Author(s): YANAGITA, S., NATSUKO, K., Institution: TOKYO UNIVERSITY OF SCIENCE, Country: JAPAN, Abstract-ID: 1774

INTRODUCTION:
In recent years, the importance of health promotion through increased physical activity, which includes not only exercise but also other lifestyle activities, has become prevalent. Animal experiments are required to analyze the mechanisms of the effects of exercise on physical and mental functions, and studies have been conducted using treadmills and running wheels. On the other hand, there are only a few animal models to examine the increase in physical activity during daily living activities.
Numerous studies have shown that enriched environments (EE) could be effective for experimental rodents to improve some brain functions related to stress response and anxiolytic effect, and speculating that increasing levels of physical activity and/or playing factor could have beneficial effects. We aimed to brush up the EE and further develop an environment specialized for increasing physical activity.
METHODS:
We made a multistory enriched environment (Multi-EE) that can increase physical activity in rats. In this study, we examined whether the amount of daily physical activity increases when the enriched environment is multileveled. We also aimed to examine whether the biological effects of this increase in physical activity were different from wheel running. We originally made Multi-EE, which are consisted of three stories. The male Wistar rats housed the Multi-EE or normal- EE for 4weeks in group housing conditions (2 rats per cage). The rats housed in Multi-EE allow access to the three stories freely by ladders. Daily physical activity was recorded using a mobile accelerometer and compared Multi-EE and Normal-EE. Following 4weeks, brain monoamine levels, which are involved with increasing physical activity-induced- psychological effects, were measured by High-Performance Liquid Chromatography (HPLC) in several brain regions. Muscle and fat volume were also measured. In this study, we have been successful to analyze voluntary physical activity in both normal-EE and Multi-EE.
RESULTS:
The results showed that Multi-EE showed a different transition in physical activity than normal-EE, and an increase in vertical living space did not contribute to an increase in physical activity. On the other hand, the voluntary physical activity in Multi-EE significantly increased the volume of soleus muscle compared to normal-EE, indicating that Multi-EE might be effective to increase the physical load. However, the Multi-EE housing was not able to change the brain monoamine levels, which are known to be increased by running wheel. The changing levels of these monoamines are known to have some beneficial effects on brain health.
CONCLUSION:
Therefore, the results of the present study suggest that increasing levels of physical activity by Multi-EE have a different physiological effect compared to running wheel. Investigating the relationship between increased physical activity and horizontal space expansion may lead to the development of new animal experimental models.