmol (VIP). Samples were collected 6 hours after injection. Indices of lung injury including lung wet/dry weight ratio, protein concentration and neutrophil count in bronchoalveolar lavage fluid( BALF) were derived. Assays of TNF-α,IL-1β, IL-10 in serum and BALF were performed using ELISA. Light and electron microscopy were used to detect histopathological changes in lung tissues. Results The lung wet/dry weight ratio, protein concentration and neutrophil count in BALF were significantly raised in the LPS group compared to the Control group (P ＜ 0.05). These indices were significantly lowered in the VIP group compared to the LPS group, though not to the level of the control group. Concentrations of TNF-α, IL-1β, IL-10 in serum and BLAF also increased in the LPS group compared to the control group (P ＜ 0.0S). Levels of TNF-α and IL-1β were significantly lowered in the VTP group compared to the LPS group (P ＜ 0.05), while levels of IL-10 was significantly raised ( P ＜ 0.05). Histopathological changes due to lung injury were not as severe in the VIP group compared to the LPS group. CondusKms VIP plays a protective role during acute lung injury induced by endotoxic shock in rats. Its mechanism of action may be related to down-regulation of proinflammatory cytokines and up-regulation of anti inflammatory cytokines.