MECHANICAL STIMULATION IN THE FORM OF VIBRATION PREVENTS POSTMENOPAUSAL BONE LOSS IN OVARIECTOMIZED RATS

Physical exercise is recommended for the prevention and treatment of o steoporosis. However, its exact role and effectiveness in adulthood is unclear. While vigorous exercise of long duration enhances bone densi ty, few adult individuals comply with such training programs. The pres ent study evaluates the influence of nonphysiological mechanical stimu lation, in the form of low intensity vibration (frequency: 50 Hz, acce leration: 2 g, 30 min/day for 5 days/week), on the prevention of bone loss in an animal model of postmenopausal osteoporosis. In the ovariec tomised groups of rats a statistically significant (p < 0.05) decrease of bone density (femur and tibia) was recorded at 5 weeks postovariec tomy. This effect was maintained for the 12 week duration of the study . Vibration prevented early bone loss after ovariectomy. Vibrated ovar iectomised rats showed statistically significantly higher (p < 0.05) B MD values compared to those of their ovariectomised controls at 5 week s. Vibration did not influence the bone density of the SHAM-operated r ats. Although vibration increased ultimate strength (fracture load of the rat femur) in the ovariectomised rats, this finding was not statis tically significant. Our data indicate that this method of safe and ea sily applicable vibration, in the form of a vibrating platform, is eff ective in preventing early postovariectomy bone loss in an animal mode l.