an Original Chemical Model of Osteoarthritis in Rabbit Temporomandibular Joint

Objectives: Epidemiological studies have shown a tight clinical association between temporomandibular joint (TMJ) osteoarthritis and disc derangement. Biomechanical models of TMJ osteoarthritis by disc displacement, disc perforation or discectomy are of primary importance in understanding the degenerative mechanisms involved in joints with internal derangement. Nevertheless, post-mortem studies demonstrated that osteoarthritis could also occur in TMJ without disc displacement. In such cases, information concerning the onset of degenerative changes is lacking. In order to explore this issue, a chemical model of knee joint osteoarthritis, induced by sodium mono-iodoacetate (MIA), was transposed to TMJ. Methods: Twelve New-Zealand white rabbits were used to validate this original technique of intra-capsular injection and to document by histology the effect of this drug on TMJ. Nine rabbits underwent bilateral MIA injection in the lower compartment, using two different concentrations, while three served as control. Rabbits were sacrificed 10, 20 and 30 days after injection and the joints were prepared for undecalcified histology. Results: The success rate of this half-blind technique in producing articular defects was 87.5%. Severity of the damages was time- and dose-dependant and both concentrations allowed to observe, within 30 days, all osteoarthritis stages usually described in the literature. In all joints the defect was surrounded by hypertrophic cartilage changes, consistent with an initial and repair stage of osteoarthritis. With the higher MIA concentration, a disk perforation secondary to cartilage changes occured at 10 days. Conclusions: Iodoacetate injection appeared to be a simple and reliable method to induce degenerative changes in rabbit TMJ. It may constitute a complementary and a mini-invasive alternative model to study osteoarthritis in this particular joint.