Effect of the Physical Activity on Bone in Ovariectomized Mice

Abstract

The effects of physical activity, treadmill running, on bone of ovariectomized mice were investigated. Forty 12-week-old female ICR mice were used. They were ovariectomized (OVX) or sham-operated (SHAM) and half of them were run on a treadmill at 16 m/min, 5 days/week for 6 weeks (Ex). All animals were sacrificed at week 12 after operation. Mechanical strength of the left femur and tibia were measured by the three-point bending strength test. The bones were dried, weighed and burned to ash. Mechanical strength and ash content of the femur and tibia in Ex group were significantly higher than those of control animals. Also mechanical strength of femur and tibia in OVX/Ex were not different from SHAM/Cont mice. Physical activity, treadmill running, thus affected inhibition of bone loss and maintenance of bone mass. It is necessary to continue this basic study to determine effective modes of physical activity.