Suppression of transforming growth factor-β1 gene expression by danggui buxue tang, a traditional Chinese herbal preparation, in retarding the progress of renal damage in streptozotocin-induced diabetic rats

Danggui buxue tang (DBT), a preparation containing Angelica sinensis (danggui) and Astragalus membranaceus (huangqi) at a ratio of 1:5, is used widely in China for stimulating red blood cell production and enhancing cardiovascular function. The present study was undertaken to characterize the effects of this preparation on diabetic nephropathy using streptozotocin-diabetic rats as a model. Streptozotocin-dependent alterations in renal weight/body weight ratio, urinary albumin and beta(2)-microglobulin concentrations, urinary albumin excretion rate, and creatinine clearance were ameliorated after eight weeks of treatment with either DBT or the angiotensin-converting enzyme inhibitor, benazepril. DBT, but not benazepril, partially attenuated the increases in blood glucose, triglycerides and cholesterol in STZ-diabetic rats. Additionally, the increased expression of transforming growth factor-beta(1) mRNA in the renal cortex due to streptozotocin-induced diabetes was modestly attenuated by these treatments. However, eight weeks of treatment with DBT failed to modify the concentration of angiotensin II in plasma or kidney, indicating that the ability of the preparation to retard the progression of kidney disease was not attributable to inhibition of the renin-angiotensin system. We propose that DBT alleviates renal alterations in diabetes and slows the progression of diabetic nephropathy by suppressing transforming growth factor-beta(1) mRNA expression. The preparation may therefore be useful as an adjuvant therapy for controlling diabetes and its complications.