Immunohistochemical Localization Of The Neurofilament Protein Antibody RT97 In The Retina And The Brain Of Zebrafish In The Development

Based on the histological study of the development of retina and brain in zebrafish, the spatio-temporal distribution of neurofilament identified by RT97 was investigated in the retina and brain during zebrafish development by the immunohistochemical method. The specificity of mammalian RT97 antibody to zebrafish visual tissue was confirmed using Western blot.The histological study demonstrated that the development pattern of the zebrafish retina and brain was similar to that of the vertebrates. The optic primordial formed from the protrusion of the anterior neural tube and the optic primordial enlarged into the optic vesicle with the cell proliferation in it. Then the optic vesicle extended and transformed into the optic cup with the inner layer and the outer layer that differentiated into the neural retina and pigmented retina respectively. The retina with ten layers formed in adult zebrafish . The early development of brain was initiated at 12 hours postfertilization, after the original segment of brain vesicle, three primordial cell groups eventually formed the telencephalon, diencephalon, mesencephalon and cerebellum; the development of the brain completed and the function formed accompanying the migration and differentiation of the cells.Western blot results showed that the mammalian RT97 antibody has specificity to visual tissue of zebrafish; For the development of the retina, the immunohistochemical results indicated that a few weak RT97 positive appeared at optic vesicle stage; some inner layer cells (neural retina) presented slightly strong RT97 immunoreactivity at optic cup stage; RT97 immunoreactivity was mainly observed in outer region of retina layers at the otolith formation stage; RT97 antibody intensely stained cell bodies in retinal CMZ from retinal pigmentation to hatching stage; weak RT97 immunoreactivity appeared in IPL while the intense RT97 immunoreactivity was mainly located in ON, OC and IB 4 days after hatching; in adult retina, strong RT97 immunoreactivity existed in NFL and ON, while weak reaction was present in IPL and OPL. For the development of brain, 14 hours post fertilization, a few weak positive cells were observed in the forehead region; 30-60 hours post fertilization, some cells in tectum have strong positive immunoreactivity and accumulated gradually; the positive cells appeared in the region of telencephalon, hypothalamus, tegmentum, cerebellum, and rhombencephalon; 7d and 15d post fertilization, the cerebellum partial neurite, the majority of fibers of tegmentum telencephalon and rhombencephalon, optic tract located in diencephalons presented the strong RT97 immunoreactivity; 1month post fertilization, the strong positive fiber was observed in the SM and SPV of tectum and optic tract, the fibers in hypothalamus, tegmentum and cerebellum presented relatively strong immunoreactivity; the strong RT97 immunoreactivity was observed in fiber of SM,cerebellum and hypothalamus in adult. These results suggest that the neurofilament proteins identified by RT97, during the development, could be involved in the different function of retina and brain, in early period it may be related to the morphogenesis of retina and brain, while after hatching it may be related to the growth of axon. The experiment will provide the evidence of biochemistry and morphology for illuminating neurofilament function in the early morphogenesis of nervous system and disclosuring molecular biology mechanics of vertebrate nervous system development.