Cheung P K, Baller J F, Bakker W W
Department of Pathology, University of Groningen, The Netherlands.
Pediatr Nephrol. 1998 Aug;12(6):452-8. doi: 10.1007/s004670050486.
The mechanism by which a human plasma factor associated with proteinuria is able to cause experimental glomerular albumin leakage is unknown. This factor (called 100KF) is able to induce glomerular alterations in the rat kidney, similar to those seen in minimal change disease, including loss of glomerular sialoglycoproteins and decreased expression of glomerular ecto-ATPase. It was previously shown that 100KF is able to stimulate release of reactive oxygen species in inflammatory cells in vitro. This prompted us to test whether 100KF-induced injury is oxygen dependent. The expression of glomerular sialoglycoproteins and ecto-ATPase was evaluated by standard histochemistry and computerized image analysis and expressed in arbitrary units. Rat kidney sections were incubated with or without 100KF under normal or oxygen-poor, i.e., nitrogen, conditions, or with supplementation of superoxide dismutase (SOD, 100 U/ml). The effect of 100KF on glomerular ecto-ATPase was oxygen dependent (32.98+/-2.14 under air vs. 65.20+/-5.53 under nitrogen, P< or =0.01), in contrast to the 100KF-induced loss of glomerular sialoglycoproteins that was not significantly altered under nitrogen (62.67+/-10.08 under air vs. 61.74+/-26.05 under nitrogen). Supplementation of SOD to 100KF solution under normal incubation conditions also suggested oxygen-dependent impairment of glomerular ecto-ATPase. Alternate perfusion ex vivo of the rat kidney with 100KF followed by diluted plasma showed that enhanced leakage of plasma proteins could be inhibited with SOD, indicating oxygen dependency of this 100KF-induced enhanced permeability (60.25+/-19.32 microg urinary albumin/ml after 100KF perfusion vs. 25.23+/-12.05 microg/ml after 100KF plus SOD, P< or =0.01). We conclude that the action of 100KF upon specific glomerular matrix molecules is oxygen dependent, as is the albumin leakage induced by 100KF in the present ex vivo model.
一种与蛋白尿相关的人血浆因子能够导致实验性肾小球白蛋白渗漏的机制尚不清楚。这种因子（称为100KF）能够在大鼠肾脏中诱导肾小球改变，类似于微小病变病中所见的改变，包括肾小球唾液糖蛋白的丢失和肾小球外ATP酶表达的降低。先前已表明100KF能够在体外刺激炎症细胞中活性氧的释放。这促使我们测试100KF诱导的损伤是否依赖于氧气。通过标准组织化学和计算机图像分析评估肾小球唾液糖蛋白和外ATP酶的表达，并以任意单位表示。将大鼠肾脏切片在正常或缺氧（即氮气）条件下与100KF一起孵育，或补充超氧化物歧化酶（SOD，100 U/ml）。100KF对肾小球外ATP酶的作用依赖于氧气（空气中为32.98±2.14，氮气中为65.20±5.53，P≤0.01），而100KF诱导的肾小球唾液糖蛋白丢失在氮气条件下没有显著改变（空气中为62.67±10.08，氮气中为61.74±26.05）。在正常孵育条件下向100KF溶液中补充SOD也提示肾小球外ATP酶存在依赖于氧气的损伤。用100KF然后用稀释血浆对大鼠肾脏进行离体交替灌注表明，SOD可以抑制血浆蛋白渗漏增强，表明这种100KF诱导的通透性增强依赖于氧气（100KF灌注后尿白蛋白为60.25±19.32μg/ml，100KF加SOD后为25.23±12.05μg/ml，P≤0.01）。我们得出结论，在本离体模型中，100KF对特定肾小球基质分子的作用以及100KF诱导的白蛋白渗漏均依赖于氧气。
