Protein expression of matrix metalloproteinase 9 in renal tissues of diabetic rats and renoprotective effect of valsartan

Objective To investigate the protein expression of matrix metalloproteinase 9(MMP 9) in the renal tissue of diabetic rats and the renoprotective effect of valsartan.Methods The following groups of rats were involved in the study:normal control rats, streptozotocin induced diabetic rats and diabetic rats treated with valsartan(50 mg·kg-1·d-1). MMP 9 protein expression and activity were measured by zymography and immunohistological staining at 4,8 weeks of experiment.In addition,the relation between MMP 9 and collagen Ⅳ,laminin in the renal tissue of diabetic rats was examined. Result By immunohistological staining,positive expression of MMP 9 protein was mainly observed in normal glomerular cells,renal tubular cells,which became weaker in the diabetic rats as compared with normal control rats(P 0 01).The activity of MMP 9 reduced significantly in diabetic rats as well,which was negatively correlated with collagen Ⅳ(r=-0 801,P 0 001)and LN(r=-0 811,P 0 001).Valsartan increased remarkably the expression and activity of MMP 9 in the renal tissue compared to diabetic rats(P 0 05). Conclusion MMP 9 may play a role in the formation of ECM in diabetic nephropathy,while valsartan may possess an effect on the protection of the diabetic nephropathy partly through increasing the expression and activity of MMP 9 in the renal tissue.