[Effect of Danzhi Jiangtang Capsule on Myocardial Fibrosis in Diabetic Rats].

ABSTRACT

OBJECTIVE: To investigate the effect of Danzhi Jiangtang Capsule on myocardial fibrosis in diabetic rats with fluctuated blood glucose and the possible mechanisms implicated. METHODS: Following induction of diabetes with intraperitoneal injection of streptozotocin (STZ), rats were administered with insulin or glucose at different time during a day to induce blood glucose fluctuation. After treatment with Danzhi Jiangtang Capsule for six weeks, rats were sacrificed and the hearts were collected for the determination of cardiac mass index. Cardiac levels of angiotensin II (Ang II), type I and type III collagens and transforming growth factor-ß1 (TGF-ß1) were assayed by ELISA. Levels of Smad3 phosphorylation and protein expression of matrix metalloproteinase-2 ( MMP-2) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) were determined by Western blot analysis. Total antioxidant capacity and malondialdehyde (MDA) content in cardiac tissues were measured colorimetrically. RESULTS: Treatment with Danzhi Jiangtang Capsule for six weeks significantly reduced cardiac mass index and cardiac levels of type I and type III collagens (P < 0.05 or P < 0.01). Levels of Ang II, TGF-ß1 and Smad3 phosphorylation in cardiac tissues were also decreased markedly (P < 0.05 or P < 0.01). Supplementation with Danzhi Jiangtang Capsule resulted in an evident up-regulation of MMP-2 protein and down-regulation of TIMP-2 protein expression in cardiac tissues (P < 0.05 or P < 0.01). In addition, Danzhi Jiangtang Capsule significantly enhanced total antioxidant capacity in diabetic rats, while cardiac content of MDA was decreased markedly( P < 0.05 or P < 0.01). CONCLUSION: Danzhi Jiangtang Capsule significantly ameliorated myocardial fibrosis in diabetic rats with fluctuated blood glucose, which might be derived from enhancement of antioxidant capacity, suppression of RAS and TGF-ß1/Smad3 signaling pathway and regulation of MMP-2/TIMP-2 protein expression.