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Adult neurogenesis in a new model specie, the cichlid fish Oreochromis mossambicus
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Abstract(s)
Em comparação com outros vertebrados, os peixes teleósteos têm um enorme potencial para produzir células novas no cérebro de animais adultos. Em contraste com os mamíferos, onde o processo de neurogénese adulta encontra-se restrito a duas áreas cerebrais, a zona subventricular (SVZ) e a zona subgranular parte do giro dentado do hipocampo, em peixes teleósteos foram descritas mais de 10 regiões neurogénicas. Através da marcação de células mitóticas com 5-bromo-2’-deoxiuridina (BrdU), foram caracterizadas as zonas proliferativas da Tilapia de Moçambique (Oreochromis mossanbicus). Nesta espécies, foram encontradas zonas proliferativas em regiões específicas do bolbos olfactivo, telecéfalo, região pré-optica, hipotálamo, tálamo, tecto óptico, torus longitudinalis, nas três divisões do cerebelo, valvula cerebelli, corpus cerebelli, e lobus caudalis e na região da medula, abrangendo assim toda a extensão cerebral. A localização destas zonas proliferativas parece ser extremamente conservada ao longo da taxonomia e até o número total de células produzidas parece ser mantido com pouca variação. Com um tempo de sobrevivência de 2 horas, foram encontrados na tilapia um total de 80.000 células novas em comparação com as 100.000 descritas para o peixe eléctrico Apteronotus leptorhynchus. Os nossos resultados sugerem que a actividade mitótica em regiões discretas do cérebro adulto são uma característica primitiva que tem sido conservada ao longo da evolução.
ABSTRACT: Compared to other vertebrate species, fish exhibit an enormous potential to produce new cells in the adult brain. In contrast to mammals, where proliferation zones are restricted to two brain areas, the sub ventricular zone (SVZ), and the subgranular zone (SGZ), part of the dentate gyrus of hippocampus, in teleost species more than 10 neurogenic regions have been described. By labeling mitotically dividing cells with 5-bromo-2'-deoxyuridine (BrdU), we have characterized the proliferation zones in the Mozambique tilapia (Oreochromis mossambicus). Proliferation zones were located in specific brain regions of the olfactory bulb, telencephalon, preoptic area, hypothalamus, thalamus, optic tectum, torus longitudinalis, in all three subdivisions of the cerebellum, the valvula cerebelli, the corpus cerebelli, and the lobus caudalis cerebelli and in the region of the medulla oblongata. These proliferation zones appeared to be extremely conserved across taxonomy and even the total number of new generated cells seems to be preserved. After 2 hours survival time we found a total of approximately 80.000 new cells for tilapia compared to 100.000 new cells described for Apteronotus leptorhynchus. Our results suggest that the presence of mitotic activity in specific brain regions is a primitive feature that has been conserved through evolution.
ABSTRACT: Compared to other vertebrate species, fish exhibit an enormous potential to produce new cells in the adult brain. In contrast to mammals, where proliferation zones are restricted to two brain areas, the sub ventricular zone (SVZ), and the subgranular zone (SGZ), part of the dentate gyrus of hippocampus, in teleost species more than 10 neurogenic regions have been described. By labeling mitotically dividing cells with 5-bromo-2'-deoxyuridine (BrdU), we have characterized the proliferation zones in the Mozambique tilapia (Oreochromis mossambicus). Proliferation zones were located in specific brain regions of the olfactory bulb, telencephalon, preoptic area, hypothalamus, thalamus, optic tectum, torus longitudinalis, in all three subdivisions of the cerebellum, the valvula cerebelli, the corpus cerebelli, and the lobus caudalis cerebelli and in the region of the medulla oblongata. These proliferation zones appeared to be extremely conserved across taxonomy and even the total number of new generated cells seems to be preserved. After 2 hours survival time we found a total of approximately 80.000 new cells for tilapia compared to 100.000 new cells described for Apteronotus leptorhynchus. Our results suggest that the presence of mitotic activity in specific brain regions is a primitive feature that has been conserved through evolution.
Description
Dissertação de Mestrado apresentada ao ISPA - Instituto Universitário
Keywords
Tilápia de Moçambique Neurogénese adulta Bolbos olfactivos Telencéfalo Tecto óptico Cerebelo BrdU Peixes teleósteos Mozambique tilapia Adult neurogenesis Olfactory bulb Telencephalon Optic tectum Cerebellum Teleost fish