Protective effect of different concentration diazoxide against ischemia/reperfusion in rabbit hearts

Objective To investigate the protective effect of mitochondrial ATP sensitive potassium(K_(ATP)) channel opener,diazoxide,in different concentrations,against the myocardial injury in isolated rabbit hearts caused by ischemia/reperfusion.?Methods The experiment was performed in isolated rabbit hearts perfused on Langendorff apparatus.40 rabbit hearts were randomly divided into five groups.The hearts were first arrested by cold cardioplegia for 45 min before warm K-H solution was reperfused for 20 min.Diazoxide of different concentrations,1,30,50 and 200 μmol/L,was perfused for 15 min before the heart stopped beating.The hemodynamic indexes were determined in the course of reperfusion.The ultrastructural and biochemical studies on the myocardium were made be the end of the experiment.?Results In contrast to the findings in the control group,the recovery of myocardial contractility and heart rate was earlier in the test groups,the myocardial MDA level and the release amount of albumen were lower,the activities of creatin kinase(CK) and lactate dehydrogenase(LDH) were much lower,and also,the level of myocardial ATP was higher(P0.05 or 0.01).?Conclusion The drug preconditioning with diazoxide and the hyperpolarized arrest induced by diazoxide(200 μmol/L) may offer myocardial protective effect against ischemia/reperfusion injury.