King B F
Anat Rec. 1982 May;203(1):73-82. doi: 10.1002/ar.1092030108.
Cell surface specializations and intercellular junctions of human term amniotic epithelium were examined by conventional thin-section electron microscopy, after staining with the cationic probes ruthenium red and cationic ferritin, and by freeze-fracture methods. Desmosomes were the predominant type of intercellular junction and often the most apical of the junctional types. In freeze-fracture replicas, desmosomes were characterized by roughly circular areas of large, often irregular, P-face intramembranous particles. Gap junctions were identified in the laterobasal regions between cells. In thin sections they were characterized by a narrow intercellular space, and in freeze-fracture replicas had a typical plaquelike arrangement of P-face intramembranous particles and E-face depressions. Hemidesmosomes at the basal cell surface were characterized by occasional large particles and clusters of particles on both the E and P fracture faces. No evidence of tight junctions was found. The apical cell surface was heavily stained by both ruthenium red and cationic ferritin, indicating the negatively charged nature of this surface. Ruthenium red penetrated between the epithelial cells and bound to anionic materials on the lateral cell surfaces, especially at the location of desmosomes. Below the base of the intercellular cleft, large ruthenium red-positive granules were present in the extracellular matrix. The possibility that the anionic substances in the intercellular region may contribute to the control of permeability in the amniotic epithelium is discussed.
采用常规超薄切片电子显微镜技术、阳离子探针钌红和阳离子铁蛋白染色后以及冷冻蚀刻方法，对人足月羊膜上皮细胞的细胞表面特化结构和细胞间连接进行了研究。桥粒是主要的细胞间连接类型，且常常是连接类型中最靠近顶端的。在冷冻蚀刻复制品中，桥粒的特征是在P面有大致呈圆形的区域，其中有大的、通常不规则的膜内颗粒。缝隙连接在细胞间的侧基区域被识别。在超薄切片中，它们的特征是细胞间间隙狭窄，在冷冻蚀刻复制品中，P面膜内颗粒和E面凹陷呈典型的斑块状排列。基底细胞表面的半桥粒在E面和P面断裂面上均有偶尔出现的大颗粒和颗粒簇。未发现紧密连接的证据。顶端细胞表面被钌红和阳离子铁蛋白强烈染色，表明该表面带负电荷。钌红渗透到上皮细胞之间，并与细胞侧面的阴离子物质结合，尤其是在桥粒的位置。在细胞间裂隙底部下方，细胞外基质中存在大量钌红阳性颗粒。讨论了细胞间区域的阴离子物质可能有助于控制羊膜上皮通透性的可能性。
