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Previous issue date: 2013-03-25 / Introduction: It has been recently shown that enriched environment leads to a significant benefit in learning and retention of visual-spatial memory, being able to reverse the cognitive impairment generated by undernourishment and seizures. Considering the role of the hippocampus in memory/learning, we investigated the effects of the enriched environment on hippocampal morphometry of rats submitted to recurrent seizures and undernourishment in the neonatal period. Methods: Male offspring of rats were allocated on 8 experimental groups Nourished controls (N), Nourished with Recurrent Seizures (N + RS), Nourished with Enriched Environment (N + EE); Nourished with Recurrent Seizures and Enriched Environment (N + RS + EE), Undernourished Controls (U), Undernourished with Convulsive Crisis (U + CC), Undernourished with Enriched Environment (U + EE); Undernourished with Recurrent Seizures and Enriched Environment (U + RS + EE). Undernourished groups were maintained on a regimen of food deprivation by progressive removal of the second lactating female (P2) to the fifteenth (P15), an increase of 2 hours a day up to a total 12 hours, which was kept maximum spacing until end undernourishment. Between P8 and P10, groups with recurrent Seizures were exposed to three recurrent seizures per day induced by flurothyl. Between P21 and P51 all animals with an enriched environment were exposed to it. At P51 all animals were sacrificed by transcardiac perfusion. We evaluated the volume of the hippocampus using the grid points methodology. Neuronal and glial densities, hippocampal volume and CA1 subfield thickness were calculated based on the two-dimensional quantitative system for test points created by Image Pro Plus 6.0 software (Media Cybernetics Capture, USA). Results: Undernourisment during early development decreased neuronal density in the CA1 and CA3 subfield, as well as in the glial density in CA1 subfield. In parallel, recurrent seizures promoted a decrease in the glial density in CA1 and CA3 area. The animals submitted to the enriched environment show an increased hippocampal volume and thickness of layer of CA1. Conclusions: Pathological findings, with onset in the early stages of undernourishment and epilepsy may be a significant factor in comorbidities, such as cognitive dysfunction found in patients with epilepsy and malnutrition. Taking these findings together, we can assume that environment stimulation beginning early in life may play a critical role in improving the structural brain development and hence cognitive functioning. / Introdu??o: Recentemente mostrou-se que o enriquecimento ambiental promove significativa melhora na aprendizagem e reten??o de mem?ria visual-espacial, sendo capaz de reverter a disfun??o cognitiva gerada por subnutri??o e crises convulsivas. Considerando o papel do hipocampo na mem?ria/aprendizagem, investigamos os efeitos do ambiente enriquecido sobre a morfometria do hipocampo de ratos submetidos a crises recorrentes e desnutri??o no per?odo neonatal. M?todos: Filhotes machos de ratos Wistar foram alocados em 8 grupos: Nutridos Controles (N), Nutridos com Crise Convulsiva (N+CC), Nutridos com Ambiente Enriquecido (N+AE); Nutridos com Crises convulsiva e Ambiente Enriquecido (N+CC+AE), Desnutridos Controles (D), Desnutridos com Crise Convulsiva (D+CC), Desnutridos com Ambiente Enriquecido (D+AE); Desnutridos com Crises convulsiva e Ambiente Enriquecido (N+CC+AE). Os animais dos grupo desnutridos foram mantidos em um regime de priva??o alimentar progressivo por afastamento da f?mea nutriz do segundo (P2) ao d?cimo quinto (P15), aumentando 2 horas por dia at? totalizar 12 horas, per?odo m?ximo que foi mantido o afastamento at? o fim da desnutri??o. Entre P8 e P10, os grupos com crises convulsivas foram expostos diariamente a tr?s crises recorrentes induzidas por flurotil. Entre P21 e P51 os animais dos com ambiente enriquecido foram expostos ao mesmo. Em P51 todos animais foram sacrificados por perfus?o Transcard?aca. Foi avaliado o volume do Hipocampo atrav?s da metodologia de grade de pontos. As densidades neuronais e gliais nas subregi?es CA1 e CA3 e a espessura da subregi?o CA1 foram calculadas a partir do sistema quantitativo bidimensional, por teste de pontos criado pelo software Image Pro Plus 6.0 (Capture Media Cybernetics, USA). Resultados: A desnutri??o durante o desenvolvimento inicial reduziu a densidade neuronal nos subregi?es CA1 e CA3, bem como promoveu uma diminui??o na densidade de c?lulas gliais em CA1. Em paralelo, as crises convulsivas promoveram uma diminui??o na densidade de c?lulas gliais em CA1 e CA3. Os animais submetidos ao ambiente enriquecido apresentaram um aumento de volume do hipocampo e da espessura da camada de CA1. Conclus?es: Os achados do presente estudo sugerem que a estimula??o ambiental no in?cio da vida pode desempenhar um papel fundamental na melhoria do desenvolvimento estrutural do c?rebro e, consequentemente, do seu funcionamento cognitivo.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/1733 |
| Date | 25 March 2013 |
| Creators | Alvarez, Paula Steffen |
| Contributors | Nunes, Magda Lahorgue |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Medicina e Ci?ncias da Sa?de, PUCRS, BR, Faculdade de Medicina |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 7620745074616285884, 500, 600, -8624664729441623247 |
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