Kitamura H, Shimizu A, Masuda Y, Ishizaki M, Sugisaki Y, Yamanaka N
Department of Pathology, Nippon Medical School, Tokyo, Japan.
Exp Nephrol. 1998 Jul-Aug;6(4):328-36. doi: 10.1159/000020540.
Capillary obsolescence with subsequent glomerulosclerosis is a common finding in most progressive glomerular diseases. In this study we investigated apoptosis, focusing on glomerular endothelial cells during the development of glomerulosclerosis in five-sixths nephrectomized rats for 6 months. Apoptosis was recognized by light and electron microscopy. Biochemical labeling of apoptosis was morphologically confirmed by in situ end labeling of fragmented DNA using terminal deoxynucleotidyltransferase. Glomerular endothelial cells were identified by electron microscope and immunostaining for thrombomodulin which is known to be an endothelial cell surface glycoprotein. Glomerular hypercellularity occurred by month 2, peaking by month 3, and an extracellular matrix accumulation was evident by month 3. Subsequently, most of the glomeruli progressed to diffuse sclerosis by months 4-6. During the progression of the disease, the glomerular endothelial cells decreased in number and finally could not be detected in the sclerotic lesion, and apoptotic cells apparently increased in number in the lesion. Significant apoptosis was present from month 3, thereafter it gradually increased to peak by month 6. Double immunostaining for apoptosis and thrombomodulin demonstrated that apoptosis occurred in the glomerular endothelial cells as well as in mesangial cells and infiltrating cells. The number of glomerular endothelial cells with apoptosis increased with the development of glomerulosclerosis, and maximum expression was observed by month 6. We conclude that the depletion of glomerular endothelial cells is associated with apoptosis in the remnant-kidney model, and apoptosis in glomerular endothelial cells may contribute to the development of glomerulosclerosis.
毛细血管荒废伴随后续的肾小球硬化是大多数进行性肾小球疾病的常见表现。在本研究中，我们对六分之五肾切除大鼠6个月肾小球硬化发展过程中的细胞凋亡进行了研究，重点关注肾小球内皮细胞。通过光镜和电镜识别细胞凋亡。使用末端脱氧核苷酸转移酶对断裂DNA进行原位末端标记，从形态学上证实了细胞凋亡的生化标记。通过电子显微镜和对血栓调节蛋白（已知为内皮细胞表面糖蛋白）的免疫染色来识别肾小球内皮细胞。肾小球细胞增多在第2个月出现，第3个月达到峰值，细胞外基质积累在第3个月明显可见。随后，大多数肾小球在4至6个月时进展为弥漫性硬化。在疾病进展过程中，肾小球内皮细胞数量减少，最终在硬化病变中无法检测到，而病变中的凋亡细胞数量明显增加。从第3个月开始出现明显的细胞凋亡，此后逐渐增加，到第6个月达到峰值。凋亡和血栓调节蛋白的双重免疫染色表明，凋亡发生在肾小球内皮细胞以及系膜细胞和浸润细胞中。随着肾小球硬化的发展，发生凋亡的肾小球内皮细胞数量增加，在第6个月观察到最大表达。我们得出结论，在残余肾模型中，肾小球内皮细胞的耗竭与细胞凋亡有关，肾小球内皮细胞的凋亡可能促成肾小球硬化的发展。
