Effect of postconditioning on expression of heat shock protein 70 in hyperlipemia rats with myocardial ischemia reperfusion

Objective To study effect of postcondition on expression of Heat shock protein 70 in rats with myocardial ischemia reperfusion.Methods In anesthetized open-chest rats,the left anterior descending(LAD) coronary artery was occluded for 40 min and reperfused for 4 h.36 rats were randomly divided into three groups: Control(n=12): no intervention at R;Ischemic postconditioning(IP)(n=12): after LAD occlusion,three cycles of 10s R followed by 10s LAD reocclusion were applied during the first minute of R;Sham(n=12): the surgical procedure was identical to other groups,but the LAD ligature was not ligated.The expression of HSP70 was detected by immunohistochemistry.The presence of apoptotic myocytes was detected by the method of terminal Deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL).Meanwhile,the serum creatine kinase activity was measured.Results Zero creatine kinase activity in IP group was lower than that in control group(P0.05).The amount of HSP70 in IP group was significant higher than that in control group and sham operation group(P0.05).There was no significant apoptosis found after the reperfusion in the sham-operation group,and the apoptotic rate in the ischemic postconditioning group was remarkably lower than that in the ischemic reperfusion group.Conclusions IP can reduce myocardial ischemia reperfusion injury significantly.The myocardial protection of postconditioning may be realized by increasing the expression of HSP70 and decreased myocardial apoptosis.