The expression of AngII and metalloproteinases and its inhibitors in the myocardial of diabetic rats and their effect

Objective To investigate the expression of AngⅡ,transforming growth factor (TGF)β1,matrix metalloproteinases (MMP)-1 and tissue inhibitors of metalloproteinases (TIMP)-1 in diabetes mellitus (DM) rats and their relation to myocardial interstitial remodification.Methods 20 male SD rats were randomly divided into normal control group and DM group 〔induced by streptozotocin (STZ)〕,10 in each group.Ten weeks later,all rats were killed to measure expression levels of type Ⅰ,Ⅲ collagen,TGFβ1 protein,MMP-1 and TIMP-1 protein by immunohistochemistry method and detect the mRNA expressions of MMP-1 and TIMP-1 by RT-PCR.Results The cardiac index and the left ventriclular index were significantly higher in DM group than those in normal group(P0.05).The expression of AngⅡ,type Ⅰ,Ⅲ collagen,TGF-β1 protein,TIMP-1 protein and mRNA were also significantly higher in DM group than those in normal group,while the expression of MMP-1 protein and mRNA were significantly lower in DM group (P0.05).Conclusions The activation of renin-angiotensin system (RAS) in diabetic rat will increase the expression of AngⅡ,which may directly or indirectly effect the expression of TGFβ1 and MMPs ,all of this will result in the myocardial interstitial remodification of diabetic rat.