Tochimaru H
Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan.
Hokkaido Igaku Zasshi. 1991 Nov;66(6):829-40.
In order to evaluate the pathogenesis of proteinuria and the charge of immune deposits in lupus nephritis, anionic sites of periodate-lysin-paraformaldehyde (PLP) fixed renal tissue (5 patients with renal pelvic tumor as normal control and 17 patients with lupus nephritis), were stained with the critical electrolyte concentration method. Cuprolinic blue (CB) was used as a cationic probe. Ultra-structural study and semi-quantitative analysis were done. In the normal glomerular basement membrane (GBM), the CB stainable anionic sites appeared as filamentous structure with several short lateral branches. On the basis of electron microscopic observation of isolated proteoglycan, it is suggested that the central filaments are the protein core and the branches are the glycosaminoglycans of proteoglycan molecules. These filamentous anionic sites were located mainly in the laminae larae and lie close to each other forming a mesh-like network pattern. The semi-quantitative analysis of the normal GBM revealed that the number of anionic sites in the lamina rara externa (LRE) was 22.9 +/- 1.9-23.7 +/- 1.4/1000 nm GBM and in the lamina rara interna (LRI) 14.0 +/- 1.6-15.1 +/- 1.5/1000 nm GBM. These findings suggest that the anionic sites composed of heparan sulphate proteoglycan occupy large area of the laminae larae and prevent permeation of anionic molecules. In non-proteinuric 5 patients with class II lupus nephritis, the number of anionic sites of the GBM (LRE; 21.3 +/- 2.0-22.3 +/- 1.8/1000 nm GBM, LRI; 13.5 +/- 2.0-14.2 +/- 2.0/1000 nm GBM) showed no significant difference from that of the normal GBM. In contrast, the GBM of proteinuric patients with class IV (6 patients, LRE; 14.8 +/- 2.7-19.3 +/- 1.8/aooo nm GBM, LRI; 5.8 +/- 1.9-11.3 +/- 2.4/1000 nm GBM) and (V) (6 patients, LRE; 13.0 +/- 2.4-17.9 +/- 2.8/1000 nm GBM, LRI; 12.0 +/- 1.9-13.0 +/- 2.5/1000 nm GBM) exhibited loss of the anionic sites in association with the localization of the immune deposits (ID). From these findings, it is concluded that in severe and active lupus nephritis the failure of charge barrier of the GBM is responsible for the proteinuria. The ID observed in the patients with lupus nephritis were not stained with CB. This finding suggests that net charge of the ID could be cationic and that cationic immune complex and/or antibody could involve in the pathogenesis of lupus nephritis.
为了评估狼疮性肾炎中蛋白尿的发病机制及免疫沉积物的电荷情况，采用临界电解质浓度法对高碘酸盐 - 赖氨酸 - 多聚甲醛（PLP）固定的肾组织（5例肾盂肿瘤患者作为正常对照，17例狼疮性肾炎患者）的阴离子位点进行染色。使用铜啉蓝（CB）作为阳离子探针。进行了超微结构研究和半定量分析。在正常肾小球基底膜（GBM）中，CB可染色的阴离子位点呈现为具有若干短侧支的丝状结构。基于对分离的蛋白聚糖的电子显微镜观察，提示中央细丝为蛋白核心，分支为蛋白聚糖分子的糖胺聚糖。这些丝状阴离子位点主要位于内、外疏松层，彼此靠近形成网状网络模式。对正常GBM的半定量分析显示，外疏松层（LRE）中阴离子位点的数量为22.9±1.9 - 23.7±1.4/1000nm GBM，内疏松层（LRI）中为14.0±1.6 - 15.1±1.5/1000nm GBM。这些发现表明，由硫酸乙酰肝素蛋白聚糖组成的阴离子位点占据了疏松层的大片区域，并阻止阴离子分子的渗透。在5例II类非蛋白尿性狼疮性肾炎患者中，GBM的阴离子位点数量（LRE；21.3±2.0 - 22.3±1.8/1000nm GBM，LRI；13.5±2.0 - 14.2±2.0/1000nm GBM）与正常GBM无显著差异。相反，IV类（6例患者，LRE；14.8±2.7 - 19.3±1.8/1000nm GBM，LRI；5.8±1.9 - 11.3±2.4/1000nm GBM）和V类（6例患者，LRE；13.0±2.4 - 17.9±2.8/1000nm GBM，LRI；12.0±1.9 - 13.0±2.5/1000nm GBM）蛋白尿患者的GBM表现出与免疫沉积物（ID）定位相关的阴离子位点丧失。从这些发现得出结论，在严重和活动性狼疮性肾炎中，GBM电荷屏障的失效是蛋白尿的原因。在狼疮性肾炎患者中观察到的ID未被CB染色。这一发现提示ID的净电荷可能为阳离子，并且阳离子免疫复合物和/或抗体可能参与狼疮性肾炎的发病机制。
