Glomerular alterations in experimental diabetes of the rat.

To detect structural glomerular alterations in the early stages of diabetes mellitus glomeruli from young streptozotocin diabetic rats were studied by light microscopy with morphometric methods 2, 8, 12 and 24 weeks after induction of diabetes. It was found that there is a marked increase in the percentage mesangial surface as compared with the control animals already two weeks after induction of diabetes. The relative mesangial surface fraction was greater in the diabetic animals than in the controls at all test times. It was also demonstrated that the endothelial cell count was reduced in the diabetic animals in the first few weeks of the study. High-grade glycosuria and proteinuria were likewise observed in the diabetic animals. Hence the mesangium appears to be one of the glomerular structures which shows the first changes in the initial stages of diabetes mellitus. Possibly the most likely cause of the changes based on the present study is the diabetic metabolic state (or the insulin deficiency).