[Animal models for bone and joint disease. Osteoimmunology and animal models for rheumatoid arthritis].

Bone homeostasis is maintained by not only bone cells but also by various types of cells. Particularly, the skeletal system has an apparent relationship with the immune system, in that immune cells are generated in the bone marrow and that osteoclasts which play a crucial role in bone destruction differentiate from monocyte/macrophage lineage cells. In addition, investigation into rheumatoid arthritis (RA) has highlighted the relevance of the interplay between the bone and immune systems and promoted a new research field of 'osteoimmunology'. Here, we summarize how various animal models for RA contributed, and can contribute to the progress in osteoimmunology and increasing understanding of RA development and treatment.