Effects of Losartan on Expression of Transforming Growth Factor-β_1 and Extracellalar Matrix Components in the Glomeruli of Diabetic Rats

Objective: To investigate the influence of losartan on expression of transforming growth factor-β 1 and extracellular matrix components in the glomeruli of diabetes rats. Methods: 36 rats were randomized into three groups : normal control group (group C, n=12) , streptozotocin diabetic group (group D, n=12) and the group of diabetic rats treated with losartan(group DL, n=12, 10mg·kg -1·d -1 of losartan injected into left-lower part of abdominal cavity since the 2 nd day of streptozotocin injection). Blood glucose、urinary albumin、 plasma Angiotensin Ⅱ concentration as well as profile of kidney hypertrophy were observed after 4、 8 weeks of treatment , while TGF-β 1 , fibronection and collagen Ⅳ expression were measured by immunohistochemistry. Results:Urinary albumin excretion and kidney hypertrophy index of losartan treated group were significantly lower than those of diabetic untreated group (P0.01 ). There was a significant increase in protein expression of TGF-β 1, fibronection and collagen Ⅳ in diabetic rats (P0.01 ) . The expression of TGF-β 1 (P0.01 ) protein as well as the protein expression of fibronection and collagen Ⅳin the losartan group were much lower than that in the diabetic group (P0.05 ). Conclusion: The results suggest that losartan has some renal protective effect on diabetes in rats , partly by down-regulating TGF-β 1 expression and reducing deposition of glomerular ECM .