Fig. 1

Neonatal inflammatory pain increased inflammatory cytokines in the blood and cortex. Quantitative RT-PCR (qRT-PCR) analysis was performed to measure inflammatory factors in blood samples and cortical tissues. a The levels of TNF-α, IL-1β, and IL-6 in the blood 1 day after the 3-day formalin injections, TNF-α and IL-1β significantly increased in both male and female rats; indomethacin (Indo) co-applied with formalin blocked the inflammatory reaction. b TNF-α, IL-1β, and IL-6 levels in the cortex 1 day after formalin injection. Only the TNF-α level was significantly enhanced in the male brain. Indomethacin (Indo) showed inhibitory effect on TNF-α expression. c Inflammatory factors were measured in blood samples 16 days after formalin injections (P21 rats). TNF-α and IL-1β increased in male but not in female rats in the formalin group, which were blocked by indomethacin (Indo). d Increased levels of TNF-α and IL-1β persisted in the male brain cortex 16 days after formalin injections. Indomethacin (Indo) blocked these increases. *P < 0.05 vs. control, ^# P < 0.05 vs. formalin group, ANOVA plus Bonferroni’s correction; n = 4 per group