Abstract: Objective： To explore mechanism is dynamic expression and internal relations of c-kit gene and microRNA-21 in rat ventricular remodeling .Methods :SD rats(n=140) were randomly divided into normal control group(n=15) and heart failure model group(n=125). Heart failure model : 4 mg/kg intraperitoneal injection of adriamycin. To detect the cardiac function of rats in eight weeks, proving the heart failure. Then harvesting the rat heart, frozen section, using immunohistochemistry and immunofluorescence color to detect the expression changes of microRNA-21 and c-kit in myocardial tissue.Results: The emergence of the pathological changes of cardiac muscle cells after myocardial infarction in the heart failure groups and the control group didn’t appear the myocardial infarction and heart failure. Immunohistochemistry and immunofluorescence show that microRNA-21 positive cells in normal and heart failure myocardium mainly express in vascular endothelium,a few myocardial cells and stem cells, and endocardial expressing quantity fell more than epicardial; c-kit positive cells tend to cluster together, mainly gather in the epicardial and its nearby, and the expressing quantity decrease significantly after heart failure.A small number of cells exsit microRNA-21 and c-kit common expression in both groups(P < 0.05). Conclusion: The decreased expression of c-kit and microRNA-21 is highly relevant in rats heart failure and left ventricular remodeling.

Key words: c-kit, MicroRNA-21, Myocardial Stem cells, Immunohistochemistry, immunofluorescence, Ventricular remodeling, Rat heart