Fig. 2

Repeated FS induced thermal hyperalgesia in the hindpaw of female rats with orofacial inflammation. a In oil treated groups, only rats with CFA + FS (n = 10) showed a decreased thermal withdrawal latency on day 6 and day 10 post FS when compared to baseline. **, *** p < 0.01, 0.001 vs baseline, respectively. There were not nociceptive changes in rats with FS alone (oil + saline + FS group, n = 9), CFA alone (oil + CFA + non-FS group, n = 8) or all sham treatment (oil + saline + non-FS group, n = 8). b In E2 treated groups, the thermal withdrawal latency significantly decreased on day 2 and day 6 post FS stress in the E2 + CFA + FS group (n = 11). *, *** p < 0.05, 0.001 vs baseline, respectively. FS stress produced thermal hyperalgesia for 10 days after FS (E2 + saline + FS group, n = 8). + p < 0.05 vs baseline. The thermal withdrawal latency significantly decreased on day 2 to day 10 post FS stress in the E2 + CFA + FS rats compared to the sham treated rats (E2 + saline + non-FS group, n = 8). #, ### p < 0.05, 0.001 vs the E2 + saline + non-FS group at the same time point. In rats with FS alone (E2 + saline + FS group), thermal withdrawal latency significantly decreased on day 2 to day 10 post FS stress compared to the sham group. §§§ p < 0.001 vs the E2 + saline + non-FS group at the same time point. No thermal hypersensitivity was observed in rats with CFA alone (E2 + CFA + non-FS group, n = 8) or sham treatment (E2 + saline + non-FS group)