Matrix metalloproteinase and tissue inhibitor of metalloproteinase in serum and lavage synovial fluid of patients with temporomandibular joint disorders

SUMMARY. We measured matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMP) in temporomandibular joint (TMJ) disorders. All patients were fully investigated, by visual analogue pain scores, plain radiographs and double-contrast arthrotomograms. The patients were grouped according to whether or not they were in pain. There were 35 patients with painful joints; 16 painless crepitating joints and 10 with chronic closed locked joints. A further group of 9 volunteers with no symptoms of TMJ abnormalities were used as controls. We found that synovial fluid concentration of MMP-3 was significantly increased (1117.2 (164.0) ng/ml) (P< 0.05) in the painful group compared with controls (436.2 (94.8) ng/ml) and with the two groups with painless TMJ (475.0 (113.0) ng/ml/crepitation, and 516.0 (115.1) ng/ml/closed locked joints). MMP-1 and TIMP-1 were not recordable in most joints, and the serum concentrations of MMP-1, MMP-3, and TIMP-1 were similar to those in controls in all groups. There was no correlationship between MMP-3 concentration and joint morphology as shown by plain radiographs and double contrast arthrotomograms. These findings indicate that the synovia of painful joints are inflamed.