Whole body vibration at low-frequency can increase trabecular thickness and width in adult rats

OBJECTIVE: This study aimed to examine whether WBV becomes a possible modality for the primary prevention of osteoporosis by exploring WBV frequency that has positive effects on bone properties in adult rats. METHODS: Thirty-six 24-week-old rats were divided into one control and 5 experimental groups, which underwent WBV at various frequencies (15, 30, 45, 60 or 90 Hz), with a magnitude of 0.5 g, for 15 min/day, 5 days/week, for 8 weeks. Bone size, muscle weight and bone mechanical strength were measured at the end of experimental period. Bone mass, trabecular bone microarchitecture (TBMA) and cortical bone geometry were analyzed by micro-CT. Circulating bone formation/resorption markers were determined by ELISA. RESULTS: Body weight-corrected soleus weight in all experimental groups and body weight-corrected extensor digitorum longus muscle weight in the 15 and 30 Hz groups were significantly higher than those of the control group, respectively. Femur trabecular thickness and width were significantly higher in the 15 Hz group than in the control group. However, there was no difference in bone mechanical strength or bone formation/resorption markers among all groups. CONCLUSION: These results suggest that WBV at low-frequencies may become a potent modality for the primary prevention of osteoporosis in adults.