Original Research ARTICLE
Environmental impoverishment, aging and reduction in mastication affect mouse innate repertoire to explore novel environments and to assess risk
- 1Centro Universitário do Estado do Pará, Brazil
- 2Universidade Federal do Pará, Brazil
We examined in an open arena, the exploratory and locomotor activities of mature (6-month-old; 6M), late mature (12-month-old; 12M), and aged (18-month-old; 18M) mice, subjected to distinct masticatory regimens and environments. Three different regimens of masticatory activity were used: continuous normal mastication with hard pellets - HD; normal mastication followed by reduced mastication with equal periods of pellets followed by soft powder - HD/SD; or rehabilitated masticatory activity with equal periods of hard pellets, followed by powder, followed by pellets - HD/SD/HD). Under each diet regimen, half of the individuals were raised in standard cages (impoverished environment; IE) and the other half in enriched cages (enriched environment; EE). Animals behavior on the open field (OF) task were recorded by webcam and analyzed with Any Maze software (Stoelting). Independent of diet regime, 6M young mice maintained in an enriched environment where voluntary exercise apparatus is available, revealed significant less body weight than all other groups. Although body weight differences were minimized as age progressed, 18M EE group revealed intragroup significant influence of diet regimens. The locomotor and exploratory activities in OF task declined with age, and this was particularly evident in 18M HD EE mice. Although all groups kept their preference by the peripheral zone, the outcomes were significantly influenced by interactions between environment, age, and diet. We suggest that long life environmental enrichment reduces the tendency to avoid open/lit spaces (OF) and this is particularly influenced by masticatory activity. These measurements may be useful in discussions of anxiety-related tasks.
Keywords: Reduced mastication, environmental changes, Locomotor and Exploratory activities, anxiety-like behavior, Aging
Received: 13 Jul 2018;
Accepted: 29 Jan 2019.
Edited by:Rubem C. Guedes, Federal University of Pernambuco, Brazil
Reviewed by:Nafisa M. Jadavji, Ottawa Hospital Research Institute (OHRI), Canada
Marcelo C. Silva, Federal University of São Paulo, Brazil
Copyright: © 2019 Mendes, Paixão, Picanço Diniz and Sosthenes. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Cristovam W. Picanço Diniz, Universidade Federal do Pará, Belém, 66075-110, Pará, Brazil, firstname.lastname@example.org