Effects of ischemic postconditioning on cardiomyocyte apoptosis and expression of Bcl-2 and Bax protein after ischemia and reperfusion in rabbits

Aim:To elucidate the effects of ischemic postconditioning on myocardial cell apoptosis and expressions of Bcl-2 and Bax protein after ischemia and reperfusion in rabbits.Methods:Rabbits were randomized into 4 groups: sham operation group(Group S):only braid,with no occlusion;ischemia and reperfusion group(Group IR):left anterior descending(LAD) occlusion and reperfusion,with no other intervention; myocardial ischemic preconditioning(Group IP):3 cycles of myocardial ischemia (5 min) and reperfusion(5 min) preceded the ischemia and reperfusion protocol;myocardial ischemic postconditioning(Group IPO): 6 postconditioning cycles of 10 s reperfusion and 10 s ischemia after the coronary occlusion (30 min),then reperfusion for 120 min. Cardiomyocyte apoptosis was determined by TUNEL,and the expressions of Bcl-2 and Bax protein in the myocardium of ischemic area were measured by immunohistochemical technique.Results: Compared with those in the Group IR, cardiomyocyte apoptosis index was significantly reduced and the ratio of Bcl-2 to Bax were increased in both Group IP and Group IPO.No significant difference was found between Group IP and Group IPO(P0.05).Conclusion: Ischemic postconditioning,like ischemic preconditioning,exerts an anti-apoptotic effect,which may associate with regulating the expressions of Bcl-2 and Bax protein.