Figure 6. Homing of M2 Monocyte-Macrophages to the Injured Parenchyma through the Cerebrospinal Fluid.

(A–C) Quantification of GFP⁺ cells in Cx3cr1^GFP/+ chimeras after SCI (A) in sections (30 μm) of brains and SC. # in segments of 0.5 cm; n = 4–8 mice per time point. ANOVA: F = 4.7, *p < 0.0001 relative to uninjured.

(B) GFP⁺ cell count in the CSF assessed by flow cytometry (results are presented as cell count per 100 μl CSF). n = 4–6 pools (of 8–12 mice); Student’s t test; * relative to uninjured.

(C) GFP⁺ cell count in the CSF presented as percentages of live cells, as determined by flow cytometry. Dashed line represents blood monocyte percentages. n = 4–6 pools (of 8–12 mice); Student’s t test; * relative to uninjured.

(D) GFP⁺ cells in association with vimentin-immunoreactive fiber structure at the edge of the central canal (delineated by Vimentin) of injured Cx3cr1^GFP/+ chimeras. n = 3 mice.

(E) SC sections immunostained for visualization of GFP⁺ cells in the central canal (delineated by Vimentin or Hoechst) of injured Cx3cr1^GFP/+ chimeras. n = 3 mice each.

(F) Central canal stained for vimentin together with ICAM-1 (i) or SDF-1(ii).

(G and H) Cx3cr1^GFP/+ chimeras were subjected to SCI concurrently with intracisternal Matrigel injection, and at d7, their SC were analyzed for monocyte-macrophages. Student’s t test: (G) n = 5–7 mice, p = 0.02; (H) n = 6–8 mice; Ly6c^loCx3cr1-GFP^hi p = 0.02; Ly6c^hiCx3cr1-GFP^lo p = 0.66; one experiment representative of three. In (H), cells from both gates were plotted on the same histogram. Absolute numbers of cells in 0.5 cm SC tissue, per 20,000 CD11b⁺ cells, are indicated.

Data are represented as mean ± SEM. Scale bars represent 20 μm in (D) and 10 μm in (E) and (F). See also Figure S4.