Skeletal effects of low-intensity pulsed ultrasound on the ovariectomized rodent

Growing evidence supports low-intensity pulsed ultrasound (US) as an osteog enic mechanical stimulus. Its effects on isolated bone cells and on fractur ed bone are established. However, its effects on osteoporosis are not clear . This study examined US effects on ovariectomy (OVX) induced bone changes within the rodent hindlimb (distal femur and proximal tibia), and on normal bone in animals following sham-OVX. Animals were exposed to daily unilater al active-US and contralateral inactive-US for 12 weeks. Bone status was as sessed using dual energy X-ray absorptiometry and histomorphometry. Ovariec tomy resulted in significant bone changes. Low-intensity pulsed US did not influence these changes. These results suggest that the US dose introduced may not be a beneficial treatment for osteoporosis, and that intact bone ma y be less sensitive to US than fractured bone and isolated bone cells. This may relate to the biophysical mechanisms of action of US, US-bone interact ions and tissue level processes taking place.