Fig. 3

Hydrogen decreased MMP-9 activity and ASK1 phosphorylation to attenuate postoperative pain in mice. Mice were administrated HRS (5 mL/kg, i.p., twice daily), the phosphorylation and expression of ASK1 (A), p38 (B) and JNK (C), the activity and expression of MMP-9 (D, E), the expression of IL-1β and pro-IL-1β (F) were measured using western blot and zymography in the spinal cord (n = 6). G–I The expression of IL-1β, IL-6, and TNF-α were measured using Elisa kit. J, K Mechanical allodynia after plantar incision surgery was measured using the von Frey test (n = 12). Lumbar spines (L4–L5) were collected and analyzed 5 days after surgery. HRS = hydrogen-rich saline; PI = plantar incision; Veh = vehicle. Significant difference is revealed following one-way ANOVA (A–F) or two-way ANOVA (G, H) (*P < 0.05, **P < 0.01, ***P < 0.001 vs. sham; ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 vs. PI group; Bonferroni post hoc tests)