Caldwell R B, McLaughlin B J
Exp Eye Res. 1983 Mar;36(3):415-27. doi: 10.1016/0014-4835(83)90123-9.
We have studied permeability of retinal pigment epithelial (RPE) cell junctions in Royal College of Surgeons rats with inherited retinal degeneration, and their genetic controls, using the horseradish peroxidase and lanthanum nitrate electron microscope tracer techniques. We find that early in the dystrophic process, at two postnatal weeks in the pink-eyed retina and three postnatal weeks in the black-eyed retina, RPE cell tight junctions form a barrier to extracellular tracer. However, at three postnatal weeks in the pink-eyed retina, at about the same time that degenerating photoreceptor nuclei begin to appear, RPE cell tight junctions become permeable. The permeability increase occurs later in the black-eyed strain, but by six postnatal weeks junctions are permeable in both strains. By 72 postnatal days, when most photoreceptor nuclei have disappeared, many RPE cells are abnormal in shape, with an elongated and flattened appearance, and some appear to have lost their junctions entirely. In the horseradish peroxidase experiments, many pinocytotic vesicles filled with reaction product were observed in the dystrophic RPE after the junctional breakdown. This suggests that an increase in transcellular transport may also occur in the dystrophic RPE.
我们利用辣根过氧化物酶和硝酸镧电子显微镜示踪技术，研究了患有遗传性视网膜变性的皇家外科学院大鼠视网膜色素上皮（RPE）细胞连接的通透性及其遗传控制。我们发现，在营养不良过程的早期，即在出生后两周的红眼视网膜和出生后三周的黑眼视网膜中，RPE细胞紧密连接对细胞外示踪剂形成了屏障。然而，在出生后三周的红眼视网膜中，大约在退化的光感受器细胞核开始出现的同时，RPE细胞紧密连接变得具有通透性。通透性增加在黑眼品系中出现得较晚，但到出生后六周时，两个品系的连接都具有通透性。到出生后72天，当大多数光感受器细胞核消失时，许多RPE细胞形状异常，呈细长扁平状，有些似乎完全失去了连接。在辣根过氧化物酶实验中，在连接破坏后，在营养不良的RPE中观察到许多充满反应产物的胞饮小泡。这表明在营养不良的RPE中也可能发生跨细胞转运增加。
