Myocardial protection by Salvia miltiorrhiza Injection in streptozotocin-induced diabetic rats through attenuation of expression of thrombospondin-1 and transforming growth factor-ß1.

OBJECTIVES: To investigate the myocardially protective effects of Salvia miltiorrhiza injection in streptozotocin-induced diabetic rats and the possible mechanisms involved. METHODS: Adult male Sprague-Dawley rats were randomized into three groups (n = 10 per group): diabetes, no treatment (Sm-); diabetes, S. miltiorrhiza injection (Sm+); control (no diabetes; saline treatment). After model induction and 4 weeks' treatment, heart function of five rats from each group was tested by Langendorff isolated in vivo heart perfusion. In the remaining rats, pathological changes of the myocardium were observed by haematoxylin and eosin staining, and protein levels of thrombospondin-1 (TSP-1) and transforming growth factor-ß1 (TGF-ß1) were assessed by immunohistochemistry. RESULTS: Left ventricular systolic end pressure and left ventricular developed pressure were significantly improved in the Sm+ group compared with the Sm- group. Pathological changes were ameliorated through significantly reduced TSP-1 and TGF-ß1 protein levels. CONCLUSIONS: S. miltiorrhiza injection may improve the heart function of diabetic rats and protect against cardiomyopathy by downregulating TSP-1 and TGF-ß1 in myocardial tissue.