OVX-induced osteoporosis mouse model

Twenty-four 8-weeks old female C57BL/6 mice were provided by the CAVENS Laboratory Animal (Changzhou, china). The mice were grouped randomly into 3 groups (n = 6/group): the sham that received PBS injection (Sham group), OVX that received PBS injection (OVX group), OVX with 10 mg/kg (+)-ND injection. According to standard procedures, the mice in OVX + ( + )-ND group and OVX group were intraperitoneally injected with 3% chloral hydrate under anaesthesia and underwent bilateral ovariectomy to remove ovaries. The mice in sham group received surgery but ovaries were not removed. One week for postoperative recovery after surgery, we subcutaneously injected the mice with PBS (Sham and OVX groups) or with (+)-ND (10 mg/kg) every 2 d. After 6 weeks, we euthanized all the mice, and all the femurs were collected, fixed by 4% PFA, and prepared for the micro-CT and histologic evaluations.