Abstract
In this study, we investigated the mechanisms by which puerarin alleviates osteoclast-related loss of bone mass in ovariectomy (OVX)-induced osteoporosis model mice. Puerarin-treated OVX mice exhibited higher bone density, fewer tartrate-resistant acid phosphatase (TRAcP)-positive osteoclasts, and levels of lower reactive oxygen species (ROS) within bone tissues than vehicle-treated OVX mice. Puerarin suppressed in vitro osteoclast differentiation, hydroxyapatite resorption activity, and expression of osteoclastogenesis-related genes, such as NFATc1, MMP9, CTSK, Acp5 and c-Fos, in RANKL-induced bone marrow macrophages (BMMs) and RAW264.7 cells. It also reduced intracellular ROS levels by suppressing expression of TRAF6 and NADPH oxidase 1 (NOX1) and increasing expression of antioxidant enzymes such as heme oxygenase-1 (HO-1). Puerarin inhibited TRAF6/ROS-dependent activation of the MAPK and NF-κB signaling pathways in RANKL-induced RAW264.7 cells, and these effects were partially reversed by HO-1 silencing or TRAF6 overexpression. These findings suggest puerarin alleviates loss of bone mass in the OVX-model mice by suppressing osteoclastogenesis via inhibition of the TRAF6/ROS-dependent MAPK/NF-κB signaling pathway.