Objective To investigate the effect of trimetazidine postconditoning on myocardial cell apoptosis in acute ischemia-reperfusion injury in rats.Methods 40 healthy adult Wistar rats were randomly assigned to Sham-operated group,MIRI group(I/R group),trimetazidine group and ischemic postconditioning group(IPOC group).The left anterior descending coronary artery of rat was ligated and the acute myocardial ischemia-reperfusion injury model was established.After that,ultrastructural changes of apoptotic myocardial cells were observed under electron microscope,and apoptotic cells were detected under optical microscope.The expressions of the Bcl-2,caspase-3 apoptosis related proteins were determined.Results ① The degree of ultrastructural injury of apoptotic myocardial cells was mild and basically the same in trimetazidine group versus IPOC group,and had a significant improvement as compared with I/R group.② The degree of myocardial apoptosis was basically the same in trimetazidine versus IPOC group,and lighter than in I/R group.③ Bcl-2 protein expression levels were(61.9 ± 2.9) ％,(21.4 ± 3.2) ％,(46.8 ± 3.5) ％ and (49.7 ± 3.1) ％,and caspase-3 protein expression levels were(38.1±4.5) ％,(72.8±5.7) ％,(47.2±5.1) ％ and(39.8 ±4.6)％ in Sham-operated group,I/R group,trimetazidine group and IPOC group respectively.Compared with I/R group,the expression of Bcl-2 protein was increased obviously,while the expression of easpase-3 protein was decreased in trimetazidine group and IPOC group.But there were no significant differences in the protein levels of Bcl-2 and caspase-3 between trimetazidine group and IPOC group(both P＞0.05).Conclusions Trimetazidine postconditoning can inhibit the myocardial cell apoptosis in acute ischemia-reperfusion injury in rats,and has a protective effect on myocardial cells.