Korte G E, Mrowiec E, Landzberg K S, Youssri A
Department of Ophthalmology, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY, USA.
Exp Eye Res. 1995 Aug;61(2):189-203. doi: 10.1016/s0014-4835(05)80039-9.
Retinal pigment epithelium (RPE) regenerating after experimental damage in rabbits exhibits major changes in cell shape, polarity and junctions--features that depend on the cytoskeleton. This report correlates these changes with the redistribution of actin microfilaments and microtubules, using electron microscopy and confocal laser scanning microscopy. We compare immature cells with the more mature cells that form the new epithelial monolayer. Two populations of immature RPE cells are interspersed at the edge of the regenerating RPE sheet. One population of immature cells makes few junctions with their neighbors or the basement membrane. They form pseudopodia and exhibit a prominent network of actin microfilaments beneath the plasma membrane. These cells are probably motile and advance the epithelial sheet. Another population of immature cells contains numerous stress fibers that insert into large basement membrane attachments. The cells make focal adhesions with their neighbors, rather than the junctional complexes characteristic of mature RPE cells. These cells are probably not motile and mature into the cells forming the new monolayer--cuboidal cells with numerous basal folds and apical villi and a complete belt of intercellular junctions. Stress fibers are lost as the circumferential bundle associated with the zonula adherens re-forms. Microtubules, which form prominent longitudinal bundles running through the processes of immature cells, take on the meshwork organization characteristic of mature RPE as the immature cells differentiate.
兔视网膜色素上皮（RPE）在实验性损伤后再生时，细胞形状、极性和连接会发生重大变化，这些特征取决于细胞骨架。本报告利用电子显微镜和共聚焦激光扫描显微镜，将这些变化与肌动蛋白微丝和微管的重新分布联系起来。我们将未成熟细胞与形成新上皮单层的更成熟细胞进行比较。在再生的RPE片边缘散布着两类未成熟的RPE细胞。一类未成熟细胞与其相邻细胞或基底膜形成的连接很少。它们形成伪足，并在质膜下方展现出明显的肌动蛋白微丝网络。这些细胞可能具有运动能力，并推动上皮片的生长。另一类未成熟细胞含有大量插入大型基底膜附着点的应力纤维。这些细胞与其相邻细胞形成粘着斑，而非成熟RPE细胞特有的连接复合体。这些细胞可能不具有运动能力，并会成熟为形成新单层的细胞，即具有大量基底褶皱和顶端绒毛以及完整细胞间连接带的立方体细胞。随着与紧密连接相关的周向束重新形成，应力纤维消失。在未成熟细胞分化过程中，贯穿未成熟细胞突起形成明显纵向束的微管，呈现出成熟RPE特有的网络状结构。
