Temporospatial dynamics of the morphogenesis of the rabbit retina from prenatal to postnatal life: Light and electron microscopic study

• Published in: Microscopy research and technique 2024-04, Vol.87 (4), p.774-789
• Main Authors: El‐Desoky, Sara M. M., Elhanbaly, Ruwaida, Hifny, Abdalla, Ibrahim, Nagwa, Gaber, Wafaa
• Format: Article
• Language: English
• Subjects: Amacrine cells; Calretinin; Cell differentiation; Cytoplasm; Dendrites; Differentiation; Electron microscopy; Embryogenesis; Gestation; Gliogenesis; Horizontal cells; Immunoreactivity; Membranes; Morphogenesis; Mueller cells; muller cells; optic cup; Photoreception; Photoreceptors; Prenatal development; Primordia; Proteins; Rabbits; Retina; S100; S100 protein; Segments
• ISSN: 1059-910X; 1097-0029
• DOI: 10.1002/jemt.24466

The retina consists of various cell types arranged in eight cell layers and two membranes that originate from the neuroectodermal cells. In this study, the timing of differentiation and distribution of the cellular components and the layers of the rabbit retina are investigated using light and electron microscopy and immunohistochemical techniques. There were 32 rabbit embryos and 12 rabbits used. The rabbit retina begins its prenatal development on the 10th day of gestation in the form of optic cup. The process of neuro‐ and gliogenesis occurs in several stages: In the first stage, the ganglionic cells are differentiated at the 15th day. The second stage includes the differentiation of Muller, amacrine, and cone cells on the 23rd day. The differentiation of bipolar, horizontal, and rod cells and formation of the inner segments of the photoreceptors consider the late stage that occurs by the 27th and 30th day of gestation. On the first week of age postnatally, the outer segments of the photoreceptors are developed. S100 protein is expressed by the Muller cells and its processes that traverse the retina from the outer to the inner limiting membranes. Calretinin is intensely labeled within the amacrine and displaced amacrine cells. Ganglionic cells exhibited moderate immunoreactivity for calretinin confined to their cytoplasm and dendrites. In conclusion, all stages of neuro‐ and gliogenesis of the rabbit retina occur during the embryonic period. Then, the retina continues its development postnatally by formation of the photoreceptor outer segments and all layers of the retina become established. Research Highlights The aim of this study is to investigate the morphogenesis of the rabbit retina during pre‐ and postnatal life. The primordia of the retina could be observed in the form of the optic cup. The ganglionic cells are the first cells to differentiate, while the photoreceptor cells are the last. S100 protein is expressed by the Muller cells and its processes. Calretinin is intensely labeled in the amacrine and displaced amacrine cells and moderately expressed in the cytoplasm and dendrites of ganglionic cells. Prenatal (A–G) and postnatal (H–L) rabbit retinas showing retinal morphogenesis. Optic cup (arrowhead), diencephalon (asterisk), optic stalk (arrow), nerve fiber layer (yellow arrow), ganglionic cell layer (GCL), neuroblastic cells (N), inner nuclear layer (INL), outer nuclear layer (ONL), immunoreactive ganglionic cells (red arrow), and amacrine