Effects of MK801 on TNF-α, IL-1β tissue levels and on MPO activity in spinal cord tissue. A substantial increase in TNF-α (a), and IL-1β (b) was found in spinal cord tissues from SCI mice 24 h after SCI. MK801 treatment (2 mg/kg 30 min and 6 h after SCI induction) significantly attenuated TNF-α (a) and IL-1β (b) levels in the spinal cord. Following the injury, MPO activity in spinal cord from SCI mice was significantly increased at 24 h after the damage in comparison to Sham groups (c). MK801 treatment (2 mg/kg 30 min and 6 h after SCI induction) significantly attenuated neutrophils infiltration. Data are means ± s.e. means of 10 mice for each group. *p < 0.01 vs. Sham °p < 0.01 vs. SCI.