Age-related changes in the temporomandibular joint of the senescence accelerated mouse. SAM-P/3 as a new murine model of degenerative joint disease.

Age-related changes of the condyle of the temporomandibular joint (TMJ) in strains of Senescence Accelerated Mouse (SAM) were investigated. With advancing age, all strains of SAM showed degenerative joint disease initiated by degenerative changes such as eg, roughness, fissure, and erosion on the condylar surface. These degenerative changes were in concert with an active remodeling that can lead to deformation of the condyle. Moreover, the short-lived SAM-P (accelerated senescence prone mouse) strains developed these degenerative changes earlier than did the SAM-R (accelerated senescence resistant mouse) strains. Thus, development of degenerative joint disease in SAM was closely related not only to chronological age but also to the accelerated senescence phenomenon. Of the SAM-P series, the SAM-P/3 strain was the first to manifest degenerative changes (approximately 50% at 7 to 9 months of age and 100% over 12 months of age) and thereafter showed the highest incidence of severe changes with overt deformity. As a model of degenerative joint disease, this strain of SAM should prove useful.