Figure 1: Inflammatory and hypernociceptive dose-response effect of zymosan-induced TMJ arthritis. Zymosan (0.25, 0.5, 1, or 2 mg; 40 μL) or saline was injected i.art. into the left TMJ of the rat. The mechanical nociceptive threshold was measured before and after an i.art. injection of zymosan or saline for 6 hours (a). Leukocyte migration was evaluated by cell counting in TMJ fluid (b). MPO activity was evaluated in TMJ fluid (c) and TMJ tissues (d) for 6 h after an i.art. injection of zymosan or saline. Data are expressed as means ± SEM ( ). versus Sham. versus 0.25, 0.5, and 1 mg groups (ANOVA, Bonferroni).