Kinetic study of glomerular cells of diabetic rats in relation to the development of irreversible glomerular sclerosis

In order to clarify the cellular kinetics involved in progression of diabetic glomerulosclerosis, the epithelial cells of spontaneously diabetic $\text{WBN}\text{Kob}$ rats were investigated by labeling with the DNA precursor bromodeoxyuridine, which was histochemically stained using monoclonal antibody. The labeling index (number of labeled cells/number of cells counted) of glomeruli was constantly low (approximately 0.15%) and no significant variation could be demonstrated in control rats of the Wistar strain. In both control and diabetic rats, podocytes showed no evidence of mitosis. In contrast to capillary podocytes, the Bowman epithelial cells of diabetic rats showed increased labeling, often surrounding sclerotic capillaries. These observations suggest a critical role of Bowman's epithelial cells in the development of irreversibly sclerotic glomeruli in diabetic nephropathy.