Abstract: AIM: To study the effects of noninvasive delayed limb ischemic preconditioning (NDLIP) on myocardium ischemia-reperfusion injury in diabetic rats.METHODS: The acute diabetic rat models were induced by injecting streptozotocin(STZ) through vena caudalis.The diabetic rats were randomly divided into ischemia-reperfusion (IR) group, cardiac ischemic preconditioning (CIP) group and NDLIP group.Rats in NDLIP group subjected to NDLIP left hind limb for 3 days, and at the fourth day, all rats were subjected to myocardial ischemia reperfusion injury.Rats in CIP group were myocardial ischemic preconditioning before ischemia.Blood pressure and electrocardiogram were monitored continuously.The effects of myocardial electrophysiology function, myocardial infarction size and myocardial enzyme were observed in the diabetic rats with NDLIP after myocardium ischemia-reperfusion injury , and the superoxide dismutase(SOD) , the activities of glutathion peroxidase(GSH-Px) , the content of malonaldehyde in rats muscular tissues were detected.RESULTS: The levels of blood glucose were increased and the body weights were decreased in diabetic model rats(P<0.01).Compared with I R group, the elevation extent of ST segment in NDLIP and CIP group were degraded, the emergence time of ventricular premature contraction and ventricular tachycardia were delayed and the duration of both was shortened, and the incidence of ventricular arrhythmia was decreased (P<0.05) , the myocardial infarct size was reduced (P<0.01) , the releases of cadiocyte lactate dehydrogenase (LDH) , creatine kinase (CK ) , and creatine kinase isozyme were decreased (P<0.05, P<0.01) , the activities of SOD and GSH-Px in rats muscular tissues were increased (P<0.01) and the content of MDA was decreased in CIP and NDLIP groups(P<0.05, P<0.01).CONCLUSION: NDLIP can relieve cadiocyte damage induced by I R injury in the diabetic rats and the leakage of cardiac muscle enzyme is decreased , and the physiologic function of heart is improved, the cardiac protective effects of NDLIP group and CIP group are considerable.The effects are associated with the regulation of the equilibrium between oxidation and antioxidation system in myocardium.

Key words: noninvasive, delayed, limb, ischemic preconditioning, diabetes, ischemia-reperfusion, myocardial enzyme, oxidation and antioxidation system