Funabashi Daisuke, Tsuchida Ryuki, Matsui Takashi, Kita Ichiro, Nishijima Takeshi
Department of Health Promotion Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan.
Exercise Biochemistry & Sport Neurobiology Division, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
Front Sports Act Living. 2023 Sep 26;5:1203260. doi: 10.3389/fspor.2023.1203260. eCollection 2023.
Environmental enrichment (EE) improves various health outcomes, such as hippocampal neurogenesis, in rodents, which is thought to be caused, in part, by increased physical activity. However, the specific effect of each enrichment component, such as enlarged housing spaces and increased spatial complexity with a variety of objects, on physical activity remains unclear because of methodological limitations in measuring physical activity. We aimed to examine whether enlarged housing spaces and increased spatial complexity increase physical activity in mice using a body-implantable actimeter.
Adult male C57BL/6J mice were assigned to either standard housing or EE groups. The housing environment in the EE mice was gradually enriched by enlarging the housing space and the placement of a variety of objects. Physical activity was measured using a body-implanted actimeter. Hippocampal neurogenesis was immunohistochemically examined.
Enlarged housing spaces and the placement of a variety of objects did not increase physical activity in mice. In contrast, hippocampal neurogenesis was enhanced in the EE mice, suggesting that environmental interventions successfully provided enriched housing conditions for these mice.
These results indicate that enlarged housing spaces and increased spatial complexity do not increase physical activity in mice. Furthermore, we found that EE enhanced hippocampal neurogenesis without increasing activity volume. Besides the current understanding that increasing the amount of physical activity is key to improving hippocampal function, our result suggests that the environment in which physical activity takes place is also a crucial contextual factor in determining the impact of physical activity on hippocampal function.
环境富集（EE）可改善啮齿动物的多种健康指标，如海马神经发生，这被认为部分是由体力活动增加所致。然而，由于测量体力活动的方法存在局限性，每种富集成分（如扩大的居住空间和通过各种物体增加空间复杂性）对体力活动的具体影响仍不清楚。我们旨在使用可植入式活动计来研究扩大的居住空间和增加的空间复杂性是否会增加小鼠的体力活动。
将成年雄性C57BL/6J小鼠分为标准饲养组或EE组。通过扩大居住空间和放置各种物体，逐步丰富EE小鼠的居住环境。使用植入式活动计测量体力活动。通过免疫组织化学方法检测海马神经发生。
扩大的居住空间和放置各种物体并未增加小鼠的体力活动。相反，EE小鼠的海马神经发生增强，这表明环境干预成功地为这些小鼠提供了丰富的居住条件。
这些结果表明，扩大的居住空间和增加的空间复杂性不会增加小鼠的体力活动。此外，我们发现EE增强了海马神经发生，而没有增加活动量。除了目前认为增加体力活动量是改善海马功能的关键这一认识外，我们的结果还表明，进行体力活动的环境也是决定体力活动对海马功能影响的关键背景因素。
