OPG/RANK/RANKL system in fracture and rheumatoid arthritis

It is an important discovery that the osteoprotegerin(OPG)/receptor activator of nuclear factor kappa B(RANK)/RANK ligand(RANKL)system is in the research of bone metabolism.OPG/RANK/RANKL system plays a vital role in the regulation of bone modeling and remodeling.We here review the OPG/RANK/RANKL system and summarize its functions in osteoporotic fracture,such as the relationship between RANKL/OPG ratio and fracture,the effect of OPG and RANKL to fracture healing etc.We also introduce the relationship between OPG/RANK/RANKL system and rheumatoid arthritis pathogenesis.