Application of recombinant IL-1β and its deficiency influence lesion size after spinal cord compression injury. (A) to (D) Quantification of the lesion size and lesion width based on a clearly distinguishable Iba1-positive area. Lesion size measurement in the central sections of recombinant IL-1β (rIL-1β)-treated mice indicated no difference compared with controls (A), while the lesion width was about 20% greater (B). Both the lesion size (C) and the lesion width (D) were reduced by 40% and 25%, respectively, in IL-1βKO mice compared with controls. (E) Representative micrographs of Iba1 immunoreactive microglia distribution around the compression injury site in spinal cord sections. Upper panels: comparison of PBS-treated and IL-1β-treated spinal cord. Lower panels: comparison of wildtype control with IL-1βKO spinal cord. Dashed line, area of the lesion. Iba1 intensity did not differ significantly between groups (data not shown). *P <0.05; n = 5 mice (PBS), n = 5 mice (rIL-1β), n = 7 mice (C57BL6/J), n = 5 mice (IL-1βKO). Scale bar = 100 μm.