Effect of diazoxide postconditioning on cardiac function and mitochondri-al cardiolipin in isolated rat heart / 中国病理生理杂志

ABSTRACT

AIM: To investigate the effect of diazoxide (D) postconditioning on Cardiac function and mito-chondrial cardiolipin in isolated rat heart and to explore the protective effect of ATP sensitive potassium channel on diazo-xide postconditioning myocardium.METHODS: The myocardial ischemia/reperfusion injury model in isolated rat hearts was established by Langendorff apparatus.The isolated rat hearts were randomized into 4 groups ( n=8) control group ( control) , myocardial ischemia/reperfusion injury group ( I/R) , diazoxide postconditioning group ( I/R+D) , 5-hydroxy decanoic acid (5-HD) plus diazoxide postconditioning group (I/R+5-HD+D).The hearts in each group were started with 20 min perfusion for equilibration.The hearts in control group perfused for 70 min;The hearts in I/R group was global ischemia for 40 min after ischemia reperfusion at 4℃ST.Thomas cardioplegia, then reperfusion for 30 min;The hearts in I/R+D group were treated with diazoxide (50μmol/L) in K-H perfusion for 5 min after global ischemia for 40 min, then reperfusion for 25 min;The hearts in I/R+5-HD+D group were treated with 5-HD (100μmol/L) in K-H perfusion for 5 min before diazoxide postconditioning, then reperfusion for 20 min.The heart rate, coronary outflow volume, heart func-tion, myocardial enzymes and myocardial mitochondrial cardiolipin at the end of perfusion in each group were determined. RESULTS:Compared with control group and I/R+D group, the heart rate, the concentration of heart phospholipid and the coronary outflow volume were reduced, the heart function was significantly impaired the contents of myocardial enzymes were increased in I/R group.However, no significant difference between I/R group and I/R+5-HD+D group was ob-served.CONCLUSION:The diazoxide postconditioning protects the myocardium by increasing mitochondrial cardiolipin content, reducing the release of myocardial enzymes, improving heart function and reducing myocardial reperfusion injury. The myocardial protective effect of diazoxide is completely blocked by 5-hydroxy decanoic acid.