Molecular correlates of temporomandibular joint disease

Objective. The relation between disease severity and the known mediators of pain, inflammation, and tissue damage-prostaglandin E-2 (PGE(2)), leukotriene B-4 (LTB4), malondialdehyde (MDA), nitric oxide (NO), and myeloperoxidase (MPO)-was examined in the synovial fluid of patients with internal derangement (ID) of the temporomandibular joint (TMJ). Study design. Thirty-two patients with ID were classified according to Wilkes by clinical and radiological examinations, and TMJ synovial fluid samples were obtained by arthrocentesis. PGE(2) and LTB4 levels were measured by ELISA kits, MDA levels were determined by a fluorometric method, myeloperoxidase activity was determined by an end-point method, and NO levels were measured by Griess reaction. Results. The earliest significant increase was observed in NO levels (stage 11) and this elevation persisted in the subsequent stages. The first significant elevation in PGE(2) and LTB4 levels and MPO activity were observed in stage III. Both PGE(2) and LTB4 levels were increased in stage III and were correlated with each at this stage and in the subsequent stage. Significant increases in MDA levels were observed only in stage IV. At stage IV there was correlation between MDA and PGE(2), MDA and LTB4, and MDA and MPO. The relation between PGE(2) and MDA was the most powerful one. Conclusion. Results of this cross-sectional study point out the relation between disease severity and levels of some molecular mediators in synovial fluid of TMJ. Longitudinal studies are needed to explore the role of these molecular mediators in the progression of ID.