Representative immunohistochemical staining of the brain stem and box-plots of cerebral and cerebellar white matter and brain stem illustrating differences in the number of p75^NTR-(A–F), PDGFR-α-(G–L) and β-APP-(M–R) positive cells per mm² in p75^NTR-/PRX^-, p75^NTR+/PRX^-, and p75^NTR+/PRX⁺ areas as well as unlesioned control tissue.

The number of p75 neurotrophin receptor (p75^NTR) immunopositive cells (A, B, C, D; brain stem; brown) in the cerebral and cerebellar white matter (E) and brain stem (F) is significantly higher in p75^NTR+/PRX⁺ areas in comparison to p75^NTR+/PRX^- areas. There are no differences in the number of PDGFR-α-positive OPCs (G, H, I, J; brain stem; brown; arrows) between any groups of lesioned areas and control tissue, localized in the cerebral and cerebellar white matter (K). In the brain stem (L), p75^NTR+/PRX⁺ areas display significantly higher numbers of PDGFR-α-positive OPCs compared to p75^NTR-/PRX^-, p75^NTR+/PRX^- areas and control tissue. The number of β-APP-positive axons (M, N, O, P; brain stem; brown; arrows) in all lesioned areas within the cerebral and cerebellar white matter (Q) does not show significant differences between the lesioned areas and controls. In brain stem (R) p75^NTR-/PRX^- areas show a significantly higher number of β-APP-positive axons compared to p75^NTR+/PRX^-, p75^NTR+/PRX⁺, and control tissue. Significance was designated as p < 0.05, as detected by Mann-Whitney-U group wise test. All box-plots show median value, lower and upper quartiles, minimum and maximum (excluding outliers). Black circle: extreme value; grey circle: outlier; asterisk: significant differences between respective groups. Scale bars: (A–D) and (M) 100 μm; (G–J), (N) and (O) 50 μm; (P) 20 μm.