Influence of ischemic postconditioning on Caspase-3 activity in myocardium of rats with hyperlipidemia after ischemia/reperfusion

Objective: To study influence of ischemic postconditioning on Caspase(cysteine aspartase)-3 activity in myocardium of rats with hyperlipidemia after ischemia/reperfusion(I/R).Methods:A total of 48 SD rats with hyperlipidemia were randomly divided into sham operation group(n=16),I/R group(n=16,ligated to cause ischemia for 40 min,then reperfused for 240 min) and ischemic postconditioning group(n=16,after 40 min ischemia,reperfused for 10s and ischemia for 10s for three cycles,then reperfused for 240 min).After reperfusion,blood sample was taken from right carotid artery to measure activity of creatine kinase(CK),Caspase-3 activity and apoptotic extent of myocardial cells.These indicators were compared and analyzed among three groups.Results:After reperfusion,① CK activity in ischemic postconditioning group and I/R group were significantly higher than that of sham operation group [(745.26±62.18) U/L vs.(926.38±76.49) U/L vs.(237.67±21.82) U/L],and that of ischemic postconditioning group was significantly lower than that of I/R group(P0.05 all);② There was no obvious apoptosis(5%) in sham operation group,apoptosis rate of myocardial cells in ischemic postconditioning group was significantly lower than that of I/R group [(11.7±2.6)% vs.(20.8±3.4)%,P0.05];③ Caspase-3 activity in ischemic myocardial tissues in ischemic postconditioning group was significantly lower than that of I/R group [(545.79±98.25) μmol PNA/mg vs.(739.83±113.57) μmol PNA/mg,P0.01].Conclusion: Ischemic postconditioning can relieve ischemia/reperfusion injury in rats with hyperlipidemia;its myocardial protection may be related with decrease of Caspase-3.