Morphological study of the retina of salmon (Salmo salar).

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Mario Pellón; Mariana Rojas; Pabla Yaikin & Mariano del Sol


The retina of teleost fish zebrafish, has become an important model for studying neuronal plasticity and neurogenesis. It was further shown that the retina undergoes ontogenetic changes to adapt to different environments during their lifetime. This study aims to describe the ontogenetic development of the retina of juvenile salmon from hatching to the juvenile stage. We worked with 30 salmon divided into three groups of 10. Group I: newly hatched with yolk sac and 18 mm in length. Group II: without yolk sac and 30 mm in length. Group III: 100 mm long. Five fry each group were processed according to the protocol of Hanken & Wassersug to measure dorsoventral and nasal-temporal diameters using the cartilage that protects the eyeball. The remaining five specimens were sectioned with a microtome Microm serially (5 μm) and processed with technical H-E / Alcian blue. The layers of the retina were measured on a Zeiss optical microscope with camera Powershot built and with Image Tool 3.0 software. Group 1 showed large pigmented eyes, looking embryonic optic cup, the retina is stratified in layers. The inner nuclear layer (CNI) measured 62±10 microns and the inner plexiform layer (CPI) 10±2 μm. Group 2 presents changes in the thickness of them. The CNI decreases in thickness to 45±8 μm and the plexiform increased to 25±5 μm. In juvenile fish of group 3, the CNI reaches the minimum thickness (15±3 μm), by contrast, the inner plexiform layer thickness increases up to (70±10 μm). In the three groups observed in the periphery of the retina one proliferative germinative zone, which corresponds to a remnant of the embryonic neural epithelium responsible for the continued growth of the retina. The retina of the salmon can also be an important model for the study of ontogeny, neuronal plasticity and neurogenesis. This retinal neurogenesis fish rearrangement facilitates cell along ontogeny, potentially allowing optimization of the visual system to changes in the visual demands. This study may be useful to help diagnose pathologies in eye salmon and can also contribute to better understand tissue regeneration. On the other hand, with later studies, fish’s retinal neurogenesis could be extrapolated to the treatment of human retinal diseases, such us glaucoma, retinal detachment o diabetic retinopathy.

KEY WORDS: Retina; Eye; Teleost Fish; Salmon; Development.

How to cite this article

PELLÓN, M.; ROJAS, M.; YAIKIN, P. & DEL SOL, M. Morphological study of the retina of salmon (Salmo salar). Int. J. Morphol., 33(2):788-793, 2015.