A role for apoptosis in temporomandibular joint disc degeneration : a contemporary review

The temporomandibular joint (TMJ) connects the mandible to the skull. TMJ disorders induce degenerative tissue changes in TMJ disc that are largely the result of maladaption to abnormal joint loading. Histopathological studies have documented an association between TMJ arthropathy and loss of tissue cellularity, via apoptosis-related processes, that result in diminished extracellular matrix generation, organization, and repair. However, the exact molecular mechanisms underpinning the development and progression of such degenerative changes are still unclear. We review the most recent findings regarding the involvement of apoptotic mechanisms in TMJ disc degeneration. Although a number of aspects of TMJ disc degeneration have been thoroughly investigated, data on the involvement of apoptotic mechanisms and their mediators are few and quite recent; indeed most of the research conducted on fibrous cartilage apoptosis has focused on the intervertebral disc.