Effects of melatonin on myocardial ischemia-reperfusion injury in rats

Objective:To assess the effects of melatonin on myocardial ischemia reperfusion injury in rats.Methods: Two groups of rats, group A (n=12) received cardioplegia with melatonin. Group B(n=12) as control. Isolated rat hearts were subjected to preperfusion for 30 min, ischemia for 120 min and reperfusion for 30 min using a modified Langendorff Neely model with modified Krebs Henseleit buffer at 37℃. The hemodynamic parameters, myocardial enzyme (CPK, LDH), myocardial superoxide dismutase (SOD), myocardial lipid peroxide (LPO) and myocardial ultrastructure were measured before ischemia and during reperfusion.Results: Recovery of cardial function and myocardial ultrastructure in group A was significantly better than that in group B. In group A, CPK, LDH and LPO were significantly lower (P 0.01 ) and SOD was significantly higher than that in Group B (P 0.01 ). Conclusion: Out results suggest that melatonin supplement in cardioplegia alleviate the reperfusion mediated myocardial injury.