Protective effects of Croton hookeri on streptozotocin-induced diabetic nephropathy

In this study, the protective effects of Croton hookeri (CH) extract on renal injury were investigated in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced by a single injection of STZ (45 mg/kg) to Sprague-Dawley rats. After 5 days, CH extract (200 mg/kg) was administered daily by oral gavage for 2 weeks. Administration of CH extracts significantly reduced blood glucose levels in STZ-induced diabetic rats. STZ-induced changes in total cholesterol, LDL, HDL, ALT, AST, BUN, and serum creatinine levels were significantly restored by treatment with CH extract. Abnormal levels of SOD, catalase, glutathione, and oxidized GSH (GSSG) in STZ-treated rats were also significantly recovered by CH extract treatment. CH extract markedly reduced the expression of collagen-1, fibronectin, and α-SMA in the kidney of STZ-induced diabetic rats. In particular, oxidative DNA damages, MDA, TGF-β, IL-1β, and IL-6 levels were significantly reduced in STZ-treated rats following treatment with CH extract, whereas IL-10 showed opposite trend. STZ-induced SIRT1, SIRT3 downregulation and cloudin-1 upregulation in the kidney were dramatically recovered by CH extract treatment. Our data suggest that CH extract protects against diabetic-induced nephropathy by inhibiting oxidative stress and inflammation. Therefore, it has potential as a food supplement to alleviate renal dysfunction caused by diabetes-induced nephropathy.