[Effects of Shenmai injection on the expression of p38MAPK and the apoptosis-related genes in lung injury induced by intestinal ischemia/reperfusion in rats].

Objective: To observe the effects of Shenmai injection(SM) on p38MAPK and the apoptosis-related genes in lung injury induced by intestinal ischemia reperfusion (I/R) in rats and to investigate the protective mechanism of SM.
Methods: Rat model of intestinal I/R injury was established with clamping of the superior mesenteric artery (SMA) for 60 min and then clamping was relieved for 60 min. Twenty-four SD rats were randomly divided into three groups with eight rats in each: control group, intestinal ischemia/reperfusion group(I/R group), Shenmai injection treated group (SM+I/R group). Lung wet/dry weight ratio(W/D), the contents of phosphatidylcholine (PC) and total phospholipid(TPL) which are the major ingredients of pulmonary surfactant were measured, as well as the expression levels of p38MAPK, Bcl-2 and Bax proteins in lung tissue were examined by using immunohistochemical method.
Results: Compared with control group, lung W/D was significantly increased, the contents of PC and TPL were significantly decreased, the protein expression levels of p38MAPK, Bcl-2 and Bax were significantly increased in I/R group (all P＜0.01). But Bax protein expression was much greater than Bcl-2 protein expression, the ratio of Bcl-2 to Bax were significantly decreased in I/R group than that in control group (P＜0.01). Compared with I/R group, lung W/D was significantly decreased, while the contents of PC and TPL were significantly increased, the p38MAPK and Bax protein expression levels were significantly decreased in SM+I/R group (all P＜0.01); both Bcl-2 protein expression and the ratio of Bcl-2 to Bax were significantly increased in SM+I/R group than those in I/R group (P＜0.01). The correlation analysis indicated that the expression level of p38MAPK protein in lung tissue was negatively correlated with the contents of PC and the ratio of Bcl-2 to Bax (r is -0.787 and -0.731, all P＜0.01).
Conclusion: SM can protect the lung injury induced by intestinal I/R injury, which may be mediated by inhibiting the activation of p38MAPK, improving the ratio of Bcl-2 to Bax to inhibit lung apoptosis.