[Changes in anionic sites on glomerular basement membrane following mesangiolysis--observation in incipient anti-rat Thy1 nephritis].

To clarify whether heparan sulfate proteoglycans (HSPG) on glomerular basement membrane (GBM) are produced by mesangial cell in vivo, the number of anionic sites (AS) on lamina rara externa of GBM and the changes in urinary albumin excretion rate (UAE) were observed on mesangiolysis in rats induced by monoclonal anti-rat Thy1 antibody. Mesangiolysis was remarkable at day 3 after the administration of anti-rat Thy1 antibody, whereas GBM as well as epithelial cell remained well preserved, and detached endothelial cell was observed. The number of AS on GBM was significantly (p < 0.001) decreased in anti-rat Thy1 antibody treated rats (18.6 +/- 0.4/1000nm), when compared with that of normal control rats (22.8 +/- 0.4/1000nm). Furthermore, UAE was markedly (p < 0.05) increased at day 3 (1692.6 +/- 627.5 micrograms/24h) compared with the value before (188.2 +/- 30.6 micrograms/24h) administration of anti-rat Thy1 antibody. From these results, it can be concluded that some part of AS on GBM may be produced by the mesangial cell.