Changes in Histomorphometric and Mechanical Properties of Femurs Induced by Acupuncture at the Shenshu Point in the SAMP6 Mouse Model of Senile Osteoporosis

<i>Background/Objective:</i> The effect of acupuncture on the changes in the histomorphometric and mechanical properties of femurs in senescence-accelerated mice strain P6 (SAMP6) was evaluated in this work. <i>Methods:</i> Six-month-old male SAMP6 and SAMR1 mice were allocated to 1 of 4 groups: SAMP6 control group (Pc), SAMP6 non-acupoint control group (Pn), SAMP6 acupuncture group (Pa) and SAMR1 control group (Rc). The Pa group was acupunctured at the Shenshu point (BL23) once daily for 8 weeks. Two non-acupoints at the hypochondria were needled for the Pn group. Mice in the other 2 groups were grasped using the same method as for the Pa group. The serum testosterone and osteocalcin (OC) levels were determined by radioimmunoassay. The histomorphometric data were obtained from undecalcified specimens, and the mechanical properties of the femur were assessed by the 3-point bending test. <i>Results:</i> After acupuncture treatment, the decreased serum testosterone level in SAMP6 mice increased markedly, whereas the increased OC concentration declined sharply. The bone histomorphometric and mechanical indexes of SAMP6 mice also improved significantly. The values of trabecular thickness, trabecular bone volume, osteoid volume, mineral apposition rate and bone formation rate in Pa mice increased by 20.4, 18.1, 14.1, 9.9 and 14.7%, respectively, compared with Pc mice. The scores for ultimate force, yield force, elastic stress, ultimate stress and energy to yield force for Pa mice were significantly higher than those of Pc and Pn mice. <i>Conclusion:</i> Therefore, acupuncture at <i>BL23</i> was effective in promoting bone formation, restoring the amount of bone volume, improving bone architecture and reversing osteoporosis in SAMP6 mice to some degree by enhancing the secretion of testosterone and declining bone turnover.