Physical exercise increases GFAP expression and induces morphological changes in hippocampal astrocytes

Abstract

Physical exercise has an important influence on brain plasticity, which affects the neuron-glia interaction. Astrocytes are susceptible to plasticity, and induce and stabilize synapses, regulate the concentration of various molecules, and support neuronal energy metabolism. The aim of our study was to investigate whether physical exercise is capable of altering the morphology, density and expression of glial fibrillary acidic protein (GFAP) in astrocytes from the CA1 region of rat hippocampus. Thirteen male rats were divided in two groups: sedentary (n = 6) and exercise (n = 7). The animals in the exercise group were submitted to a protocol of daily physical exercise on a treadmill for four consecutive weeks. GFAP immunoreactivity was evaluated using optical densitometry and the morphological analyses were an adaptation of Sholl's concentric circles method. Our results show that physical exercise is capable of increasing the density of GFAP-positive astrocytes as well as the regional and cellular GFAP expression. In addition, physical exercise altered astrocytic morphology as shown by the increase observed in the degree of ramification in the lateral quadrants and in the length of the longest astrocytic processes in the central quadrants. Our data demonstrate important changes in astrocytes promoted by physical exercise, supporting the idea that these cells are involved in regulating neural activity and plasticity.

Astrocyte morphology after ischemic and hemorrhagic experimental stroke has no influence on the different recovery patterns

“…This finding was correlated with functional forelimb recovery [6]. Moreover, enriched environment [8] and physical exercise [7] induce changes in the polarization of GFAP-positive astrocytes in healthy animals. Therefore, it is possible that astrocyte morphology might be linked to differential recovery patterns between ischemic and hemorrhagic stroke.…”

“…10.005 0166-4328/© 2014 Elsevier B.V. All rights reserved. exercise and environmental enrichment [7,8]. For example, skilled reaching training after collagenase-induced intracerebral hemorrhage increases the length of primary astrocytic GFAP-positive processes in perilesional tissue.…”

“…Briefly, brain sections were post-fixed in 4% PF for 15 min. After three washes in cold phosphate buffered saline (PBS, pH 7.4), GFAP immunohistochemistry was performed as previously described [7]. Sections were blocked for endogenous peroxidases (3% hydrogen peroxide in PBS) for 30 min, washed in PBS containing 0.4% Triton X-100 (PBS-Tx) and blocked with 2% bovine serum albumin (BSA) in PBS-Tx for 30 min.…”

“…The astrocytes located inside this square or intersected by the upper and/or right edges of the square were counted. Astrocytes intersected by the lower and/or left edges of the square were not counted [7,8].…”

New advances on glial activation in health and disease

“…Morphological changes in astrocytes have been documented in chronic stress [76] , traumatic brain injury [77] , neurodegenerative disease [78] , CNS viral and bacterial infections [79,80] , and behavioral and mood disorders [81,82] . Experimentally, changes in astrocyte morphology have been reported after ethanol administration [83] , dietary-induced obesity [84] , and physical exercise [85] . These structural changes can be detected not only at the level of their cell body and proximal processes, but more importantly, through their fine, lamellate distal processes that surround synapses and ensheath axonal nodes [86] .…”