Structural Alterations of the Glomerular Wall and Vessels in Early Stages of Diabetes Mellitus

OBJECTIVE The capillary changes at the initial stage of diabetes may show an angioarchitecture clearly different from those of later stages and/or very severe glomerular change. However, the onset of alterations in the early phases is unclear. This study attempts to determine the structural alterations of the glomerular wall and vessels in the early stage of diabetes. MATERIAL AND METHODS Twenty-five adult rats were used in this study. They were divided into two groups: the first group of five was used as a control. The second group of 20 (the experimental group) was injected intraperitoneally by a single dose of streptozotocin to induce hyperglycemia. Rats were sacrificed after ten days, two months, and four months. Five rats at two months of age with hyperglycemia were treated with insulin for eight weeks. Renal tissues were prepared by routine technique for light and transmission electron microscopic evaluation. RESULTS By light microscopy after ten days of induced hyperglycemia, there were no structural modifications detected either in renal glomerular fine vessels or in the glomerular basement membrane of the glomerular capillaries. After two months, there was a moderate glomerular enlargement and dilatation of glomerular capillaries, afferent, and efferent arterioles. After four months, glomerular basement membrane thickening was the only structural alteration observed. Recovery of the glomerular alterations was observed after two months of treatment with insulin. CONCLUSION In early stages of diabetes mellitus in rats, there was an increase in the diameter of glomerular vessels. In later stages of the disease, the reverse was seen, but insulin treatment had a positive role in reversing these changes in the study subjects.