Fig. 1. Pain behaviors of rats with sham procedure, skin, or skin plus deep tissue incision. (A ) Guarding pain behavior measured during a 60-min test period. The results are presented as mean and SEM. Two-way ANOVA (interaction factor: F 18,210= 11.5, P < 0.0001) followed by separate one-way ANOVAs with Tukey post hoc test for comparing the mean cumulative pain score at each time point among groups (2 h: F 2,21= 50.0, P < 0.0001; 1 day: F 2,21= 18.9, P < 0.0001; 2 days: F 2,21= 36.3, P < 0.0001; 3 days: F 2,21= 10.6, P = 0.0006; 4 days: F 2,21= 8.3, P = 0.0022; 5 days: F 2,21= 6.8, P = 0.0051; 6 days: F 2,21= 2.6, P = 0.1016; 7 days: F 2,21= 2.4, P = 0.1163). (B ) Withdrawal threshold to von Frey filament application. The results are presented as median with interquartile range. Friedman test (Fr = 15.2, P < 0.0001) followed by Kruskal-Wallis test with Dunn post hoc test for between-group comparisons at each time point (2 h: KW2,21statistic = 19.1, P < 0.0001; 1 day: KW2,21statistic = 18.3, P < 0.0001; 2 days: KW2,21statistic = 16.7, P = 0.0002; 3 days: KW2,21statistic = 21.0, P < 0.0001; 4 days: KW2,21statistic = 18.2, P = 0.0001; 5 days: KW2,21statistic = 12.0, P = 0.0024; 6 days: KW2,21statistic = 6.5, P = 0.038; 7 days: KW2,21statistic = 2.0, P = 0.37). (C ) Withdrawal latency to heat stimulation. The results are presented as mean and SEM. Two-way ANOVA (interaction factor: F 18,210= 11.5, P < 0.0001) followed by separate one-way ANOVA with Tukey post hoc test for comparing the mean withdrawal latency at each time point among groups (2 h: F 2,21= 170.3, P < 0.0001; 1 day: F 2,21= 152.2, P < 0.0001; 2 days: F 2,21= 100.6, P < 0.0001; 3 days: F 2,21= 31.6, P < 0.0001; 4 days: F 2,21= 33.8, P < 0.0001; 5 days: F 2,21= 8.7, P = 0.0018; 6 days: F 2,21= 3.6, P = 0.0463; 7 days: F 2,21= 2.0, P = 0.1577). *P < 0.5, **P < 0.01, ***P < 0.001 versus sham, †P < 0.5, ††P < 0.01, †††P < 0.001 versus skin incision.
