Less proinflammatory cytokine induction was evident in IL-1 KO mice after SCI. (A) IL-1β levels in the spinal cords of wild-type mice (open squares and solid line) were drastically increased from the 1st dpo and sustained through to the 14th dpo. No IL-1β was detected in the IL-1 KO mice (data not shown). (B) TNFα level in the spinal cord of the wild-type (open squares and solid line) and IL-1 KO mice (closed square and dotted line). TNFα expression in the wild type mice was increased from the 1st dpo and remained elevated through to the 14th dpo. However, TNFα levels in the IL-1 KO mice remained relatively unaltered post-operatively and were significantly lower than those in the wild-type mice. Data are expressed as mean ± SE. **: P <0.01 (Student's t-test). (C) Merged images of immunostaining for IL-1β and the microglia/macrophage marker, Iba-1. Minimal overlap of staining is observed between IL-1β, NSE and GFAP. Nuclei staining was detected with DAPI. DAPI, 4, 6-diamidine-2-phenylindole dihydrochloride; Dpo, days post-operatively; SCI, spinal cord injury.