Effects of COX-2 inhibitor in temporomandibular joint acute inflammation.

Since it is recognized that cyclo-oxygenase-2 mediates nociception and the sleep-wake cycle as well, and that acute inflammation of the temporomandibular joint (TMJ) results in sleep disturbances, we hypothesized that cyclo-oxygenase-2 inhibitor would restore the sleep pattern in this inflammatory rat model. First, sleep was monitored after the injection of Freund's adjuvant (FA group) or saline (SHAM group) into the rats' temporomandibular joint. Second, etoricoxib was co-administered in these groups. The Freund's adjuvant group showed a reduction in sleep efficiency, in rapid eye movement (REM), and in non-REM sleep, and an increase in sleep and REM sleep latency when compared with the SHAM group, while etoricoxib substantially increased sleep quality in the Freund's adjuvant group. These parameters returned progressively to those found in the SHAM group. Etoricoxib improved the sleep parameters, suggesting the involvement of the cyclo-oxygenase-2 enzyme in acute inflammation of the TMJ, specifically in REM sleep.