Figure 5.

FMN numbers and immune responses are unaltered in Atf3^−/− animals. (a–d) Nissl staining was employed to label all FMNs present in FN. No major FMN loss was observed upon lesion in wt (c) or Atf3^−/− (d) mice. (e–l) Microglia (e–h) and astrocytes (i–l) were labelled at 8 d.p.l for IBA-1 and GFAP expression, respectively. In the uninjured FN of wt (e,i) or ATF3-deficient (f,j) animals, no IBA-1 positive microglia (e,f) or GFAP positive astrocyte (i,j) cell infiltration was observed. By contrast, upon injury (g,h and k,l) there was a comparable microglia and astrocyte activation in wt (g,k) and Atf3 mutant (h,l) animals. (m–p) CD4⁺ cells were found on the unlesioned side of wt (m) and Atf3 mutant (n) animals. CD4⁺ T cells were slightly upregulated upon lesion in wt (o) as well as Atf3 mutant (p) FNs. (q–t) CD45, a marker for CNS infiltrating monocytes, was nearly absent on the unlesioned FN (q,r). Facial nerve lesion increased CD45 positive cells on the FN of wt (s) and Atf3 mutant (t) animals. Insets in (e–t) show higher magnifications of areas marked with a dashed box. (u–y) The percentage of Nissl positive FMNs on the lesioned FN (control side set to 100%; u), total area (in square micrometres) of GFAP positive astrocytes (v), number of IBA1 positive microglia (w), number of CD4⁺ cells (x) or total area (in square micrometres) of all CD45⁺ cells (y) per section were counted and plotted against the different timepoints. Each circle or square in (u–y) represents one mouse. Data are presented as mean ± s.d. Scale bar (a–t) = 100 µm; insets (e–t) = 5 µm.