A Study of Myocardial Ischemia Model Induced by Left Coronary Artery Ligation in Rats

Objective: Coronary artery was ligated to study the characteristics of myocardial ischemia in rats. Methods: The left anterior descending artery was ligated to establish the rat model of acute myocardial ischemia. All animals were divided into normal control group, sham operation group and model group. 1, 2 and 4 weeks after modeling, ECG (II lead) was recorded, the weight of whole heart and left ventricle were recorded and organ indexes were calculated; myocardial infarct size was determined by TTC; CK, CK-MB, LDH, AST contents of serum were detected; cardiac function was determined by left ventricular intubation via carotid artery and left ventricular was taken to perform pathological observation. Results: 1 week after modeling, compared with the sham operation group, the ECG and heart function index of rats model had significant change, but the myocardial enzymes did not change significantly; 4 weeks after modeling, the ECG and cardiac function of animal models had a recovery trend, but the myocardial enzymes, including CK, CK-MB, LDH, AST, were significantly increased; 1 week after modeling, the left ventricular indexes of model rats were increased; the infarct size was about 30%, myocardial cell necrosis and granulation tissue hyperplasia could be observed in infarction area; with the modeling time extended, from 2 to 4 weeks, the left ventricular and heart indexes of model group were significantly increased; the infarct size was relatively constant, left ventricular became thickly, and fibrous or granulation tissue was significantly proliferated in infarction area under microscope. Conclusion: The indexes of myocardial ischemia induced by coronary artery ligation in rats are different at different time points. The results suggest that the time point should be selected to observe the anti-myocardial ischemia effect of the subjects from different aspects. These authors contributed equally to this work and should be considered co-first authors. Corresponding author.