Figure 7.

Altered numbers of neutrophils and monocytes in the injured spinal cord in Lcn2^−/− mice. Representative density plots of fluorescence-activated cell sorting analysis of cells isolated from injured spinal cord at 2 dpi. All CD45⁺ cells (A, D, R5) were further gated on Mac-1 labeling (B, E). In B and E, two distinct populations of Mac1⁺ cells can be observed, i.e., the CD45^high (box labeled R7) and the CD45^low (box labeled R10) populations. The CD45^high population are a mixed population of blood-derived immune cells, whereas the CD45^low population comprises resident microglia from the spinal cord. The blood-derived leukocyte population (R7) was further gated on Gr-1 labeling (C, F). Two Gr-1⁺ populations emerge, Gr-1^high (box labeled R8) and Gr-1^low (box labeled R9). The Gr-1^high population is composed of neutrophils, whereas the Gr-1^low population is made up of monocytes. There is a significantly smaller Gr-1^high population in Lcn2^−/− injured spinal cords and a significantly larger Gr-1^low population in Lcn2^−/− injured spinal cord than in wild-type controls [p < 0.05, 2-tailed t test, n = 6 for wild-type (WT), n = 5 for knock-out (KO)]. Gr-1^high in WT = 59.5 ± 0.86%, in KO = 49.6 ± 0.97%. Gr-1^low in WT = 25.1 ± 0.51%, in KO = 30.3 ± 0.82% (mean ± SEM).