The Effects Of Limb Ischemic Perconditioning On Myocardial No-peflow In Hyperlipidemia Golden Hamsters

Background and Objecive: Ischemic heart disease is a common andfrequently-occurring disease with high mortality rate. Nowadays, the main way to treatthe disease is reperfusion. But the myocardial reperfusion can cause myocardialreperfusion injury, and no-reflow phenomenon(NR) is one of damage phenomena needto solve urgently. After myocardial ischemia occurred, recanalization and blood flowrestore, but the ischemia area does not receive adequate blood perfusion, thisphenomenon is called no-reflow phenomenon. Limb ischemia perconditioning iscurrently one of the strong endogenous protective mechanisms for ischemic myocardial,and its operation is simple, easily being accepted by patients and their families.Ourformer research had verified that limb ischemic perconditioning could reducemyocardial no-reflow phenomenon in normal rats, but myocardial no-reflowphenomenon ofter occurs in abnormal human body in clinic, such as hyperlipidemia,hypertension, hyperglycemia and so on. In view of this, we chose hyperlipidemiagolden hamsters model to observe the effects of limb ischemic perconditioning on themyocardial no-reflow phenomenon.We aimd to establishe a hyperlipidemia animal model to investigate the effects of limbischemic preconditioning on myocardial no-reflow in hyperlipidemia golden hamstersand to make a preliminary study on the mechanisms of it.Methods: Sixty golden hamsters were randomly divided into two groups respectivelytreated with ordinary diet and high-fat diet. After2weeks, contents of TC and TG in serum were measured to determine that hyperlipidemia animal model was successfully,set up. Then each group was randomly divided into three groups: cardiacsham-operation(Sham)、 cardiac ischemia-reperfusion(I-R)、 cardiac I-R add limbischemia PerC. The I-R model was created with1-h coronary ligation followed by1.5-hreperfusion with an open-chest surgical approach. The PerC was created with theocclusion of blood flow to one hindlimb by tourniquet, and it was delivered with threecycles of3-min coronary ligation followed by3-min reperfusion. Each protocol of PerCwas delivered at the end of index ischemia and completed just before reperfusionstarted. After1.5-h reperfusion, blood was collected and myocardial tissue was stained.ECG detection, myocardial TTC and HE staining,MDA, LDH and CK-MB level ofserum were detected to observe changes in myocardial injury. Descent rate of STsegment in ECG and thioflavine S staining were detected to observe changes ofmyocardial no-reflow; ET-1, eNOS，ICAM-1and E-selectin contents of ischemia tissuewere detected to observe fuctions and adhesiveness of endothelial cells.Results: After PerC intervention was performed, the infarct area and NR area weresignificantly reduced than I-R group(ordinary P<0.01, hyperlipidemia P<0.05respectively). Activity of Lactate dehydrogenase,malondialdehyde and creatine kinaseisozyme in the PerC group were lower than those in the I-R group(ordinary P<0.01,hyperlipidemia P<0.05respectively). Compared with I-R group, the myocardial cellinjury was weaker in PerC group (ordinary P<0.01, hyperlipidemia P<0.05respectively). The level of ET-1,ICAM-1and E-selectin decreased in the PerC groupcompared with I-R group(ordinary P<0.01, hyperlipidemia P<0.05respectively),whilethe level of eNOS increased (ordinary P<0.01, hyperlipidemia P<0.05respectively).Conclusion: This study showed that:1) high fat diet feeding the golden hamsters could successfully establish hyperlipidemia model;2) limb PerC could reducemyocardial no-reflow and infarction size, the mechanisms of which may be related toinhibited cell adhesion and improved endothelial cell function.