Increased physical activity is not enough to recover astrocytic population from dark-rearing. Synergy with multisensory enrichment is required

Abstract

Elimination of sensory inputs (deprivation) modifies the properties of the sensory cortex and serves as a model for studying plasticity during postnatal development. Many studies on the effects of deprivation have been performed in the visual cortex using dark-rearing as a visual deprivation model. It induces changes in all cellular and molecular components, including astrocytes, which play an important role in the development, maintenance, and plasticity of the cortex, mediated by cytokines which have been termed angioglioneurins. When one sense is deprived, a compensatory mechanism called cross-modal plasticity increases performance in the remaining senses. Environmental enrichment is so far the best-known method to compensate sensorial deprivation. The aim of this work is to study the effects of exercise alone, and of an enriched environment combined with exercise, on astroglial population in order to observe the effects of exercise by itself, or the potential synergistic effect during the rat visual system development. Pregnant Sprague-Dawley rats were raised in one of the following rearing conditions: in total darkness and enriched environment conditions with physical exercise, and in total darkness with voluntary physical exercise. Astrocytic density was estimated by immunohistochemistry for S-100β protein and quantifications were performed in layer IV. The somatosensorial cortex barrel field was also studied as control. Our main result shows that an enriched environment combined with voluntary physical exercise manages to reverse the negative effects induced by darkness over the astroglial population of both the visual and the somatosensory cortices. On the other hand, exercise alone only produces effects upon the astroglial population of the somatosensory cortex, and less so when combined with an enriched environment.

Blindness and Human Brain Plasticity

“…The effect of environment can be dramatic; for example, dark-reared animals in standard cages show a striking reduction in the number of astrocytes compared to controls. In contrast, dark-reared animals in enriched cages have more astrocytes than control animals (Bengoetxea et al 2013). These results suggest that even the basic neuroanatomical consequences of dark rearing can be very different when animals must learn to solve tasks like navigation and food finding using their remaining senses.…”

Voluntary Exercise Induces Astrocytic Structural Plasticity in the Globus Pallidus

“…The beneficial effect of physical exercise may, in part, be attributed to upregulated neurotrophins, which would help to protect neural functions (Hillman et al, 2008 ). In addition to these effects on neurons, recent studies have demonstrated that physical exercise induces structural and biochemical changes in astrocytes as well as in neurons (de Senna et al, 2011 ; Bengoetxea et al, 2013 ). These studies suggested that the Olig2-lineage astrocytes in the GP can be a good model to delineate the relationship between neuronal activities and astrocytic morphologies.…”

High-Altitude Cognitive Impairment Is Prevented by Enriched Environment Including Exercise via VEGF Signaling

“…At P48, half of the rats were kept in Zürich (low-altitude group), and the other half transported to the Jungfraujoch High Altitude Research Station on the Jungfraujoch (JFJ, 3450 m asl), (high-altitude group) in a single journey of 250 min duration. Both low- and high-altitude groups were then housed at 22°C room temperature with a 12 h light/dark cycle and access to food and water ad libitum , either in standard laboratory conditions (SC) or in an enriched environment that included voluntary exercise (EE) (Bengoetxea et al, 2013), and received either sucrose, (EE + veh), or the tyrosine kinase inhibitor Vandetanib (EE + inh).…”