Diazoxide reduces rabbit myocardial apoptosis induced by ischemia-reperfusion injury

Objective To investigate the effects of diazoxide on myocardial apoptosis, and bcl-2 and bax gene expressions during ischemia-reperfusion period in rabbits. Methods Twenty-four rabbits were randomly divided into pseudo-operation group (Group P), ischemia-reperfusion group (Group IR), ischemic preconditioning group (Group IP) and diazoxide group (Group DP). The left anterior descending coronary arteries were ligated and then unclamped to establish ischemia-reperfusion injury model. The ischemic preconditioning was induced by three cycles of 5 minute ischemia/5 minute reperfusion. In Group DP, the rabbits were pretreated intravenously with diazoxide (3 mg/kg). After reperfusion, the infarct sizes of left ventricular myocardium were calculated. Apoptotic myocardial cells were detected by TdT-mediated dUTP nick end labeling (TUNEL). The expressions of bcl-2 and bax protein were measured by immunohistochemical technique in the myocardium of ischemic area. Results Infarct sizes in group DP and group IP were markedly less than that in Group IR (P0.001). The percentage of apoptotic cells in Group DP(34±5%) and Group IP (32±6)% were reduced markedly as compared with Group IR[(56±8)%, P0.001]. The expressions of bcl-2 in Group IP and Group DP were increased as compared with Group IR (P0.01,in both), whereas the expressions of bax in Group IP and Group DP were decreased as compared with Group IR (P0.001). Conclusion Diazoxide can reduce rabbit myocardial apoptosis induced by ischemia-reperfusion injury through regulating the expressions of bcl-2 and bax gene.