Objective： To explore the effects of Houttuynia Cordata Thumb （HCT 鱼腥草 Yu Xing Cao） on expression of transforming growth factor-β1 （TGF-β1） and bone morphogenetic protein-7 （BMP-7） in the renal tissues of diabetic rats. Methods： The diabetic rats induced by intravenous injection of streptozotocin（STZ） were randomly divided into a model group, a HCT group and a lotensin group, with normal rats designated as the controls. 8 weeks later, the ratio of kidney weight to body weight, the glomerular area, the excretion of β 2-microglobin （β2-MG） in 24-hr urine, the albumin excretion in 24-hr urine, and creatinine clearance rate （CCR） were investigated. The expression of TGF- β 1, BMP-7 and collagen I in the renal tissues was observed with the immunohistochemical method and by the semi-quantitative assay. Results： The overgrowth of glomerulus, the excretion of β 2-MG in 24-hr urine, the albumin excretion rate in 24-hr urine and CCR in the HCT group significantly reduced （P〈0.05）, and the expression of TGF-β1 and collagen I significantly decreased （P〈0.05）, but BMP-7 significantly increased （P〈0.05） in the HCT group as compared with those in the model group, with no significant difference as compared with the lotensin group （P〉0.05）. Conclusion： HCT has a protective effect on the renal tissues in diabetic rats, which is probably correlated with the decrease of the expression of TGF-β1 and collagen I and with the increase of the expression of BMP-7 in the renal tissues.
