Perfusion of rat kidneys with polycation protamine, resulted in pathologic alterations of glomeruls very similar to those observed in minimal change nephrotic syndrome in human. In the experimental model, colloidal iron staining of kidney tissue sections was analyzed quantitatively by image analyzer, the mean thickness foot processes and foot processes making up the volume fraction of glomerular capillary by stereology, with the observetion of other glomerular ultrastructure. The studies showed that there was a significant decrease in glomerular polyanions of kidneys perfused with protamine as compared with that of the control group (P<0.01). The glomerular alterations included swelling and fusion of foot processes, narrowing or loss of filtration slits. Electron-dense particles by binding of protamine to polyanions were seen primarily in the lamina rara externa of glomerular basement membrane, but also along the lamina rara interna and on the foot process surface, which showed the distribution feature of glomerular filter. These results suggests that the ultrastructure alterations of glomeruli may result from the neutralization of polyanions by perfusion with protamine.
