Skeletal effects of whole-body vibration in adult and aged mice

Low-amplitude, whole-body vibration (WBV) may be anabolic for bone. Animal studies of WBV have not evaluated skeletal effects in aged animals.Weexposed 75 male BALB/c mice (7 month/young-adult; 22 month/aged) to 5 weeks of dailyWBV(15 min/day, 5 day/ wk; 90 Hz sine wave) at acceleration amplitudes of 0 (sham), 0.3, or 1.0 g. Whole-body bone mineral content (BMC) increased with time in 7 month ( p<0.001) but not 22 month ( p = 0.34) mice, independent ofWBV( p = 0.60). In 7 month mice, lower-legBMCincreased with time in 0.3 and 1.0 g groups (p < 0.05). but not in the sham group ( p = 0.09), indicating a positive WBV effect. In 22 month mice, there were no changes with time in lower-leg BMC ( p = 0.11). WBV did not affect tibial trabecular or cortical bone structure (by μCT), dynamic indices of trabecular or cortical bone formation, trabecular osteoclast surface, or the mass of the reproductive fat pad ( p>0.05). Each of these outcomes was diminished in 7 month versus 22 month animals ( p<0.05). In summary, 5 weeks of daily exposure to low-amplitudeWBVhad no skeletal effects in aged male mice. The potential of WBV to enhance bone mass in age-related osteoporosis is not supported in this preclinical study.