OBJECTIVE:To investigate the effect of acupuncture at acupoint of Shenshu (BL 23) in ovariectomized rats and sham-operated rats.METHODS:Female Sprague-Dawley rats were divided into the following four groups (n =12 each):sham operation only (Sham),sham operation with acupuncture (Sham + ACP),ovariectomy only (OVX),and ovariectomy with acupuncture (OVX + ACP).Operations were performed at the 9th week of age.Acupuncture of Shenshu (BL 23) was started at the 1 1th week of age and conducted 3 times per week until the 26th week of age.RESULTS:Among ovariectomized rats,the acupuncture-treated rats had significantly lower body weights and cross-linked N-telopeptide of type 1 collagen levels in the urine after 3 weeks of acupuncture treatment,higher bone mineral density of the lumbar vertebra after 7 weeks,and smaller trabecular separation of the sixth lumbar vertebra,measured by micro-computed tomography,after 17 weeks than control rats.These effects were not observed in sham-operated rats.Blood concentrations of estradiol were significantly higher in the OVX + ACP group than in the untreated group.Acupuncture treatment increased plasma testosterone levels in sham-operated rats,while this increase was not observed in OVX rats.CONCLUSION:Acupuncture of Shenshu (BL 23) prevents bone loss and structural changes by suppressing bone resorption.