[Polydatin ameliorates myocardial fibrosis in rats by up-regulating SIRT3 and SDF-1].

Objective To investigate the effects and the possible mechanisms of polydatin on the myocardial fibrosis and cytokines of myocardium induced by adriamycin. Methods Twenty male SD rats was divided into four groups, 5 rats in every group. Control group (only fed with conventional diet), adriamycin group (treated with intraperitoneal injection of 2.5 mg/kg adriamycin for twice a week), polydatin treatment group (treated with intraperitoneal injection of 50 mg/kg polydatin for once a day) and nicotinamide treatment group (treated with intraperitoneal injection of 500 mg/kg SIRT3 inhibitor nicotinamide for twice a week). The effects of polydatin on adriamycin induced myocardial fibrosis and collagen expression in myocardium were evaluated by immunohistochemistry. The content of hydroxyproline (HYP) in myocardium was detected by enzyme labeling method. Spectrofluorometry was used to determine the level of superoxide dismutase (SOD) activity, glutathione (GSH) and malonaldehyde (MDA) level. ELISA was used to detect the content of tumor necrosis factor α(TNF-α), interleukin 1(IL-1)and IL-10. The levels of SIRT1, SIRT3, transforming growth factor-β (TGF-β) and stromal cell-derived factor-1(SDF-1) were examined by real-time quantitative PCR and Western blotting.Results Treatment with adriamycin promoted the myocardial fibrosis, reduced the level of IL-10, increased the level of TNF-α, IL-1 in myocardial tissue. The mRNA and protein levels of SIRT3 and SDF-1 was inhibited by adriamycin, whereas the expression of TGF-β was promoted. The results showed that polydatin inhibited the fibrosis of myocardium induced by adriamycin, decreased the level of HYP, collagen III and MDA , whereas the level of SOD and GSH was increased. Treatment with nicotinamide attenuated the inhibitory effects of polydatin on the fibrosis of myocardium, inhibited the expression of SIRT3 and SDF-1, promoted the expression of TGF-β. Conclusion Polydatin upregulates the expression of SIRT3 to increase the ability of anti-fibrosis and reduce the level of oxidative stress induced by adriamycin, inhibits the relase of cytokines.