Platinum nanoparticles suppress osteoclastogenesis through scavenging of reactive oxygen species produced in RAW264.7 cells

Recent research has shown that platinum nanoparticles (nano-pt) efficiently quench reactive oxygen species (ros) as a reducing catalyst. ros have been suggested to regulate receptor activator of nf-κb ligand (rankl)-stimulated osteoclast differentiation. in the present study,we examined the direct effects of platinum nano-pt on rankl-induced osteoclast differentiation of murine pre-osteoclastic raw 264.7 cells. the effect of the nano-pt on the number of osteoclasts was measured and their effect on the mrna expression for osteoclast differentiation was assayed using real-time pcr. nano-pt appeared to have a ros-scavenging activity. nano-pt decreased the number of osteoclasts (2+ nuclei) and large osteoclasts (8+ nuclei) in a dose-dependent manner without affecting cell viability. in addition,this agent significantly blocked rankl-induced mrna expression of osteoclastic differentiation genes such as c-fms,nfatc1,nfatc2,and dc-stamp as well as that of osteoclast-specific marker genes including mmp-9,cath-k,clc7,atp6i,ctr,and trap. although nano-pt attenuated expression of the ros-producing nox-family oxidases,nox1 and nox4,they up-regulated expression of nox2,the major nox enzyme in macrophages. these findings suggest that the nano-pt inhibit rankl-stimulated osteoclast differentiation via their ros scavenging property. the use of nano-pt as scavengers of ros that is generated by rankl may be a novel and innovative therapy for bone diseases. © the japanese pharmacological society.