Abstract: Objective: To study the relationship between myocardial remodeling and endoplasmic reticulum stress and autophagy in rats with ischemic cardiomyopathy. Methods: Thirty-six male SD rats were divided into normal control group, sham-operated group and ischemic cardiomyopathy group (n=12). Echocardiography was performed before operation in three groups. Rats in sham-operated group closed their thoracic cavity without ligation of coronary artery after thoracotomy. The rats in ischemic cardiomyopathy group were closed their thoracic cavity after ligating of coronary artery for 20 minutes and recovered reperfusion. After operation for 4 weeks, rats in three groups were killed after taking echocardiography. The myocardial tissues were taken for HE staining and Masson staining to observe the pathological changes of myocardium and the expressions of glucose-regulated protein 78 (GRP78), microtubule-associated protein 1 light chain 3- I (LC3-I), microtubule-associated protein 1 light chain 3- II (LC3-II), Bcl-2 interacting protein (Beclin-I) and the ratio of LC3-II/LC3-I were detected by Western blot. Results: Compared with normal group and sham-operated group, ischemic cardiomyopathy rats had significant differences in echocardiography and myocardial pathology; the myocardial array was disordered, myocardial fibrosis was increased, mitochondrial vacuolation was serious. Mean while, the expressions of GRP78, LC3-I, LC3-II, Beclin-I and LC3-II/LC3-I ratio had significant changes. Conclusion: Autophagy and endoplasmic reticulum stress may play important roles in myocardial remodeling in rats with ischemic cardiomyopathy.

Key words: ischemic cardiomyopathy, myocardial remodeling, endoplasmic reticulum stress, autophagy, rat