Figure 2.

Efficiency of myelin clearance in the distal sciatic nerve of CCR2 −/− mice is comparable to that in WT mice despite the total absence of axotomy-induced macrophage infiltration into the distal nerve in the knockout animals (see Niemi et al., 2013). Seven days after the sciatic nerve was unilaterally transected, changes in reactivity for myelin proteins were determined in nerves from WT, Wld^s, and CCR2 −/− mice by staining with LFB. The distal nerve segments from WT and CCR2 −/− mice showed significantly less myelin staining compared with contralateral nerves, whereas axotomized nerves from Wlds mice retained >80% of myelin reactivity compared with contralateral nerves (a). The micrographs represent sections from the ipsilateral (e-g) and contralateral (b-d) nerves from WT, Wld^s, and CCR2 −/− mice, respectively. Infiltrating macrophages have been considered necessary for the phagocytosis and clearance of myelin debris after injury; however the reduction in this cell population at the distal sciatic nerve does not hinder the clearance mechanism. *p<0.05, **p<0.001. Scale bar, 20 μm. (Niemi et al., 2013)