Up-regulation of interleukin-6 and vascular endothelial growth factor-A in the synovial fluid of temporomandibular joints affected by synovial chondromatosis

Abstract Our aim was to explore important inflammatory mediators for synovial chondromatosis in the temporomandibular joints (TMJs) by analysing synovial fluid. Samples were collected from 10 patients with unilateral synovial chondromatosis of the TMJ. Control samples were obtained from 11 subjects with no symptoms in the TMJ. Concentrations of aggrecan, interleukin (IL)-2, IL-4, IL-5, IL-6, IL-8 (CXCL8), IL-10, interferon (IFN)-γ, tumour necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF)-A were measured in the samples of synovial fluid, and the results in the two groups compared. The tissues from the affected TMJ were examined histologically and immunohistochemically. Of the proteins evaluated, the concentrations of aggrecan, IL-6, and VEGF-A were significantly higher in the group with synovial chondromatosis. The immunohistochemical analysis showed that the synovial cells around the osteocartilaginous nodules were vigorously expressing VEGF-A. IL-6 and VEGF-A are thought to have important roles in the pathology of synovial chondromatosis of the TMJ.