Abstract: Objective:To establish the rat acute myocardial ischemia/reperfusion model using capsule and observe the protective effects of ischemic postconditioning(IPost) on rats.Methods:Thirty-six rats were randomly divided into sham operation group,ischemia/reperfusion group(I/R group) and Ipost group(12 rats in each group),and all animals were sacrificed at the end of reperfusion.The cardiac functional parameters,plasma myocardial enzymes,apoptosis index and the scope of myocardial infarct were determined,and the levels of Bcl-2,Bax,Caspase-3 of cardiac muscular tissue were detected by Western blot.Results:Compared with I/R group,the cardiac functional parameters of Ipost group were obviously improved(P0.01),while their plasma myocardial enzymes,apoptosis index were significantly lower and scopes of myocardial infarct were significantly less(P0.05).The level of Bcl-2 of Ipost group was significantly higher than that of the I/R group,and the levels of Bax and Caspase-3 of Ipost group were significantly lower than those of the I/R group(P0.01).Conclusions:The method of ligating coronary artery with capsule is fast and convenient for Ipost,which can alleviate myocardial ischemia/reperfusion injury,reduce myocardial cells apoptosis and downsize the scope of myocardial infarct.The protective mechanism is possible associated with the activation of RISK signaling pathway.