Abstract: AIM:To study ischemia/reperfusion on myocardial protein expression of apoptosis and the role of pinacidil, an ATP-sensitive potassium channel opener. METHODS: Twenty four adult male Wistar rats were randomly divided into control group, ischemia/reperfusion group, pinacidil ischemic postconditioning group and glibenclamide treatment group (n=6, each). Using immunohistochemistry and image analysis techniques, quantitative analysis was conducted on ischemia/reperfusion in rats given pinacidil after the treatment and early apoptosis protein expression changes of Bax, Bcl-2 and FN. RESULTS: The apoptosis protein expression (Bax, FN) increased during anoxia/reperfusion, whereas Bcl-2 protein expression decreased. Pinacidil ischemic postconditioning treated Bax, FN protein expression decreased, whereas Bcl-2 protein expression increased. Optical density value of each group showed significant differences (P<0.05). CONCLUSION: Pinacidil has an anti-apoptotic function, and pinacidil ischemic postconditioning exerts a cardioprotective effect in acute myocardial ischemia/reperfusion injury.