The relationship between collagen metabolism and temporomandibular joint osteoarthrosis in mice

The histologic changes in the temporo mandibular joint (TMJ) and the activity of serum collagenase-like (CL) peptidase and prolyl endopeptidase (PEP) were compared in mice with spontaneous osteoarthrosis (C57 black mouse/6 Silverberg (C57BL/6S) and control mice (C57 black mouse/6N (C57BL/6N) and ddY). The onset of osteoarthrosis of the TMJ in the C57BL/6S mice was noted at 12 weeks of age. Clefting in the chondrocyte layer was noted at 24 to 36 weeks of age; chondrocyte cluster and pannus at 36 to 60 weeks of age; and clefts deep in the bone and formation of osteophytes at 72 to 96 weeks of age. CL-peptidase and PEP activity significantly higher in C57BL/6S mice than in osteoarthrosis-free C57BL/6N and ddY mice. These changes occurred at an earlier age than the histologic changes. The findings suggest that these enzymes may play a significant role in the onset of osteoarthrosis in joints.