Gold nanoparticles inhibited the receptor activator of nuclear factor-κb ligand (RANKL)-induced osteoclast formation by acting as an antioxidant.

Gold nanoparticles inhibited osteoclast (OC) formation induced by the receptor activator of nuclear factor-κB ligand (RANKL) in bone marrow-derived macrophages (BMMs). This was accompanied by a decreased level of tartrate-resistant alkaline phosphatase (TRAP) and less activation of nuclear factor (NF)-κB. The nanoparticles also reduced the production of reactive oxygen species (ROS) in response to RANKL and upregulated RANKL-induced glutathione peroxidase-1 (Gpx-1), suggesting a role as an antioxidant in the BMM. The inhibitory effects on OC formation might have been due to elevated defense against oxidative stress.