BACKGROUND:FoxO1 participates in diverse processes of cellphysiology, including cellproliferation and apoptosis, reactive oxygen species, longevity, cancer, the regulation of cellcycle and metabolism. Vibration loading is believed to promote metabolism, delay muscle fatigue, and facilitate adaptive bone reconstruction. OBJECTIVE:To investigate the effects of whole-body vertical vibration on the protein expression of FoxO1 in tibia and bone marrow cellof ovariectomized (OVX) osteoporosis rats.
METHODS:Thirty-six healthy 3-month-old female Sprague-Dawley rats were randomly divided into the fol owing three groups by body weight:sham-operation (sham) group, OVX group, and OVX whole-body vertical vibration (OVX+V) group. At the 11th week after operation, the OVX+V group rats were vibrated on a vibration platform twice per day for 7 weeks according to the fol owing schedule:whole-body vertical vibration for 15 minutes, with an interval of 10 minutes. The frequency was 90 Hz and the amplitude was 0.5 mm. Within 24-48 hours after the last treatment, the fifth lumbar vertebra as wel as the right femur and tibia were isolated. The bone mineral density of the fifth lumbar vertebra and right femur was detected by dual-energyΧ-ray absorptiometry. The FoxO1 protein expression in proximal tibia and bone marrow cells was detected by western blot assay.
RESULTS AND CONCLUSION:As revealed by the results of bone mineral density, the bone mineral densities of the proximal and distal femur as wel as the fifth lumbar vertebra in OVX+V group were significantly increased while no significant difference could be seen in the mid shaft. As revealed by the results of western blot, there was no FoxO1 protein expression in the tibia, but it could be detected in the bone marrow cells. Compared with the sham group, there was no significant difference in FoxO1 protein expression in bone marrow cells of OVX group;compared with the OVX group, the protein expression level of FoxO1 in bone marrow cells of the OVX+V group was significantly reduced. The results suggested that whole-body vertical vibration could inhibit the protein expression of FoxO1 in bone marrow cells of osteoporosis rats.