Fig. 5. Effect of sciatic nerve block with capsaicin on behavior after skin + deep tissue plantar incision and intramuscular injection of H₂O₂.

(A) Effect of sciatic nerve block with capsaicin on guarding behavior after skin + deep tissue plantar incision. Percutaneous sciatic nerve block was performed using 0.05% capsaicin plus 0.5% bupivacaine or 0.5% bupivacaine in vehicle. The results are presented as means ± SD for eight rats in each group. Two-way ANOVA with repeated measures on one factor (interaction factor: F_{7, 98} = 7.913, P < 0.0001) followed by Bonferroni’s post hoc test was used to compare the cumulative pain score at each time point between the groups. * P = 0.0202, † P < 0.0001 compared with the vehicle + 0.5% bupivacaine group at each time point. POD = postoperative day. (B) Effect of peripheral nerve block with 0.05% capsaicin on nociceptive behavior induced by injection of H₂O₂ into the gastrocnemius muscle. H₂O₂ (100 mM, 0.6 ml) was injected into the gastrocnemius muscle at various time points (1, 3, 5, and 7 days) following the nerve block, and the total time spent flinching, lifting, and licking was recorded for 60 minutes. Data are presented as mean ± SD. Capsaicin (0.05%) + 0.5% Bupivacaine group contained 5 rats and vehicle group contained 6 rats. * P = 0.0004, † P = 0.0029, ‡ P = 0.0168 compared with the vehicle + 0.5% bupivacaine group by two-way ANOVA with repeated measured on one factor (interaction factor: F_{3, 27} = 0.9405, P = 0.4348, Time factor: F_{3, 27} = 1.554, P = 0.2233, Group factor: F_{1, 9} = 22.56, P = 0.0010) followed by Bonferroni’s post-hoc test.