Effects of Jiangya Xiaoke prescription on TGF-β1 in diabetic nephropathy rats with hypertension and its mechanisms.

OBJECTIVE To observe the effects of Jiangya Xiaoke prescription on transforming growth factor-β1 (TGF-β1) in diabetic nephropathy (DN) with hypertension rats and to investigate its mechanisms. METHODS DN with hypertension models were made by 4 weeks high-salt diet with high sugar and fat for male Wistar rats, and intraperitoneal injection of streptozotocin (STZ). The model rats were randomly divided into three groups: untreated model group (n = 15); metformin group (n = 15), orally given metformin; Prescription group (n = 15), orally administrated JXR, for 8 weeks respectively. Blood pressure was measured before modeling and after treatment of 2, 4, 8 weeks. Fasting blood glucose (FBG), total triglyceride (TG) and total cholesterol (TC) and urine albumin excretion (UAE) of rats were observed and recorded. Renal histomorphology with PAS staining was observed by the light microscope. TGF-β1 in kidney was detected by immunohistochemical assay and TGF-β1 mRNA in renal cortex was detected by RT-PCR. RESULTS The base blood pressure of rats has no significant difference before modeling (P > 0.05). After 4 weeks of treatment, compared with model group, blood pressure in metformin group decreased (P < 0.01), blood pressure in Jiangya Xiaoke prescription group was slightly lower (P < 0.05). When 8 weeks, the rebound of blood pressure in metformin group is appropriate with the model, the blood pressure of Jiangya Xiaoke prescription reduced significantly (P < 0.01). Compared with model group, FBG, UAE and TG in Jiangya Xiaoke prescription group and metformin group significantly decreased (P < 0.01), TC levels also decreased (P < 0.05). The level of TGF-β1 in Jiangya Xiaoke prescription group and the metformin group decreased (P < 0.01), and level of TGF-β1 in Jiangya Xiaoke prescription group was lower significantly than that in metformin group (P < 0.05). The mRNA expression of TGF-β1 in Jiangya Xiaoke prescription group and the metformin group was significantly lower than model group (P < 0.01). Pathological changes were ameliorated in Jiangya Xiaoke prescription and metformin group compared with model group. CONCLUSION Jiangya Xiaoke prescription can regulate blood pressure and improve renal functional morphology through down-regulation of TGF-β1 and its mRNA expression in DN rats with hypertension. We initially proved that the inhibition effect of TGF-β1 in Jiangya Xiaoke prescription is better than metformin, and Jiangya Xiaoke prescription can lower blood pressure to normal levels with a better step-down smoothly and a long-term efficacy.