Effect of MK801 treatment on CD8 beta T-cell infiltration. By immunohistochemical analysis we also analyzed levels of CD8+ beta T-cell infiltration. There was no staining for CD8+ beta T lymphocytes in spinal cord obtained from sham-operated mice (a). Instead CD8+ beta cells were observed in the spinal cord tissue collected from SCI-mice (b), on the contrary, CD8+ beta T lymphocytes infiltrates were significantly attenuated in MK801 MK801(2 mg/kg 30 min and 6 h after SCI induction)-treated mice (c). Densitometry analysis of immunohistochemistry photographs (n = 5 photos from each sample collected from all mice in each experimental group) for CD8+ beta (d) 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.