Effect Of Ischemic Postconditioning On Bcl-2,Bax Protein Expression In Rat Liver Cells After Ischemic Reperfusion

Objective To investigate the effect of ischemic postconditioning on Bcl-2,Bax expression in liver cells and access the possible mechanism after ischemic reperfusion。Methods Fourty-five healty male SD rats weighing 180-230 g were randomly divided into 3 groups:sham-operated(S group),ischemia-repeffusion(IR group)and post-ischemia conditioning(IPo group)with 15 rats in each group,The model of partial hepatic ischemia was established in SD rats,In group IPo rat liver were subjected to six episodes of 10 second ischemia at 10s interval before persistent reperfusion.Blood samples of each group were collected from the inferior cava vena at 2,4 and 6 h after reperfusion and the serum levels of AST and ALT were detected.Mitochondrial super oxidedismutase(SOD), malondialdehyde(MDA)in samples of liver tissue were detected,and the mitochondrial ultrastructure was observed with electonmicroscope.The expression of Bcl-2 and Bax gene protein in the liver tissues were detected by immunohistochemical.Results 1.Compared with the IR group,at every time point,the contents of ALT,AST in serum in IPo group decreased(P＜0.01).2.Compared with the IR group,at every time point,the concentrations of MDA in hepatic tissue in IPo group decreased(P＜0.01),while the concentrations of SOD increased significantly(P＜0.05).3.The histologic changes of the liver tissue under electronic microscopies was more obvious in the group IR than in the group IPo at 2,4,6 h of reperfusion.4.The expression of protein Bax in the group IPo was lower than in the ischemia group (P＜0.01);the expression of protein Bcl-2 in the group IPo was higher than in the ischemia group(P＜0.01).Conclusion Bcl-2,Bax expression may be involved in the process of liver cell apoptosis and liver ischemia reperfusion injury;Ischemic postconditioning cound lessen ischemic reperfusion injury by reducing the rates of liver apoptosis,up-regulating Bcl-2 and down-regulating Bax.