Effects of insulin-like growth factor-1 on cell apoptosis in lung tissue of rats with severe acute pancreatitis

AIM: To explore the roles of cell apoptosis and expression of bax and bcl-2 in lung tissue in the mechanism of lung injury induced by severe acute pancreatitis (SAP) and the effects of insulin-like growth factor-1(IGF-1) on cell apoptosis in lung tissue of rats with SAP. METHODS: Wistar rats were randomly divided into three groups: Control group (n=24), SAP group (n=24) and IGF-1 group (n=24). Every group was randomly divided into 3 time units (6,12,24 h), with 8 rats in each time unit. The models of SAP were established by retro-grade injection of 50 g/L sodium taurocholate solution into the bilio-pancrestic duct of rats. At the 6,12 and 24 h after establishment of models, serum amylase, histologic scoring of lung injury were determined. The lung tissue was taken for light and transmission electron microscopic observation. Cell apoptosis in lung tissue was determined by TUNEL method, the expressions of bax mRNA and bcl-2 mRNA were detected by RT-PCR. RESULTS: In the SAP group, serum amylase, histologic scoring of lung injury, apoptotic index, the expressions of bax mRNA and bcl-2 mRNA markedly increased. Apoptotic cells increased obviously under transmission electron microscope. As compared with SAP group at the same phase, serum amylase, histologic scoring of lung injury, apoptotic index, expressions of bax mRNA in IGF-1 group decreased significantl, while the expression of bcl-2 mRNA increased significantly. Apoptotic cells decreased obviously in transmission electron microscopic observation. CONCLUSION: The apoptosis and expression of bax and bcl-2 in lung tissue might be involved in pathogenesis of the lung injury induced by SAP. IGF-1 can alleviate the lung injury by inhibiting apoptosis of lung tissue cells, in which its effects on regulating the expression of bax and bcl-2 may play an important role.