Sophoridine from Sophora Flower Attenuates Ovariectomy Induced Osteoporosis through the RANKL-ERK-NFAT Pathway

An imbalance in osteogenesis and osteoclastogenesis is a crucial pathological factor in the development of osteoporosis. Osteoclasts (OCs) play a pivotal role in osteoporosis, whose new therapy exploration has been focused on the suppression of OC formation. Sophoridine is found from the Chinese traditional food sophora flower to exhibit anti-osteoporosis capacity by screening. This study is focused on its anti-osteoporosis mechanism evaluation. The anti-osteoporosis effect of sophoridine, (15 mg kg–1 body), was evaluated in ovariectomized (OVX) mice by monitoring changes in bone histomorphometry index, formation of osteoclasts from blood-derived mononuclear cells, and changes in the synthesis of pro-osteoclastogenic cytokines. Signal pathways were investigated by QPCR, Western blot, and immunofluorescence. Sophoridine has a significant anti-osteoporosis effect in vivo, which can inhibit RANKL-induced OC formation, the appearance of OC-specific marker genes, and OC marker protein in vitro. Mechanistically, sophoridine dose- and time-dependently blocks the RANKL-induced OC formation and the activation of ERK and c-Fos as well as the induction and nucleus translocation of NFATc1. Sophora flower might be a useful alternative functional food in preventing or treating osteoporosis.