(a) CSF1 induction in DRG neurons ipsilateral to the nerve injury co-localizes with NPY (Inset), a neuropeptide that is only expressed in sensory neurons after injury (1 d). Scale bars represent 200 μm and 10 μm (Inset); (b) Accumulation of CSF1 and NPY at the dorsal root ligature (4d post injury). Co-localization of CSF1 with NPY establishes that the CSF1 transport is intra-axonal. Dashed line denotes ligature. Scale bar represents 200 μm; (c) CSF1R (immunostaining) co-localizes with the microglial marker CD11b and both markers are induced in the dorsal horn after nerve injury (3 d post injury). Scale bar represents 100 μm; (d) There is complete CSF1R-GFP co-localization with the microglial marker Iba1, and none with the neuronal marker, NeuN. Both CSF1R-GFP and Iba1 are induced in the dorsal horn after nerve injury (3 d post injury). White square shows enlarged region. Scale bar represents 100 μm; (e) Quantification of CSF1R immunostaining in CD11b positive cells in the superficial dorsal horn 3 days after nerve injury; (f) Quantification of GFP intensity in Iba1 positive cells in the superficial dorsal horn 3 days after nerve injury. N = 3–4 mice/group. Data are presented as mean ± s.e.m. *p≤0.05, ***p≤0.001.