Washizawa K, Ishii K, Itoh N, Mori T, Akabane T, Shigematsu H
Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.
Acta Pathol Jpn. 1989 Sep;39(9):558-65. doi: 10.1111/j.1440-1827.1989.tb02484.x.
Changes in glomerular anionic sites were examined morphometrically in nephrotic rats receiving daily subcutaneous injections of puromycin aminonucleoside (PAN). The high-iron diamine-thiocarbohydrazide-silver proteinate method showed that anionic sites composed of heparan sulfate proteoglycans formed a continuous band within the lamina rara externa of the glomerular basement membrane (GBM) in control rats. Only one day after the first injection of PAN, anionic site loss was already detectable, preceding the morphological changes in the epithelial cells. The number and size of the anionic sites decreased greatly between days 7 and 10, when urinary protein excretion began to appear. The number of anionic sites in the paramesangial regions (epithelial side of the mesangium) was slightly more reduced than that in the capillary walls. These results suggested that PAN directly injured the glomerular anionic sites and increased the permeability of the glomerulus to macromolecules. However, there was no complete correlation between the number of lost anionic sites and the level of urinary protein excretion. Thus protein excretion into the urinary space may be related not only to the loss of subepithelial anionic sites but also to dysfunction of the protein absorption mechanism in epithelial cells due to excessive permeation of macromolecules through the GBM.
采用形态计量学方法，对每日皮下注射嘌呤霉素氨基核苷（PAN）的肾病大鼠肾小球阴离子位点的变化进行了研究。高铁二胺-硫代碳酰肼-银蛋白法显示，在对照大鼠中，由硫酸乙酰肝素蛋白聚糖组成的阴离子位点在肾小球基底膜（GBM）的外疏松层内形成一条连续带。首次注射PAN后仅一天，即可检测到阴离子位点的丢失，且早于上皮细胞的形态学变化。在第7天至第10天期间，当尿蛋白排泄开始出现时，阴离子位点的数量和大小大幅减少。系膜旁区（系膜上皮侧）的阴离子位点数量比毛细血管壁的减少略多。这些结果表明，PAN直接损伤肾小球阴离子位点，并增加肾小球对大分子的通透性。然而，丢失的阴离子位点数量与尿蛋白排泄水平之间并无完全相关性。因此，蛋白排泄到尿腔中可能不仅与上皮下阴离子位点丢失有关，还与大分子通过GBM过度渗透导致上皮细胞蛋白吸收机制功能障碍有关。
