Araki M, Iida Y, Taketani S, Watanabe K, Ohta T, Saito T
Department of Anatomy, Jichi Medical School, Tochigi, Japan.
Dev Biol. 1987 Nov;124(1):239-47. doi: 10.1016/0012-1606(87)90475-1.
Photoreceptor cell differentiation in the rat retina was studied in vivo and in vitro, using an immunohistochemical method to demonstrate opsin-like immunoreactivity. Cells in a dissociated monolayer culture expressed some properties characteristic of rat rod cells developing in vivo, including a ciliary structure and opsin-like immunoreactivity. Immunoblot analysis revealed that cultured retinal cells synthesize a polypeptide with the same molecular weight as that synthesized by the intact retina. Although the outer segment (OS) was not present in the culture, immunoreactive cells possessed a ciliary structure. Opsin-like immunoreactivity was found on the plasma membrane, including the cilia. The neuritic extensions were also intensely stained. In mature rod cells of the intact rat retina, opsin was detected only on the OS but, during development, it was found both in the somatic region of the rod cells and on the differentiating OS. During maturation of rod cells opsin immunoreactivity seemed to shift to the OS from other locations. However, some "displaced" photoreceptor cells, found in the inner nuclear layer and extending fibers bipolarly, retained immunoreactivity throughout their structure. The absence of polarized distribution of opsin in these cells is considered to be due to an abnormal environment, which may also be the case with cultured retinal cells. The present culture conditions will offer a useful model system to understand the cellular mechanism of the hereditary retinal dystrophy of rodent animals in which photoreceptor cells selectively degenerate.
利用免疫组织化学方法来显示视蛋白样免疫反应性，对大鼠视网膜中的光感受器细胞分化进行了体内和体外研究。解离单层培养中的细胞表现出一些在体内发育的大鼠视杆细胞的特征特性，包括纤毛结构和视蛋白样免疫反应性。免疫印迹分析表明，培养的视网膜细胞合成了一种与完整视网膜合成的多肽分子量相同的多肽。尽管培养物中不存在外段（OS），但免疫反应性细胞具有纤毛结构。在包括纤毛在内的质膜上发现了视蛋白样免疫反应性。神经突延伸也被强烈染色。在完整大鼠视网膜的成熟视杆细胞中，仅在外段检测到视蛋白，但在发育过程中，在视杆细胞的体细胞区域和正在分化的外段均发现了视蛋白。在视杆细胞成熟过程中，视蛋白免疫反应性似乎从其他位置转移到了外段。然而，在内核层发现的一些“移位”光感受器细胞并双极延伸纤维，其整个结构都保留了免疫反应性。这些细胞中视蛋白缺乏极化分布被认为是由于异常环境所致，培养的视网膜细胞可能也是这种情况。目前的培养条件将提供一个有用的模型系统，以了解啮齿动物遗传性视网膜营养不良的细胞机制，其中光感受器细胞会选择性退化。
