Abstract: OBJECTIVE: To investigate the effect of Sini decoction on rats with myocardial fibrosis induced by banding the abdominal aorta, and explore the mechanism underlying its actions on angiotensin Ⅱ(Ang Ⅱ), transforming growth factor-β_1(TGF-β_1)and connective tissue growth factor(CTGF).METHODS: Forty-eight male Sprague-Dawley rats were randomly divided into sham operation, model, Captopril, and Sini decoction groups. The models were established by the partial banding of the abdominal aorta according to Doering's method.Eight weeks later, heart weight indexes were calculated; hemodynamic changes of the hearts were tested; changes in myocardial tissue morphology were observed by Masson staining; and myocardial collagen volume fraction was calculated. Enzyme-linked immunosorbent assay was used to measure the concentration of Ang Ⅱ in serum. The expression of TGF-β_1 and CTGF were determined by immunohistochemistry and Western blotting.RESULTS: Compared with the sham operation group, the heart weight index, collagen volume fraction of the myocardium, serum levels of Ang Ⅱ,and the expression of myocardial TGF-β_1 and CTGF in the model group were significantly increased(P < 0.05). Compared with the model group, the heart weight index, collagen volume fraction of the myocardium, serum levels of Ang Ⅱ, and the expression of myocardial TGF-β_1 and CTGF in all treatment groups were significantly reduced(P < 0.05).CONCLUSION: Sini decoction reduced AngⅡ level and inhibited the expression of myocardial TGF-β_1 and CTGF, which may explain the mechanism of its protective effect on myocardium with fibrosis.

Key words: Myocardial fibrosis, Angiotensin Ⅱ, Transforming growth factor beta1, Connective tissue growth factor, Sini decoction