Abstract
Anemarrhena asphodeloides Bunge has been traditionally used in Korean medicine for its antipyretic, diuretic, sedative, and antitussive effects. In the present study, the effects of an ethanol extract of A. asphodeloides Bunge (AAB) on osteoporosis and its underlying mechanisms on bone remodeling were investigated. Osteoporosis was induced in ICR strain mice by ovariectomy. The mice were divided into four groups: sham, ovariectomized, 17β‑estradiol and 100 mg/kg AAB. The treatment was continued for 4 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using dual‑energy X‑ray absorptiometry. In addition, Raw 264.7 cells were treated in the presence of 0.1, 1 and 10 µg/ml AAB with 100 ng/ml receptor activator of nuclear factor κΒ ligand (RANKL) to induce osteoclast formation and stained with tartrate resistant acid phosphatase. In addition, levels of osteoclast‑related factors were analyzed to investigate the signaling cascades in osteoclasts. The results demonstrated that AAB treatment reversed the decreases of both BMD and BMC in osteoporotic femurs. Additionally, the formation of osteoclasts was significantly suppressed by the AAB treatment in RANKL‑stimulated Raw 264.7 cells. Compared with cells treated with RANKL alone, the AAB‑treated osteoclasts had significantly decreased tumor necrosis factor‑α and interleukin‑6. The protein levels of c‑fos were also decreased in the AAB‑treated osteoclasts. Furthermore, the RANKL‑induced nuclear translocation of nuclear factor‑κB was attenuated in osteoclasts by the AAB treatment compared with cells treated with RANKL alone. Finally, AAB treatment downregulated the phosphorylation of mitogen‑activated protein kinases. The present results demonstrated that AAB exhibited ameliorative effects on osteoporosis by inhibiting osteoclastogenesis, and suggested that AAB may be a potential candidate for the treatment of osteoporosis.