MK801 treatment reduced CD30 and CD30-ligand expression. Spinal cord sections were processed 24 h after SCI to determine the immunohistological staining for CD30 and CD30-ligand expression. No positive staining for CD30 (a) and CD30-L (d) was found in the spinal cord tissue from sham-operated mice. A substantial increase in CD30 (b) and CD30-L (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 CD30 (c) and CD30-L (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 CD30 and CD30-L (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.