Effect of Exercise Prior or After Ischemia on the Density of Neurons and Astrocytes in the Brain of Rats

Abstract

The aim of this study was to analyse the density of astrocytes and neurons in the motor areas of the cortex, striatum and hippocampus of rats that performed exercise before or after cerebral ischemia. A total of 36 Wistar rats were separated into two groups: One that was subjected to Middle Cerebral Artery Occlusion (MCAO) and the other that underwent surgical access in the absence of ischemia. Both groups were subdivided into: Animals that underwent exercise prior to MCAO and sham surgery (AI and AC, n = 12); animals that underwent exercise after MCAO and sham surgery (DI and DC, n = 12); and animals that did not undergo exercise (SI and SC, n = 12). The brains of mice were sectioned and stained by the Nissl method for staining of neurons and the astrocytes were labeled by immunohistochemistry with glial fibrillary acidic protein. Physical training was conducted after the surgery for 6 weeks (30 min/day), 5 days per week. The animals exercised before cerebral ischemia showed greater density of neurons in the striatum, in the apex of the dentate gyrus of the hippocampus, in the motor cortex contra lateral to the lesion and more astrocytes in the motor cortex of the cerebral hemispheres compared with the untrained group (p<0.05). The density of neurons in the brain regions analysed remained unchanged in exercised animals from the fourth day after cerebral ischemia when compared with the sedentary group.