Expression of receptor activator of nuclear factor-κb ligand in synovial tissue: Comparison with degradation of articular cartilage in temporomandibular joint disorders

ObjectiveThe present study was performed to investigate the correlations between expression of the receptor activator of nuclear factor-κB ligand (RANKL) in synovial tissue and the degrees of synovitis, degeneration of articular cartilage, and adhesions in patients with internal derangement (ID) of the temporomandibular joint (TMJ).Study designExpression of RANKL, detected immunohistochemically, and the severity of arthroscopic features (synovitis, degenerative changes of articular eminence, and adhesion) in 30 patients with ID of the TMJ were assessed and the correlations between them were analyzed statistically.ResultsRANKL expression was detected in the cytoplasm of synovial lining cells, endothelial cells, and fibroblast cells. However, there were no correlations between RANKL expression in any cell type and the severity of arthroscopic features.ConclusionThese observations indicated that the cellular source of osteoclastic differentiation exists in TMJ with ID and may provide insight into the mechanism of osteoclast differentiation.