Preconditioning with mitochondrial ATP-sensitive potassium channel opener,diazoxide,protects the myocardial mitochondial functions after ischemic injury in rats

Objective To investigate the effect of preconditioning with mitochondrial ATP-sensitive potassium channel opener on the mitochondrial functions.Methods Thirty SD rats were used.Isoproterenol was used to induce myocardial ischemic injury in 20 rats,ten of which were pretreated with diazoxide.Rhodamine123(Rh123)was used as fluorescent prober to measure mitochondrial membrane potential.The activities of mitochondrial Na+-K+-ATPase and Ca2+-ATPase were detected.The mitochondrial respiratory parameters were recorded with a Clark electrode.The effect of diazoxide on mitochondrial membrane potential and mitochondrial respiration was investigated.Results Compared with the controls,the levels of state 3(ST3),respiratory control rate(RCR),mitochondrial membrane potential content and the activities of mitochondrial ATPase were decreased in the rats that received isoproterenol,while diazoxide pretreatment alleviated the changes of ST3,RCR,mitochondrial membrane potential and the activities of mitochondrial ATPase.Conclusion Preconditioning with diazoxide enhances the activities of mitochondrial ATPase and protects the myocardial mitochondrial function after isoproterenol induced myocardial ischemic injury.