Efeitos do ambiente enriquecido na morfometria hipocampal em ratos submetidos a crises convulsivas e a desnutrição no período neonatal

• Autor(a) principal: Alvarez, Paula Steffen
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/1733
• topic: MEDICINA; DESNUTRIÇÃO; EPILEPSIA; CONVULSÕES; HIPOCAMPO; CNPQ::CIENCIAS DA SAUDE::MEDICINA

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.