Fig. 1.

Cold allodynia triggered by unilateral tibial fracture. (A) Mice with fracture do not develop tactile allodynia or mechanical hypersensitivity after surgery but have exaggerated responses to cold stimulus from day 3 (3d), lasting for at least the 14 d (14d) that were recorded in this study. (B) Mice processed for sham surgery also develop mild cold allodynia. BL, baseline; Contra, contralateral; Ipsi-, ipsilateral. Data for tactile allodynia from von Frey filament tests (nonparametric data) are represented as box and whisker plots (analyzed with unpaired Mann–Whitney test), whereas withdrawal durations for pinprick and acetone stimuli are represented as mean ± SD. Experimental group, n = 5–9; sham group, n = 6. **P < 0.01; analyzed with unpaired t test.