Stimulus in the form of rotation and shaking of a platform and its effect on the formation of trabecular bone in the lumbar vertebrae of mice

摘要

Background and aims: Elderly individuals who suffer a fracture develop a gait disturbance and require prolonged bedrest. A fracture has a massive impact both physically and mentally and markedly diminishes quality of life. A new form of therapeutic exercise that mitigates the abrupt decrease in bone density in postmenopausal women must soon be developed so that those problems can be avoided. Methods: The current study used a model of the decrease in bone density in ovariectomized mice to simulate post-menopausal women. The stimulus was provided by a shaking horizontal platform rotating in a circular motion. Results: Comparison of the +/+ (ovariectomized/stimu-lated) group and +/- group indicated a significant decrease in BV/TV (p<0.01), Tb.Th (p<0.01), and Tb.N (p<0.05) in the +/+ group and a significant increase in OV/BV (p<0.01), OV/OS (p<0.01), BFR/ BV (p<0.01), dLS/BS (p<0.05), MS/BS (p<0.05), BRs.R (p<0.01), and Tb.Sp (p<0.01) in the +/+ group. Physical therapy to prevent a decrease in bone density was studied via stimulus in the form of rotation of a platform. Analysis of bone histomorphometry revealed lessening of the decrease in bone density of the lumbar vertebrae, a feat that the stimulus from conventional physical therapy had failed to achieve. Conclusion: The current study delivered a shaking stimulus to mice in a model of postmenopause. Analysis of bone histomorphometry of the lumbar vertebrae suggested lessening of the abrupt decrease in bone density of trabecular bone. If this finding is used clinically, it could lead to physical therapy exercise that would be able to prevent compression fractures of the lumbar vertebrae.