Effects of inducing exercise on growing mice by means of three-dimensional structure in rearing environment.
We reared ICR mice during a growth period (3 to 10 weeks of age) and examined the effect of exercise induction, by enriching the rearing environment with obstacles such as ladders, compared to the standard environment. Environmental enrichment significantly increased the amount of exercise in both sexes (P<0.01). Enriched exercise mice had higher body weight than control mice at 6 to 9 weeks of age in males and 8 weeks of age in females (P<0.05). The sexual maturation of female enriched exercise mice was significantly advanced compared to the control (P<0.001). Enriched exercise mice showed decreased anxiety-like behavior in the open field test and lower plasma corticosterone levels in both sexes compared to the control, and differences were statistically significant in males (P<0.05). In both sexes, enriched exercise appeared to increase natural killer cells in blood compared to the control, but no statistical differences was detected. In conclusion, we confirmed that daily low-stress exercise could be induced using a three-dimensional rearing environment in growing mice. In addition, we suggest that exercise has beneficial effects on physical growth, sexual maturation and anxiety-like behavior. Furthermore, environmental enrichment might be more effective in male than female in group-housed mice.
Field Science Center, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.
Yu
Y
Nakamura
Aki
A
Ueno
Yuka
Y
Nunomura
Kazuhide
K
Nakagaki
Shohei
S
Takeda
Kaoru
K
Suzuki
D000818:Animals; D001007:Anxiety; D003345:Corticosterone / Q000097:blood; D005260:Female; D006799:Housing, Animal; D007694:Killer Cells, Natural / Q000378:metabolism; D008297:Male; D051379:Mice / Q000254:growth & development / Q000502:physiology*; D008813:Mice, Inbred ICR; D010805:Physical Conditioning, Animal; D012741:Sexual Maturation; D015430:Weight Gain
D003345:Corticosterone