Expression of transformation growth factor-β type IIreceptor in injured vessels in diabetic rats and the modulation of losartan

Objective To investigate the expression of transformation growth factor-β type Ⅱreceptor (TGF-βⅡR) in injured vessels in diabetic rats and the modulation of losartan. Methods Sixteen Wistar rats were served with stretozotocin (STZ) 60 mg/kg each rat by intraperitoneal injection. After that, they were randomly divided into diabetic + angioplasty group (diabetic group) and diabetic+angioplasty +losartan therapy group (losartan group), 8 rats in each group. Another 16 rats were randomly divided into normal control group and angioplasty control group. All rats were treated with balloon denudation from thoracic to left iliac aorta. Losartan was administrated by gavage with a dose of 20 mg·kg -1·d -1 during the period of 7 days before operation to 14 days after operation in losartan group. Thoracic aortae were collected to detect:(1) Vascular smooth muscle cells (VSMCs) TGF-βⅡR,Ⅰα(Ⅳ)procollagen mRNA expression with RT-PCR and Northern blot; (2) aortae wall AngⅡconcentration; (3) the protein expression of VSMCs TGF-βⅡR, Ⅰα(Ⅳ)procollagen with immunohistochemistry. Results (1) AngⅡconcentration, TGF-βⅡR and Ⅰα(Ⅳ)procollagen mRNA as well as protein expression were significantly higher in diabetes group than that in angioplasty control group,which was markedly higher in angioplasty control group than that in normal control group (P0.01). (2)Administration of losartan could reduce AngⅡconcentration, it also could suppress TGF-βⅡR, Ⅰα(Ⅳ)procollagen mRNA and protein expression by 60%, 57%, 62%,46% respectively.Conclusion These findings indicated that there was an interaction between TGF-βⅡR and the pathogenesis of restenosis in injured vessels in diabetic group. Losartan can inhibit the expression of TGF-βⅡR in vascular wall.