Effects of Houttuynia Cordata Thumb on Expression of BMP-7 and TGF-β1 in the Renal Tissues of Diabetic Rats

Institute of Integrative Traditional Chinese & Western Medicine, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430030, China 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 β2-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-β1, BMP-7 and collagenⅠin the renal tissues was observed with the immunohistochemical method and by the semi-quantitative assay. Results: The overgrowth of glomerulus, the excretion of β2-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 collagenⅠ 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 collagenⅠand with the increase of the expression of BMP-7 in the renal tissues.