Abstract: Objective: To investigate the effect of the extract of Schisandra chinensis on the matrix metalloproteinases(MMPs) system in kidney tissue of the diabetic rats,and to explore its protective effect on the kidney tissue from the matrix degradation perspective. Methods: STZ was used to establish rat models of diabetes mellitus. A total of 45 diabetic rats were randomly divided into model group,extract of Schisandra chinensis group and Benazepril group,and there were 15 rats in each group.Another 15 rats were selected and used as normal control group.12 weeks after administration,the routine blood and urine biochemical indexes,the histological changes,blood glucose (BG), blood urea nitrogen(BUN),serum creatinine(Scr),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterin(LDL-C),total cholesterol(T-CHO),and triglyceride(TG) levels, excretion rates of albuminuria and proteinuria of the rats in various groups were detected; the expression amounts of fibronectin (FN),type Ⅳ collagen (Col Ⅳ),and matrix metalloproteinase inhibitor metalloproteinase-2 (TIMP-2) in kidney tissue of the rats were detected by immunohistochemical method; the activity of matrix metalloproteinase-2 (MMP-2) was detected by zymography. Results: Compared with model group,the glomeruli matrix accumulation of the rats in extract of Schisandra chinensis group was significantly improved,the excretion rate of albuminuria,LDL-C level and serum MDA level were decreased(P<0.05),the activities of CAT(P<0.01)and SOD(P<0.05)in kidney tissue were increased,and the level of MDA in kidney tissue was decreased(P<0.05). The immunohistochemistry results showed that compared with model group,the expression amounts of FN,Col Ⅳ,and TIMP-2 in kidney tissue of the rats in extract of Schisandra chinensis group were significantly decreased.The zymography results showed that compared with model group,the activity of MMP-2 in kidney tissue of the rats in extract of Schisandra chinensis group was significantly increased(P<0.05). Conclusion: Extract of Schisandra chinensis has protective effect on the kidney tissue of the diabetic rats induced by STZ,and the mechanism may be related to the inhibition of oxidative stress and the improvement of MMP-2 activity as well as the inhibition of TIMP-2 expression which could improve the matrix degradation.

Key words: extract of Schisandra chinensis, matrix metalloproteinase, matrix metalloproteinase inhibitor, diabetic nephropathy