Effects of ischemic postconditioning on myocardial cell during ischemia/reperfusion period in rabbits

Objective To investigate the effects of ischemic postconditioning (Post) on myocardial cell apoptosis and expres- sion of Bcl-2 and Bax protein during ischemia/reperfusion period in rabbits.Methods Eighteen rabbits were randomly allocated to three groups (6 in each group),sham operation (group S),ischemia/reperfusion group(group IR) and ischemic postconditioning group(group Post).Group IR and group Post were subjected to 15 minutes of left anterior descending coronary artery occlusion followed for 30 minutes of reperfusion.Ischemic postconditioning was achieved by three 30 seconds cycles of reperfusion,each followed by 30 seconds ischemia.Cardiomyocyte apoptosis were determined by in situ TDT-mediated dUTP nick end labeling (TUNEL) and DNA electrophoresis.The expression of Bcl-2 and Bax proteins in apoptotic myocardial cells were detected by immunohistochemistry sepa- rately.Results Compared with group IR,apoptotic index was significantly reduced in group Post [(28.06±2.92) % vs.(55.70± 13.96)%,P0.01].Bcl-2 expression was higher in group Post than that in group IR(10,00±0.89 vs.7.83±1.47,P0.05), while Bax expression was lower in Group Post than that in group IR (7.50±0.84 vs.9.83±0.98,P0.05).Conclusion Con- clusion Ischemic postconditioning can lower the ratio of apoptosis and protect myocardial cells from IR injury by increasing Bcl-2 ex- pression and decreasing Bax expression.