Effects of Rat Myocardial Infarction Models by Different Occlusion Time Course of LAD On Infarction Size And Heart Function

Objective To study the feasibility of establishment of myocardial infarction models induced by different occlusion time course of left anterior descending(LAD) in rats,provide a considerably reliable model for the study of repair or rebuild rat myocardial infarction by stem cells transplantation.Methods Myocardial infarction was induced by LAD occlusion in male Wistar rats.There is 60 male Wistar rats were randomly divided into six groups: acute LAD occlusion(15,30,45 or 60 min) with reperfusion or permanent LAD occlusion group.1day,1week,2weeks or 4weeks after different LAD ligation treatment,Pathological morphology,IS and mortality were be detected and analyzed.And 1month After LAD occlusion,We used multipurpose polygraph to measure heart rate(HR),left ventricular systolic pressure(LVSP),left ventricular end-diastolic pressure(LVEDP),±dp/dtmax,artery systolic pressure(ASP),artery diastolic pressure(ADP).Results The myocardial necrosis or infarction was formed by LAD occlusion for at least 30 minutes.Almost the same infarct area had formed in rats among occlusion(45 or 60 min) with reperfusion groups,or permanent occlusion group.However,when arterial blood flow was restored(occlusion with reperfusion),the scattered bleeding and cell damage in rat myocardial infarction area occurred.After permanent LAD occlusion or occlusion reperfusion,nearly 25% rats died of ventricular fibrillation within 4 hours,and most of them died within the first 30 minutes.The heart sections from rats of one day,one week,or one month after LAD occlusion showed the typical acute myocardial infarction pathological morphology.Compared to the LAD occlusion(15 or 30 min) with reperfusion group,ASP,LVSP and±dp/dtmax of the LAD occlusion(45 or 60 min) with reperfusion or permanent LAD occlusion group were decreased,LVEDP increased.Conclusion Our findings suggest that rat acute myocardial infarction model is the most stable by LAD occlusion(at least 45 minutes) with reperfusion and this model is suitable for the research on stem cells transplantation.