Chromatin immunoprecipitation analysis of keratinocyte-derived chemokine (KC) and CXCR2 in spinal cord tissue at day 1 after incision. Histone acetylation in KC (A) and CXCR2 (B) promoter region in spinal cord significantly increased at 1 day after incision in mice treated with suberoylanilide hydroxamic acid (SAHA) compared with mice treated with vehicle. Values are displayed as the mean ± SEM; n = 5; *P < 0.05 versus vehicle group. CXCR2 = chemokine CC motif receptor 2.