Abstract: Objective　To investigate the protective effects of carnosine (CAR) on diabetic nephropathy(DN) in rats and its effects on oxidative stress and NF-κB signaling pathway.　Methods　Sixty SD male rats of 8-week-old, except the normal group (n=12), were given high fat and sugar diet, and intraperitoneal injection of STZ to establish diabetes rats model. Three days after the injection of STZ, the rats that conform to pre-determined criterion were randomly divided into a diabetic nephropathy group and a carnosine (100, 300, 900 mg/kg) group. The carnosine groups were intragastrically administered with 100, 300, and 900 mg/kg carnosine once a day. After 8 weeks of carnosine administration, fasting blood glucose (FBG), serum creatinine (Scr), blood ureanitrogen (BUN), and 24-hour micro albumin (mAlb) were measured. Morphological changes of rat kidney were observed by PAS staining. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the content of malondialdehyde (MDA), glutathione (GSH) in the nephropathy were detected by respective commercial kits. Renal tissue phosphate NF-κB P65 protein expression were detected by immunochemistry and Western blot.　Results　The carnosine can effectively alleviate the pathological damage of kidney tissue. Compared with the diabetic nephropathy group, carnosine could decrease the levels of 24h urine protein, FBG, Scr and BUN, with a dose-effect manner (P<0.05). Carnosine also could increase the contents of SOD, MDA, GSH, GSH-Px and decrease phosphate NF-κB P65, and the content of MDA in kindey. Conclusions　Carnosine had a protective effect on rats of DN model, and its protective mechanism may relate to the inhibition of oxidative stress and NF-κB signaling pathway.

Key words: Diabetic nephropathy, 　Carnosine, 　Oxidative stress, 　NF-κB, 　Rats model