Hora K
2nd Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
Nihon Jinzo Gakkai Shi. 1991 Sep;33(9):839-48.
The ultrastructural features of isolated normal rat glomeruli were investigated using a new splitting technique and the quick-freezing and deep-etching (QF-DE) method. Examinations were also made of in vivo normal rat glomeruli by the QF-DE method to visualize the glomeruli under near natural conditions. Freeze-fractured capillary loops were observed from the capillary lumen or the urinary space. Foot processes were found to be freeze-fractured horizontally, obliquely or vertically to the glomerular basement membrane (GBM), and a glomerular slit diaphragm, which consisted of sheet-like, ladder-like and zipper-like substructures, was clearly identified. The GBM was classified into three zones, which might correspond to those seen in ultrathin sections, including the lamina densa and laminae rarae externa and interna. The lamina densa was composed of a meshwork filled with fine particles, which might represent products of insoluble proteins. In the laminae rarae, filamentous structures consisting of irregular networks could be observed connecting glomerular endothelial or epithelial cells with the lamina densa. Furthermore, the above findings were obtained from investigations at various consecutive levels of freeze-fractured capillary loops from various angles. The three-dimensional ultrastructure of the glomeruli could be demonstrated at high resolution by the QF-DE method.
采用一种新的分离技术以及快速冷冻和深度蚀刻（QF-DE）方法，对分离出的正常大鼠肾小球的超微结构特征进行了研究。还通过QF-DE方法对体内正常大鼠肾小球进行了检查，以在接近自然的条件下观察肾小球。从毛细血管腔或尿腔观察到冷冻断裂的毛细血管袢。发现足突相对于肾小球基底膜（GBM）呈水平、倾斜或垂直方向的冷冻断裂，并且清晰地识别出由片状、梯状和拉链状亚结构组成的肾小球裂孔隔膜。GBM可分为三个区域，这可能与超薄切片中所见的区域相对应，包括致密层以及内、外疏松层。致密层由充满细颗粒的网络组成，这些细颗粒可能代表不溶性蛋白质的产物。在疏松层中，可以观察到由不规则网络组成的丝状结构，将肾小球内皮细胞或上皮细胞与致密层连接起来。此外，上述发现是通过从不同角度对冷冻断裂的毛细血管袢的各个连续层面进行研究而获得的。通过QF-DE方法可以高分辨率地展示肾小球的三维超微结构。
