Voluntary exercise is a moderately effective mitigator of chronic social isolation stress in two female rodent models

Abstract

Depression is a common mood disorders, particularly among women, and often with social stress precursors. Exercise, in addition to the known physical benefits, can have psychological benefits, potentially alleviating certain symptoms of stressors. This study investigated the impact of chronic social isolation stress in two female rodent models – mice and prairie voles. To assess the mitigating impact of exercise, paired and isolated animals were either provided 24-hour access to running wheels in their cages or remained sedentary. In mice, only animals that remained paired and had access to exercise wheels retained adaptive levels of active behaviors in the forced-swim test. However, either remaining paired or having access to a running wheel prevented increased corticosterone levels in mice. By contrast, in voles, either being paired or having access to a running wheel promoted adaptive levels of active behaviors in the forced-swim test. Similar to mice, either being paired or having access to a running wheel also prevented increased corticosterone levels in prairie voles. Body weight and adrenal:body mass ratios were not affected by either isolation or exercise in either species. Together these findings highlight the important differences between female rodents of different species in responses to chronic social stress. They also allude to differences between female and male rodent models. Lastly, these results indicate that for female rodents, exercise can provide certain mitigating effects against chronic social stress consequences.