Abstract: Objective To observe the effects of different doses of salvianolic acid B on nuclear transcription factor NFE2-related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1) in kidney of diabetic nephropathy (DN) model rats. Methods Forty SPF male Sprague-Dawley rats were randomly divided into control group (not modeled), model group, low dose of salvianolic acid B (10 mg/kg) and high dose of salvianolic acid B (20 mg/kg) groups. Rats of DN model were prepared by intraperitoneal injection of streptozotocin (STZ, 40 mg / kg) combined with high-sugar and high-fat diet. After modeling,salvianolic acid B treatment group was given the corresponding dose of medicine, and the control group and model group were given equal volume of olive oil intragastrically for 6 weeks. At the end of the treatment, samples of 24-h urine were collected from each group of rats for the detection of 24-h urine protein content. The blood glucose, serum creatinine, total cholesterol and triglyceride levels were measured by eyeball blood. The expressions of Nrf-2 and HO-1 protein and mRNA in renal tissues were detected by reverse transcriptase PCR (RT-PCR) and Western blot assay. PAS staining was used to observe the degree of renal tissue lesion in each group. Results Compared with the control group, the 24-h urine protein,blood glucose, serum creatinine, total cholesterol and triglyceride levels were significantly increased, and the expression levels of Nrf-2, HO-1 protein and mRNA in renal tissues were also significantly increased in the model group (P＜0.05).The pathological changes in renal tissue were significantly increased by PAS staining. Compared with the model group, 24-h urine protein, blood glucose, serum creatinine, total cholesterol and triglyceride levels were significantly decreased in the low and high doses of salvianolic acid B groups. The contents of cholesterol and triglyceride were significantly decreased, and the expression levels of Nrf-2 and HO-1 protein and mRNA in renal tissues were significantly increased (P＜0.05). Thepathological changes in renal tissue were significantly decreased by PAS staining. And the effect of salvianolic acid B was dose dependent. Conclusion A certain dose of salvianolic acid B can up-regulate the expression of Nrf-2 and HO-1 in renal tissues and resist oxidative stress.

Key words: diabetic nephropathies, heme oxygenase-1, rats, Sprague-Dawley, salvianolic acid B, biochemical index, Nrf-2