Effects Of Simvastatin On Cardiac Function And Angiogenesis In Rabbits After Myocardial Infarction

Objectives: 1?. Evaluating the effects of simvastatin on cardiac function in rabbits after experimental myocardial infarction. 2. Evaluating the effects of simvastatin on angiogenesis in rabbit MI model. Methods: 1. Experimental objective: Chinese female rabbits, 2.0 to 2.5 kg in body weight. 2. Experimental groups: All animals are divided into three groups.Ⅰsham-operated group ,Ⅱcontrol group and ⅢSimvastatin-treated group.Ⅰsham-operated group only open thoracic cavity and pericardial cavity, Ⅱgroup and Ⅲgroup' animal were MI model. The model was created by liquid nitrogen directly freeze myocardium. Simvastatin (5mg/kg per day) was administered daily in Ⅲgroup, the others was given placebo. Adjust the daily dose of drug or placebo after the body weights were measured every week. After eight weeks of treatment the animals will be sacrificed. 3.Detective parameters: ①Serum cholesterol levels were measured at baseline and 8 week respectively after operation;②The count of microvessels near the margin of the infarcted myocardium were evaluated by immunohistochemical exams 8 weeks later;③Left ventricular end-diastolic diameter (LVDD) and left ventricular end-systolic diameter (LVSD )were measured by echocardiography at 1 week, 2 week, 4 week, 8 week respectively after operation, and left ventricular ejection fraction (LVEF) will be counted . Results:1. The serum cholesterol levels in Simvastatin-treated group were significantly decreased after treated, but control group and sham-operated group had no changes. As compared with sham-operated group and control group, Simvastatin-treated group was significantly decreased at eighth week after operation. 2.The microvessel count of Simvastatin-treated group was significantly increased than control group (140.29±5.28: 41.14±3.98 , p<0.001). 3.The cardiac function in sham-operated group had no changes during the study period ,the left ventricular ejection fraction was 79.07%±1.25%,78.30%±1.06%,78.67%±0.93%,78.63%±1.04%; at 1 week, 2 week, 4 week, 8 week after operation . At first week, control group and Simvastatin-treated group have similar cardiac function .As compared with sham-operated group , their cardiac function decreased significant. At second week , the cardiac function of Simvastatin-treated group was better than that of control group(61.96%±0.89%:60.13%±1.39%, P﹥0.05). At fourth week , there is a significant difference between control group and Simvastatin-treated group (47.95%±1.62%:55.78%±1.87%,P﹤0.01).At eighth week,the difference become small ,but the cardiac function of Simvastatin-treated group was better than control group (45.24%±2.65%:41.37%±1.65%,P﹤0.01) . Conclusions:1 Short-term statins therapy can retard the progression of cardiac dysfunction in rabbit MI model. 2. Simvastatin therapy can induce effective angiogenesis near the margin of the infarcted myocardium in rabbit MI model.