Abstract: Objective　To observe the changes of lipid droplet in cardiomyocytes and cardiac function of hyperlipidemia rats, and the expression changes of heart type fatty acid binding protein (H-FABP). Methods　High fat diet SD male rats was established hyperlipidemia rat model. After feeding for 4 weeks, 8 weeks and 12 weeks, the cardiac function of the rats was detected and the heart was removed. Frozen sections were stained with oil red O, and the distribution of lipid droplets in the myocardium was observed under light microscope. The changes of lipid droplets in myocardium were observed by transmission electron microscope. The expression of H-FABP in cardiomyocytes and myocardium was detected by immunohistochemistry, immunofluorescence and Western blotting.　Results　Compared with the normal diet rats, the serum triglyceride and total cholesterol increased significantly in the high-fat diet rats, the most obvious was in the 12 week, accompanied by a significant reduction in ejection fraction, increasing of lipid droplets in myocardial cells. The number of H-FABP in myocardium and myocardium increased significantly at the 8th week and the 12th week.　Conclusions　The myocardium of hyperlipidemia rats occurs fatty degeneration. With the increasing concentration of blood lipid, the fatty degeneration and the heart function decrease, which may be related to the increasing of H-FABP expression and the increasing of fatty acid oxidation in cardiac myocytes.

Key words: H-FABP, 　Hyperlipidemia, 　Myocardium fatty degeneration, 　Immunohistochemistry,  , Immunofluorescence, 　Western blotting, 　Rat heart function