Glomerular Cell Replication and Cell Loss through Apoptosis in Experimental Diabetes mellitus

Abstract

Aim: To evaluate changes in the glomerular cell balance between replication and apoptosis in experimental diabetes mellitus (DM) in relation to morphometric data. Methods: Adult Sprague-Dowley rats with streptozotocin-induced DM and controls of the same age and strain were sacrificed 4 and 8 weeks and 6 months after disease onset. Cell replication was demonstrated with MIB-5, and apoptosis with the terminal uridine nick end labeling technique. Glomerular size and glomerular cell population were estimated morphologically. Results: Diabetic and control rats showed irrelevant MIB-5 positivity at all time points. Glomerular apoptosis was minimal in rats with 4 and 8 weeks of DM and in controls. Rats with 6 months of DM showed significantly higher glomerular apoptosis values than controls (2.49 ± 0.25 vs. 0.65 ± 0.16%; p < 0.001). The mean cell count per glomerular profile was significantly lower in these diabetic rats (64.02 ± 1.93 vs. 78.27 ± 0.99; p < 0.001), a change that correlated with that in apoptosis. The glomerular cell density was further decreased in diabetic rats because of the diabetic increase in mean glomerular volume (1.598 vs. 0.927 10⁶ µm). Conclusions: Apoptosis is associated with loss of glomerular cells in rats with long-term, streptozotocin-induced DM and – to a considerably lower degree – in controls of the same age and strain. These changes could be relevant to glomerulosclerosis associated with long-term, streptozotocin-induced DM.