Histopathology of the spinal cord in IL-1R KO and wild-type mice. (A) H & E staining of the spinal cord showed infiltration of inflammatory cells in knockout (KO) mice (c, d) and little infiltration in wild-type (WT) mice (a, b). Luxol Fast Blue (LFB) staining of adjacent sections showed irregular vacuolation and minor demyelination in the white matter of KO mice (g, h) but no loss of myelin in WT mice (e, f). Bielschowsky silver staining of the same area shows the presence of irregular vacuolation and minor axonal loss in KO mice (k, l) but not in WT mice (i, j). Magnification, ×10 and ×40. Black arrows indicate regions of lymphocyte infiltrates, demyelination, or axon loss; thin black squares indicate the areas from the lumbar spinal cord region, which are shown in high magnification (b, f, and j for B6 mice and d, h, and l for IL-1R KO mice). (B) H & E staining of spinal cords of control (a) and IL-1R KO mice (c) are shown. The adjacent sections (b and d, respectively) were stained with anti-CD45 antibody (red) for infiltrating cells and counterstained with 4',6-diamidino-2-phenylindole (DAPI) (blue) for nuclei.