Avaliação da morfologia cerebral e do desempenho motor de ratos sedentários e exercitados submetidos à isquemia cerebral transitória

• Autor(a) principal: Damázio, Laila Cristina Moreira
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/267
• topic: Exercicio fisico; Neuroproteção; Isquemia cerebral; Physical exercise; Neuroprotection; Cerebral ischemia; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Physical exercise has been used in the prevention and rehabilitation of patients affected by cerebral ischemia, however, the mechanism by which exercise promotes neuroprotection and neuronal plasticity is not yet fully known. This study aims to analyze the motor performance, the volume of cerebral infarction, the density of astrocytes and neurons in the striatum, in the apex of the dentate gyrus of the hippocampus and in the motor cortex of rats that performed exercise before and/or after cerebral ischemia. Forty-eight Wistar male rats (Body weight: 138g; Age: 30 days) were randomly divided into two groups: transient occlusion of the middle cerebral artery (MCAO); sham surgery with no ischemia. Then, both groups were subdivided into: rats submitted to exercise training prior to sham surgery and MCAO (AI and AC, n = 12); rats submitted to exercise training prior and after sham surgery and MCAO (ADI and ADC, n = 12); rats submitted to exercise training after sham surgery and MCAO (DI and DC, n = 12); and rats not submitted to exercise (SI and SC, n = 12). Exercise training was performed on a motor driven treadmill at the speed of 15 or 12 m/min., 5 days/wk, 30 min/day for 6 weeks. Motor performance was assessed by motor function tests, foot fault and parallel bars. The volume of brain infarction was analyzed in brain sections stained with 2,3,5 triphenyltetrazolium chloride solution (2%), at 37° C, for 30 min. Brain slices stained with Nissl method was used to quantify neurons, while astrocytes were quantified in brain sections by using immunohytochemistry to glial fibrillary acidic protein (GFAP). The results showed that animals exercised before and after cerebral ischemia exhibited better motor performance in functional tests and lower volume of cerebral infarction as compared to those not exercised. Animals exercised before cerebral ischemia had lower cerebral infarct volume and greater density of neurons in the striatum, in the apex of the dentate gyrus of the hippocampus and in the motor cortex contralateral to the lesion, and showed more reactive astrocytes in the motor cortex of both hemispheres than animals not exercised. The density of neurons of the brain regions analyzed remained unchanged in animals exercised after cerebral ischemia. These results indicate that exercise training promotes benefits to motor performance and neuroplasticity in the brain of rats subjected to cerebral ischemia.