Effect of ethanol extract of Rhodiola rosea on the early nephropathy in type 2 diabetic rats

This study aimed to investigate the therapeutical effects of Rhodiola rosea extract on rats with type 2 diabetic nephropathy (DN). The rat type 2 DN model was established by high fat and high calorie feeding and intravenous injection of streptozocin (STZ). Wistar rats were randomly divided into normal group, control group, low dose Rhodiola rosea group, high dose Rhodiola rosea group and Captopril group. Oral glucose tolerance test (OGTT) was performed to determine the impairment of glucose tolerance in the established animal model. A series of parameters including fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), creatinine clearance rate (Ccr), 24-h urinary albumin (UA), the ratio of kidney mass/body weight (renal index) and glomerular area were examined after 8 weeks. Moreover, the expression of transforming growth factor (TGF)-beta 1 in renal tissues was detected by using immunohistochemisty. At the end of the eighth week, FBG, TC, TG, Ccr, 24-h urinary albumin, the ratio of kidney mass/body weight and glomerular area were significantly reduced in Rhodiola rosea extract treatment groups as compared with those in control group. TGF-beta 1 expression in renal tissues of Rhodiola rosea extract treatment groups was also significantly decreased as compared with that of control group. These results indicate that Rhodiola rosea extract may have a protective effect on early nephropathy in diabetic rats, which might be related to the decrease of the renal expression of TGF-beta 1.