To furnish an experimental basis of the early effects of rheumatoid arthritis (RA) on the temporomandibular joint (TMJ) by observing the histopathological changes of TMJ in the early stage of polyarthritis (PA) rats.
The animal model of PA was established by injecting Freund's complete adjuvant (FCA) into rats. The histopathological changes of the rats' ankle joint and TMJ were studied.
(1) The paw volume and the articular index of PA rats increased significantly, and symptoms of pronounced inflammation were present in the ankle joint specimens, which included proliferation of the synovium, infiltration with inflammatory cells, erosion into the articular cartilage and bone, and inflammatory exudation into the articular cavities. (2) The histopathology of TMJ of PA rats showed pronounced proliferation of the synovium cells, some lytic collagenous fibers and degenerative chondrocytes in the condyles, and exudated protein and desquamating cells in the articular cavities with some fibrinous adhesions.
Pronounced inflammation occurs in bilateral TMJ in early stage of PA rats. The examination, protection and treatment of TMJ for RA patients should be taken into account in the early stage.