Galbavy E S, Olson M D
Anat Rec. 1979 Dec;195(4):707-17. doi: 10.1002/ar.1091950410.
This study presents scanning electron microscopic (SEM) observations of topographical changes that occur during morphogenesis of rod cells in the albino rat. Correlative transmission electron microscopy (TEM) was also utilized. Albino rats ranging in age from birth to three weeks were used for the study. Tissues were prepared by conventional methods for SEM and TEM. At birth, numerous irregularly arranged inner segments extend from the external surface of the sensory retina. They are spherical, smooth surfaced and possess a randomly oriented cilium. The internal morphology of these immature inner segments is comparable to that observed in other vertebrate species. Statistical analysis reveals a rapid increse in the number of rod cells during the first week. This period is characterized by the elongation of inner segments and their associated cilia. Microvilli project from the apices of Müller cells, but not from adjacent inner segments. By day 5, cilia occasionally display small bulbous outer segments. They are more numerous by day 8 and are usually eccentrically positioned at the tips of cilia. By day 11, outer segments are abundant and frequently obscure from view the underlying inner segments and associated cilia. Elongated cylindrical outer segments are present within the posterior retina at the end of the second week. However, rod cell morphogenesis lags in the peripheral retina. Topographical variations between developing photoreceptor cells in mammalian and non-mammalian retinas are discussed.
本研究展示了对白化大鼠视杆细胞形态发生过程中地形变化的扫描电子显微镜（SEM）观察结果。同时也运用了相关的透射电子显微镜（TEM）。研究使用了年龄从出生到三周的白化大鼠。组织通过常规方法制备用于SEM和TEM观察。出生时，许多排列不规则的内节从感觉视网膜的外表面伸出。它们呈球形，表面光滑，有一根随机定向的纤毛。这些未成熟内节的内部形态与在其他脊椎动物物种中观察到的相似。统计分析显示，在第一周视杆细胞数量迅速增加。这一时期的特征是内节及其相关纤毛的伸长。微绒毛从穆勒细胞的顶端伸出，但不从相邻的内节伸出。到第5天，纤毛偶尔会显示出小的球状外节。到第8天，外节数量更多，通常偏心地位于纤毛顶端。到第11天，外节丰富，常常遮挡住下方的内节及其相关纤毛。在第二周结束时，细长的圆柱形外节出现在视网膜后部。然而，视杆细胞的形态发生在周边视网膜中滞后。文中讨论了哺乳动物和非哺乳动物视网膜中发育中的光感受器细胞之间的地形差异。
