[Altered glomerular mRNA expression of basement membrane components and type I collagen in diabetic rats treated with or without insulin therapy].

Glomerular basement membrane (GBM) thickening has been reported to be a characteristic change of diabetic nephropathy. Previous studies of GBM in animal models of diabetes indicated that there are no consensus in the alteration of synthesis of GBM component. The aim of this study was to determine whether the glomerular mRNA levels encoding type I and type IV collagen. B1 laminin, and heparan sulfate proteoglycan (HSPG) are altered in streptozotocin diabetic rats with or without insulin therapy. Glomerular mRNA levels for type I and type IV collagen, laminin B1, were significantly increased, but that for HSPG were marked decreased in 4 week diabetic rats compared with age-matched control rats. Insulin therapy has normalized these abnormally regulated gene expressions. Renal morphology shows no significant changes between 4 weeks diabetic rats and age-matched control rats. These results indicate that abnormal gene expressions of BM components and type I collagen might play an important role in the initiation of glomerular changes in diabetes.