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Nephroprotective Effect of Danzhi Jiangtang Capsule on Diabetic Rats and its Mechanism

??OBJECTIVE To investigate the nephroprotective effect of danzhi jiangtang capsule(DJC) on diabetic rats induced by streptozotocin(STZ) and elucidate its mechanism. METHODS Model of diabetic rats were established by combination of high-fat diet-fed and low-dose STZ injection in SD rats. The successful models were chosen and randomly divided into model group, low-dose and high-dose of DJC(600, 2 000 mg??kg^-1, ig)groups, each consisting of 8 rats. Control and model groups were administered equal volume of distilled water. After 8 weeks of treatment, the rats were killed and serum was separated to detect blood lipid, renal function and oxidative stress. The kidneys were weighed, and the renal indexes were calculated. Renal tissue specimens were fixed for HE and PAS staining; the expressions of JAK2, STAT3, p-JAK2, p-STAT3 in the kidneys were observed by Western blot; the renal inflammatory factors TNF-??, IL-6 and MCP-1 were detected by ELISA. RESULTS Fasting blood glucose (FBG), blood lipid, renal index, oxidative stress of model group were significantly increased, renal function was reduced, and the morphology of renal tissue changed significantly. The renal inflammatory cytokine TNF-??, IL-6 and MCP-1 and the expressions of p-JAK2, p-STAT3 increased significantly in diabetes mellitus rats. After 8 weeks of treatment, blood lipid and oxidative stress in DJC groups were decreased, but there was no obvious difference in FBG between DJC groups and model group, the renal function and the pathological changes of renal tissue were improved obviously. The expressions of inflammatory cytokine(TNF-??, IL-6 and MCP-1), p-JAK2 and p-STAT3 in renal cortex were significantly down-regulated. CONCLUSION The nephroprotective effect of DJC is based on its antioxidant effect and anti-inflammatory effect via suppression of JAK2/STAT3 signal transduction.