Ultrastructural changes of extracellular matrices in diabetic nephropathy revealed by high resolution scanning and immunoelectron microscopy.
Ultrastructural changes of extracellular matrices in diabetic nephropathy revealed by high resolution scanning and immunoelectron microscopy.
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发表时间：
1993
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通讯作者：
H. Makino;Y. Yamasaki;T. Haramoto;K. Shikata;K. Hironaka;Z. Ota;Y. Kanwar
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作者：
H. Makino;Y. Yamasaki;T. Haramoto;K. Shikata;K. Hironaka;Z. Ota;Y. Kanwar
背景糖尿病肾病总是与蛋白尿有关。实验设计为了阐明糖尿病肾病蛋白尿的发生机制，应用高分辨扫描和免疫电镜技术研究了肾小球基底膜（GBM）的超微结构变化。从糖尿病和年龄匹配的对照人类受试者的脱细胞肾小球制备的洗涤剂的方法，并进行导电染色，该技术中的组织浸渍与金属，而不是表面涂有金属合金，通过电子显微镜可视化。导电染色后，通过镜头内场发射扫描电子显微镜检查组织。结果对照组和糖尿病组各30个肾小球进行扫描显微镜检查。在糖尿病GBM中，观察到由直径约8nm的许多孔和不同的链组成的松散的网状结构。相比之下，对照组中的网状结构不容易辨别，观察到一些孔。五肾小球毛细血管袢，每个从控制和糖尿病组，通过免疫电镜检查。在对照组中，硫酸乙酰肝素蛋白聚糖定位于内部和外部的稀有层，IV型胶原蛋白分布在整个宽度的GBM。在糖尿病GBM中，观察到GBM的内部和外部稀有层中硫酸乙酰肝素蛋白聚糖染色的相对损失。IV型胶原分布于增厚的GBM各层，免疫金颗粒的绝对数量增加。然而，与对照相比，每单位面积的IV型胶原的免疫金颗粒密度降低。结论：GBM的这些超微结构和免疫电镜改变可以解释在糖尿病肾病伴蛋白尿中观察到的肾小球电荷丢失和大小选择性。
BACKGROUND Diabetic nephropathy is invariably associated with proteinuria. EXPERIMENTAL DESIGN To delineate the mechanism(s) of proteinuria in diabetic nephropathy, ultrastructural changes of the glomerular basement membranes (GBMs) were studied by high resolution scanning and immunoelectron microscopy. Acellular glomeruli from diabetic and age-matched control human subjects were prepared by detergent method and subjected to conductive staining, the technique in which the tissues are impregnated with metals rather than surface-coated with metallic alloys for visualization by electron microscopy. Subsequent to conductive staining, the tissues were examined by in-lens field emission scanning electron microscopy. RESULTS Thirty glomeruli, each from the control and diabetic groups, were examined by scanning microscopy. In diabetic GBMs, a loose meshwork structure consisting of numerous pores of approximately 8 nm in diameter and distinct strands was observed. In contrast, meshwork structure was not readily discernible in controls and a few pores were observed. Five glomerular capillary loops, each from control and diabetic groups, were examined by immunoelectron microscopy. In controls, heparan sulfate-proteoglycan was localized in the lamina rara interna and externa, and type-IV collagen was distributed throughout the whole width of the GBM. In diabetic GBMs, a relative loss of staining of heparan sulfate-proteoglycan, both in the lamina rara interna and externa of the GBM, was observed. Type IV collagen was distributed in all layers of the thickened GBM, and the absolute number of the immunogold particles was increased. However, immunogold particle density of type IV collagen per unit area was decreased as compared with the control. CONCLUSIONS These ultrastructural and immunoelectron microscopic changes in the GBM may explain the loss of charge as well as size selectivities of the glomerulus, as observed in diabetic nephropathy associated with proteinuria.