[Animal models for bone and joint disease. Osteoarthritis development in experimental mouse models induced by mechanical stress].

Little is known about molecular mechanism underlying osteoarthrits. Our mouse genetics approaches by mechanical stress induced OA models found that the proteinases produced during the endochondral ossification process cause cartilage degradation at the center of the joint and osteophyte formation at the periphery. At the periphery, vascularity is accessible from the synovium or tendon, which completes endochondral ossification and forms osteophytes, just as it does at the embryonic and growth plate cartilage. However, in the center, the vascularity is not accessible from the edge, so that it may end up with cartilage degradation without being replaced by bone. Molecules related to the endochondral ossification will be a therapeutic target of osteoarthritis, so our experimental mouse models are useful tools for elucidation of the molecular mechanisms.