Impact and significance of hypoxia preconditioning on the expression of Bcl-2 protein in orthotopic liver autotransplantation in rats

Objective To explore the impact and significance of hypoxia preconditioning on the expression of Bcl-2 protein after orthotopic liver autotransplantation in rats.Methods A modified orthopotic liver autotransplantation model was used to study the ischemia reperfusion injury in liver transplantation.Sprague-Dawley rats were randomly divided into the following three groups: normal control(NC) group,autotransplantation(AT) group,and hypoxia preconditioning(HP) group,there were twenty four rats in each group.HP Group was given an 8% oxygen-mixed gas for 90 minutes before the operation.At 1,6,and 24 hours after the operation,the rats were killed and the following tests were conducted:(1)Liver tissue was sampled to observe the expression of Bcl-2 protein;(2)blood was drawn to conduct a chemical examination;(3) morphology was observed by light microscopy and transmission electron microscopy;(4)chondrosomes were quantitatively analysed by a MiVnt image analysis system.Results The serum levels of ALT and AST in HP group were significantly lower than that of AT group(P0.05) at 1,6 and 24 hours after the orthopotic liver autotransplantation.The expression of Bcl-2 protein was increased significantly(P0.05) in HP group at each measurement point.The hepatic tissues in HP group were less swollen than AT group under light microscopy.Hepatic cells in AT group showed typical apoptosis signs under transmission electron microscopy(TEM),but no apoptosis was found in HP group.The appearance of hepatocytes in HP group was much better than AT group,and the areas,perimeters and diameters of chondrosomes in group HP under TEM were much smaller than that in AT group(P0.05).Conclusions HP has marked inhibition to apoptosis by up-regulating the expression of Bcl-2 protein and protection to chondrosomes after an orthopotic liver autotransplantation.