ESTABLISHMENT OF A RAT MODEL OF TEMPOROMANDIBULAR JOINT OSTEOARTHRITIS USING INTRAARTICULAR INJECTION OF COMPLETE FREUND’S ADJUVANT

Abstract

Osteoarthritis is a common progressive joint disease,
involving not only the joint lining but also cartilage,
ligaments, and bone. Osteoarthritis (OA) of the
temporomandibular joint is a unilateral,
degenerative disease of the jaw joint. It is
characterized by breakdown of the articular
cartilage, architectural changes in bone, and
degeneration of the synovial tissues causing pain
and/or dysfunction in functional movements of the
jaw. Temporomandibular joint osteoarthritis (TMJ
OA) is an important etiology of temporomandibular
pain. The temporomandibular joint (TMJ) undergoes
degenerative changes among patients who suffer
from arthritis, and yet the pathogenesis of TMJ
osteoarthritis and rheumatoid arthritis is poorly
understood. However, until recent years, OA of the
temporomandibular joint was confusing, relatively
unrecognized, and difficult to diagnose and manage
and the specific mechanisms of TMJ OA in the
development of temporomandibular pain are still
not clear. Animal models are useful tools for the
investigation of association between animal
behavioral and TMJ OA. Several animal models of
TMJ OA have been established using intraarticular
injection of various chemicals. This study aimed to
establish a rat model of TMJ OA using complete
Freund’s adjuvant (CFA). Histopathological change
with hematoxylin-eosin staining and radiographic
change of the TMJ was performed. Treatment with
CFA induced cartilage damage, synovitis, and
proliferation of synovial cells in the fact joints. A rat
model of TMJ OA was successfully established using
intraarticular injection of CFA. This animal model is
convenient and shows good resemblance to human
OA pathology. We hypothesized that inflammation
in the TMJ induces structural abnormalities, and
accordingly characterized the disc and synovium in a
novel model with double injections of complete
Freund’s adjuvant (CFA), using histopathological
change with hematoxylin-eosin staining and
radiographic examinition.