Effects of MK801 on TNF-α and IL-1β expression in spinal cord tissue. Spinal cord sections were processed 24 h after SCI to determine the immunohistological staining for TNF-α and IL-1β expression. No positive staining for TNF-α (a) and IL-1β (d) was found in the spinal cord tissue from sham-operated mice. A substantial increase in TNF-α (b), and IL-1β (e) expression 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 (c) and IL-1β (f) levels in the spinal cord. Densitometry analysis of immunohistochemistry photographs (n = 5 photos from each sample collected from all mice in each experimental group) for TNF-α and IL-1β (g) from spinal cord tissues were assessed. Figure is representative of at least 3 experiments performed on different experimental days. Data are expressed as % of total tissue area. Data are means ± s.e. of 10 mice for each group.*p < 0.05 vs. Sham. °p < 0.01 vs. SCI. ND: not detectable.