Enalapril attenuates increased gene expression of extracellular matrix components in diabetic rats

This study was designed to assess whether the glomerular expression of mRNA for extracellular matrix (ECM) components including alpha 1 (I), alpha 1 (III), and alpha 1 (IV) collagen chains, laminin B1 and B2 chains, metalloproteinases (MMP), and tissue inhibitor of metalloproteinases (TIMP) is affected by enalapril in 12- and 24-wk-old rat after streptozotocin injection. Animals were divided into three groups; untreated diabetic rats, enalapril-treated diabetic rats, and control rats. Enalapril treatment was continued for 24 wk. Enalapril reduced both creatinine clearance (P < 0.01) and urinary protein excretion (P < 0.01) in diabetic rats. In diabetic rats, mRNA levels for alpha 1 (IV) collagen chain, laminin B1 and B2 chains, and alpha 1(I) and alpha 1(III) collagen chains increased significantly at 24 wk compared with those in controls [alpha 1(IV): 3.8-fold (P < 0.01); laminin B1: 6.2-fold (P < 0.01); laminin B2:5.4-fold (P < 0.01), alpha 1(i): 4.8-fold (P < 0.01) and alpha 1(III): 3.8-fold (P < 0.01)]. At 24 wk, mRNA levels for MMP-1 and MMP-3 fell to 40% (P < 0.01) and 20% (P < 0.01), respectively, in the glomeruli of diabetic rats compared with levels in controls. In contrast, mRNA levels for TIMP-1 and TIMP-2 increased significantly at 24 wk after streptozotocin injection (TIMP-1: 8.0-fold (P < 0.01) and TIMP-2: 6.4-fold (P < 0.01)).(ABSTRACT TRUNCATED AT 250 WORDS)