Remnant kidney pathology after five-sixth nephrectomy in rat. II. Electron microscopy study.

In Wistar male rats, hypertension was induced by 5/6 nephrectomy (5/6N). Electron microscopy revealed an increase in the number of epithelial cells on the Bowman's capsule during the early stages (4 weeks). After 8 and 12 weeks, frequent adhesion was observed between the glomerular tuft and Bowman's capsule. The abnormal podocytes showed nuclear irregularities and distortions. Characteristic foot process fusion formed cytoplasmic plates. There was a considerable increase in mesangial matrix and cells. No immune deposits or breaks in the glomerular basement membrane were observed. In the endothelial cells, the fenestration disappeared in sclerosed glomeruli. Some capillary loops were obliterated by fibrin, macrophages and foam cells. These findings combined with our previous light microscopy and immunofluorescent observations suggest a non-immunogenic glomerular sclerosis.