Experimentally induced ultrastructural changes in epithelial cells of isolated glomeruli
Nörgaard, J.O.
Laboratory Investigation; A Journal of Technical Methods and Pathology 41(3): 224-236
1979
ISSN/ISBN: 0023-6837 PMID: 470341 Document Number: 149649
The ultrastructure and the colloidal Fe staining characteristics were studied in the visceral epithelial cells of isolated and in vitro incubated glomeruli in which alterations were induced by adding different substances to the culture medium. Treatment with polycations, in particular protamine sulfate, induced rapid alterations, whereas incubation with the aminonucleoside of puromycin, vinblastine sulfate or cytochalasin B did not alter the appearance of the epithelial cells. The polycation-induced lesions were characterized by rapid swelling of the cells, the adhesion of cell membranes, and the disappearance of interprocessal spaces below the epithelial cell bodies. The mean distance between the centers of the filtration slits was unchanged after 10 min of incubation with protamine, but incubation for more than 1 h resulted in an increase in the slit to slit interdistance, indicating the induction of retraction of the foot processes by the protamine. The staining pattern of protamine-treated glomeruli with colloidal Fe appeared the same as in controls. The protamine-induced epithelial alterations could be almost completely reversed by subsequent incubation with the polyanionic heparin. Cell swelling and development of adhesions between adjacent cell membranes are probably the major factors in the development of the polycation-induced epithelial lesions.