Abstract: Objective To investigate the effects of Tangshen Formula on liver oxidative stress in diabetic rats, and their mechanisms thereof．Methods Rat model of type 2 diabetes mellitus and nonalcoholic fatty liver disease was established by intraperitoneally injecting small dose of chain urea with cephalosporins (STZ) and feeding high fat fodder．The model rats were randomly divided into control group, model group, Tangshen Formula group and metformin group．The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), cholesterol (CHO), low density lipoprotein-cholesterol(LDL-C), and superoxide dismutase (SOD), catalase(CAT), vitamin E(VE), nitric oxide (NO) and nitric oxide synthase (NOS) in liver were compared between four groups. Changes of pathological morphology were observed under light microscopy. Results There were significantly decrease in serum levels of ALT, AST, TG, CHO, LDL-C in Tangshen Formula group and metformin group compared with those of model group. There were significantly higher levels of SOD, CAT and VE, and lower levels of NO and NOS of liver homogenate in Tangshen Formula group than those of model group. There were higher levels of SOD and CAT, and lower levels of NO and NOS in liver homogenate in metformin group than those of model group. HE staining showed that liver fatty degeneration was significantly reduced in metformin group and Tangshen Formula group compared with that of model group. Conclusion The fatty liver in type 2 diabetic rats is significantly improved by Tangshen Formula treatment, which is probably associated with the regulation of the response level to oxidative stress in liver．

Key words: Tangshen Formula, Type 2 diabetes, Liver injury, Oxidative stress