[Progress of research in osteoarthritis. Molecular targeting for osteoarthritis treatment].

Little is known about molecular mechanism underlying osteoarthrits. Recent mouse genetic approaches by others and us 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. The difference of the two sites may depend on the vascularity. 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.