ラットアミノヌクレオシド腎症の病理学的研究 ： 糸球体病変の経時的推移とフィブロネクチンの糸球体内局在について

Abstract

The aim of this study is to describe the morphologic characteristics of the early changes of focal sclerotic lesions in aminonucleoside (AN) nephrosis. AN nephrosis was induced by repeated injection of puromycin aminonucleoside in WKA rats. Sequential changes in glomerular lesions were observed by light and electron microscopy. In the early stages, a number of glomeruli were found to adhere to Bowman's capsule without focal sclerotic lesion and/or hyalinosis. Electron microscopy showed degeneration of the podocyte, such as by foot process fusion, microvilli formation, vacuolation or lysosome in its cytoplasma. Moreover, detachment of the podocyte and some denuding of the glomerular basement membrane were noted. These features seem to be initiating events for capsular adhesion, leading to deposition of hyaline or proteinaceous material and desquamation of endothelial cells in the capillary lumen. Immuno-electron microscopy was used to study the localization of fibronectin in the controls and in the glomeruli with AN nephrosis. In the controls, fibronectin was mainly restricted to the mesangial matrix, especially in the area surrounding the mesangial cell process and at the interface between endothelial and mesangial cells. In the glomeruli with focal sclerotic lesion, fibronectin increased proportionately with expansion of the mesangial matrix. Deposition of fibronectin was also found subendothelially along the glomerular basement membrane and in the region of capsular adhesion. The results suggest a possible role of fibronectin in the pathogenesis of focal sclerotic lesion.