Environmental impoverishment and aging alter object recognition, spatial learning, and dentate gyrus astrocytes

Universidade Federal do Pará-UFPA, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Brazil.
European Journal of Neuroscience (Impact Factor: 3.18). 08/2010; 32(3):509-19. DOI: 10.1111/j.1460-9568.2010.07296.x
Source: PubMed


Environmental and age-related effects on learning and memory were analysed and compared with changes observed in astrocyte laminar distribution in the dentate gyrus. Aged (20 months) and young (6 months) adult female albino Swiss mice were housed from weaning either in impoverished conditions or in enriched conditions, and tested for episodic-like and water maze spatial memories. After these behavioral tests, brain hippocampal sections were immunolabeled for glial fibrillary acid protein to identify astrocytes. The effects of environmental enrichment on episodic-like memory were not dependent on age, and may protect water maze spatial learning and memory from declines induced by aging or impoverished environment. In the dentate gyrus, the number of astrocytes increased with both aging and enriched environment in the molecular layer, increased only with aging in the polymorphic layer, and was unchanged in the granular layer. We suggest that long-term experience-induced glial plasticity by enriched environment may represent at least part of the circuitry groundwork for improvements in behavioral performance in the aged mice brain.

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Available from: Daniel Guerreiro Diniz
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    • "However, structural studies on astrocytes have revealed a significant accumulation of lipofuscin in cytoplasm with aging (reviewed in Casoli et al., 2013; Rodríguez-Arellano et al., 2015). In aged animals, the increased amount of glial fibrillary acidic protein (GFAP) and vimentin filaments, represent the most common change observed in astrocytes (Diniz et al., 2010). Moreover, astrocytes undergo changes that indicate the presence of SASP (Salminen et al., 2011). "
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    • "We used the following classification: impoverished condition, social condition, and enriched condition [112]. Impoverished animals are individually housed in standard cages, animals in social conditions are housed in groups, and animals in enriched conditions are housed in cages that stimulate an animal's exploratory and motor behaviour by providing them with access to toys, ladders, tunnels, running wheels, ropes, and bridges that are changed periodically [113]. In this condition, animals are usually kept in groups so the enrichment is therefore both social and physical. "
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    • "Environmental enrichment has been defined as a combination of complex physical activity and social stimulation, reproduced in animal cages with running wheels, ropes, bridges, tunnels, and toys that are changed periodically.15,16 We demonstrated that mice maintained in enriched environments generally performed well on the spatial memory tasks on the Morris water maze and perfectly distinguished between old and recent and between displaced and stationary objects in the episodic-like memory tests, whereas individual mice maintained in impoverished cages lost those abilities.14 Morris water maze and episodic-like memory tasks have been previously detailed.17,18 "
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