Alteration in the distribution of type IV collagen in glomerular basal laminae in diabetic rats as revealed by immunocytochemistry and morphometrical approach.

The glomerular basal laminae of normoglycaemic and long-term streptozotocin-induced hyperglycaemic rats was studied by morphometrical and immunocytochemical approaches. Using the orthogonal intercept method, we have confirmed that in long-term diabetes, the thickness of the glomerular basal laminae increases significantly. Applying the high resolution protein A-gold immunocytochemical technique, type IV collagen was localized in the glomerular basal laminae. In tissues from normoglycaemic animals the labelling was present over the central lamina densa. However, the labelling obtained over the thickened glomerular basal laminae of the hyperglycaemic animals was restricted to the subendothelial site of the lamina. Thus major alteration in the distribution of type IV collagen occurs during the development of diabetic microangiopathy in hyperglycaemic animals.