Aim To investigate the preventive effects of misoprostol on osteoporosis in aged ovariectomized(OVX)rats.Methods Female,10-month-old SD rats were ovariectomized(OVX)and,2 months later,were treated with misoprostol or controls for 2 months.The static and dynamic parameters in trabecular bone of the forth lumbar vertebrae(LV4)were examined with histomorphometrical analyses;the fifth lumbar vertebrae(LV5)was used to perform the compression test.Results Compared with the data from the sham-operated rats,the percent trabecular area and elastic modulus significantly decreased in OVX rats.Correspondingly,the bone break load and break stress decreased of post OVX was compared with those of sham-operated rats.Misoprostol increased the percent trabecular area by 21.6% compared with OVX rats,but it couldn't meet the statistical significance.Misoprostol enhanced the break load and elastic modulus compared with OVX rats.Conclusion Misoprostol can improve biomechanics of bone in ovariectomized osteoporosis rats.