Noske W, Levarlet B, Kreusel K M, Fromm M, Hirsch M
Augenklinik, Klinikum Steglitz, Freie Universität Berlin, Germany.
Graefes Arch Clin Exp Ophthalmol. 1994 Oct;232(10):608-13. doi: 10.1007/BF00193121.
Intramembrane specializations of cultured bovine corneal endothelial cells were studied with thin section and freeze-fracture electron microscopy and related to the paracellular permeability and the transendothelial resistance (Rt) of the monolayers. The following intercellular junctions were found: single and discontinuous networks of tight junctions (TJ) which girdle the apico-lateral cell perimeter incompletely, gap junctions, and membrane undulations suggesting intermediate junctions. The macromolecular tracer ruthenium red penetrated into the lateral intercellular space beyond the level of the incomplete belt of TJ. Rt of these monolayers was 20.9 +/- 1.0 omega.cm2. Protamine induced a reversible increase of Rt to 118 +/- 5% of its control value. We conclude that incomplete belts of TJ may be the morphological counterpart of the high paracellular permeability of this monolayer and functionally and morphologically resemble those of their native endothelium. Cultured corneal endothelial cells are an excellent model for studying the influence of incomplete belts of TJ on paracellular permeability of cells.
利用超薄切片和冷冻蚀刻电子显微镜技术研究了培养的牛角膜内皮细胞的膜内特化结构，并将其与单层细胞的细胞旁通透性和跨内皮电阻（Rt）相关联。发现了以下细胞间连接：紧密连接（TJ）的单个和不连续网络，其不完全环绕细胞顶端-侧面周边；缝隙连接；以及提示中间连接的膜波动。大分子示踪剂钌红渗透到不完全TJ带水平之外的细胞间侧间隙中。这些单层细胞的Rt为20.9±1.0Ω·cm²。鱼精蛋白诱导Rt可逆性增加至其对照值的118±5%。我们得出结论，不完全的TJ带可能是该单层细胞高细胞旁通透性的形态学对应物，在功能和形态上类似于其天然内皮细胞的TJ带。培养的角膜内皮细胞是研究不完全TJ带对细胞间旁通透性影响的极佳模型。
