[The effects of L-NMMA on experimental temporomandibular joint osteoarthrosis in goats].

Objective: To investigate the effects of repeated injections of L-NMMA on a goat model with osteoarthrotic temporomandibular joint (TMJ) disease.

Methods: Eight goats were selected in this study. Bilateral TMJ osteoarthrosis (OA) was induced by injecting 0.5% collagenase. L-NMMA was injected into one side of TMJs at 4 weeks after collagenase injection (one time every three days). Another joint as control was simultaneously injected using 0.9% saline solution. All goats were killed at 12 weeks after collagenase injection. The TMJ specimens were harvested and processed for histological examination. Modified Mankin's grading score system was used for evaluating changes in the TMJ.

Results: The control side of TMJs showed severe osteoarhrotic changes in the condyle whereas the L-NMMA-treated TMJs showed less degenerative alterations. The histologic score was 3.83 in the L-NMMA treated side, and 6.33 in the control. There was a significant difference in osteoarthrotic changes between the L-NMMA-treated and control TMJs (P < 0.01).

Conclusions: Repeated intra-articular injection of L-NMMA into TMJ may play a role in inhibiting TMJOA progression.