Zhen-wu-tang, a blended traditional Chinese herbal medicine, ameliorates proteinuria and renal damage of streptozotocin-induced diabetic nephropathy in rats

Abstract Ethnopharmacological relevance Zhen-wu-tang (ZWT) is a blended traditional Chinese medicine specifically used for various kidney diseases. Aim of the study The present study is to evaluate the effects of ZWT on diabetic nephropathy and investigate the potential anti-diabetic mechanisms. Materials and methods Streptozotocin (STZ)-induced diabetic rats were orally administrated ZWT (80,320 mg/kg b.w.) once a day, for a period of 12 weeks. Body weight, urinary volume, urine protein and blood biochemical parameters were measured every 3 weeks. At the end of the observation period, kidneys were isolated for histology, angiotensin II content determination, real time PCR and Western blot analyses. Results ZWT (320 mg/kg b.w.) prevented body weight loss, reduced polyurea, urinary protein excretion, serum creatinine and blood urea nitrogen, although it did not alter the hyperglycemia. It ameliorated glomerular hypertrophy and expansion of the mesangial area, swell and effacement of foot process. It also suppressed the increased expression of angiotensin II, nephrin and podocin. Conclusions Data from this study suggest that ZWT possess a protective effect on renal damage of STZ-induced diabetic nephropathy in rats, by suppressing hyperactivity of renal renin–angiotensin system that turns in to modulate renal nephrin and podocin expressions, thereby protecting podocyte from injury.