Ultrastructural Changes in Glomerular Anionic Sites in Puromycin Aminonucleoside Nephropathy

An ultrastructural study was done on puromycin aminonucleoside (PAN) nephropathy which was induced in a group of Sprague-Dawley rats by a single intraperitoneally injected dose. To study the ultrastructural alteration of glomerular anionic sites renal tissue was stained with polyethyleneimine (PEI) as a cationic probe. The PEI method seemed to selectively stain heparan sulfate proteoglycan in the basement membrane and has been widely used to evaluate the changes of the basement membrane in human diseases as well as in experimental work. The experimental rats developed proteinuria three days after the PAN injection. Electron microscopic studies of glomeruli showed the loss of epithelial foot processes, formation of cytoplasmic vacuoles, microvillous formation, and increased numbers of lysosomes in the cytoplasm of podocytes. The anionic sites on the basement membrane with foot process fusion were mostly indistinguishable from those seen in control rats, but focal areas of loss or disarray of anionic sites were noted. The anionic sites were not seen on the basement membrane where the overlying epithelium was detached. The results suggest that proteinuria in PAN nephrosis may be primarily due to a glomerular epithelial lesion, leading to focal disarray of anionic sites or focal defects in the epithelial covering of the basement membrane. The loss of anionic sites in the basement membrane may result partially from the foot process fusion, but mostly from the epithelial detachment.

Morphological Changes in Glomerular Epithelial Cells and Basement Membranes in Puromycin Aminonucleoside Induced Nephropathy / 대한신장학회잡지

Puromycin aminonucleoside (PAN) nephropathy was induced in a group of Sprague-Dawley rat by a single dose of intraperitoneal injection to study an ultrastructural alteration of glomerular anionic sites by stain with polyethyleneimine (PEI) as a cationic probe and to examine whether proliferation of podocytes occur by immunohistochemical stain for proliferating cell nuclear antigen (PCNA). The experimental rats developed proteinuria three days after PAN injection. Electron microscopic studies of glomeruli showed the loss of epithelial foot processes, formation of cytoplasmic vacuoles, microvillous formation and increased numbers of lyso- somes in the cytoplasm of podocytes. PEI method seems to selectively stain heparan sulfate proteogly-can in basement membrane and has been widely used to evaluate the changes of basement membrane in human disease as well as in experimental work. The anionic sites on the basement membrane with foot process fusion were mostly indistinguishable from those seen in control rats, but focal areas of loss or disarray of anionic sites were noted. The anionic sites were not seen on the basement membrane where the overlying epithelium was detached. It is strongly suggested that proteinuria in PAN nephrosis may be primarily due to a glomerular epithelial lesion, leading to focal disarray of anionic sites or focal defects in the epithelial covering of the basement membrane. The loss of anionic s'ites in the basement mernbrane may be resulted partially from the foot process fusion and mostly from the epithelial detachment. The increased numbers of PCNA positive cells after the injection of PAN is suggestive of possibility of podocytic proliferation or regeneration.