Histological stages of retinal morphogenesis in chicken – a descriptive laboratory research

Abstract

The similarity of the developmental anatomy of chicken with that of mammals has rendered it an appropriate animal model for understanding the anatomical and pathological aspects of human biological systems. The present study describes the age-dependent morphological differentiation stages of developing retina of chick embryos. The retinae of chicken embryos of ages 10 and 15 days incubation, of newly hatched chicks and also that of adult chicken were studied histologically. The retinae were processed both for routine microscopy and as araldite-embedded high-resolution sections. At all ages, different retinal layers were studied noting the changing shapes of nuclei and measuring the individual layer thickness. As the animal advances in age, the elongated to oval nuclear shape takes on a more round contour, the pigment content gradually increases, the initial cuboidal cells of the photoreceptor layer change over to tall columnar cells, their outer segments pushing their way into the epithelium layer, producing vacuolar appearances among the pigment granules, the inner and outer plexiform layers increase in thickness, while the nuclear layers, becoming more compact, decrease in thickness. The ganglion cell layer, initially multilayered, gradually becomes single-cell-layered with advancing age. This descriptive laboratory research presents a detailed retinal differentiation pattern, which contributes to the anatomical knowledge of retinal embryology as well as providing a comparative background for pathological deviations.

Retinal Gene Expression of Selective Genes and Histological Stages of Embryonic and Post-Hatch Chickens (Gallus gallus)

“…These retinal layers appeared clearly in all developmental stages except the OPL, which was not observed in eight-day chick embryos but was observed at the other developmental stages. This is consistent with the results of previous studies [ 15 ].…”

“…The retinae of chicken embryos (E8 and E15), newly hatched chicks (P2), and adult chickens (P50) were studied histologically. Our observations of the morphological stages of the retinal layers using H&E staining were consistent with those of previous studies [ 3 , 15 ]. All retinal layers were clearly visible and ordered as follows: the NFL, GCL, IPL, INL, OPL, ONL, and RPE.…”

Investigation of the Effects of Monosodium Glutamate on the Embryonic Development of the Eye in Chickens

“…Kujawa-Hadryś et al [ 101 ] reported that the thickness of the corneal epithelium increased markedly through the end of incubation in chick embryos. Several studies have been conducted examining normal retinal structure in poultry [ 102 , 103 ]. However, there is insufficient information about the effects of MSG on the cornea and retina in chicken embryos.…”

The effect of climatic conditions on malaria epidemics in Swat Valley

“…These areas are at high risk [7]. The reason why malaria emerged and spread is so fast in Pakistan is because of the Afghan refugees who migrated during Soviet War to Pakistan and especially to KP, they didn't have enough facilities and hence they were living in camps, they couldn't use nets for their prevention from the mosquitoes as a result they were prone to the parasite and later 150,000 cases were reported in refugees and the malarial parasite started to appear in the people of Pakistan [8].…”