[Effect of Chinese herbal medicine with Supplement Qi and Activating Blood Circulation on tubular reabsorption function of diabetic nephropathy rats].

OBJECTIVE: To investigate the effect of Chinese herbal medicine with Supplement Qi and Activating Blood Circulation (huangqi and danshen) on urinary protein, kidney function and tubular reabsorption of diabetic nephropathy rats.

METHODS: SD rats were randomly divided into a nondiabetic control group (normal group) and three groups in which diabetes were induced by a single intraperitoneal injection of freshly prepared streptozotocin( STZ,55 mg/kg body weight). Then the diabetes rats were randomly assigned to three groups: diabetic model group, Supplement Qi and Activating Blood Circulation traditional Chinese medicine group (huangqi and danshen group) and Gliquidone group (as a reference hypoglycemic drug). Each group was treated with corresponding drugs for 6 weeks. At the end of the study, the rats from each group were injected with FITC-labeled BSA through tail vein. The 24 h urinary protein excretion were measured and blood was collected for measuring plasma glucose levels, serum creatinine (Cr), blood urea nitrogen (BUN), triglyceride (TG) and total cholesterol (T-CHO). Renal tissue was used to measure the level of LPO,SOD,GSH-Px and AGEs and Paraffin-embedded sections were stained with HE, PAS and immunohistochemistry.

RESULTS: The plasma glucose, the 24 h urinary protein excretion, the levels of serum Cr, BUN, TG and T-CHO in STZ-induced diabetic rats were higher than those of nondiabetic rats. Diabetic rats showed significantly increase in LPO and AGEs (P < 0.01) and decrease in antioxidant enzyme activity (both GSH-Px and SOD) (P < 0.05) as compared with non-diabetic control rats. Treatment with the Supplement Qi and Activating Blood Circulation traditional Chinese medicine for 6 weeks in diabetic rats significantly reduced the 24 h urinary protein excretion compared with model control (P < 0.01), and markedly decreased the levels of serum Cr,BUN,TG and T-CHO as compared with those of diabetic rat (P < 0.05). The levels of LPO and AGEs were decreased and the activity of GSH-Px was increased by Supplement Qi and Activating Blood Circulation treatment. The kidney proximal tubule lesions were improved and the reabsorption of FITC-BSA in tubular was increased in diabetic rats treated by huangqi and danshen, and the expression of megalin in proximal tubular was enhanced as compared with diabetic rats.

CONCLUSION: Diabetic nephropathy rats treated with traditional Chinese medicine therapeutic principles "Supplement Qi and Activating Blood Circulation" can reduce the 24 h urinary protein excretion and improve the function of tubular reabsorption. These protect effects may be in correlation with enhancement the renal tissue activity of antioxidant and up-regulation the expression of megalin in renal tubular epithelial cells in diabetic rats.