Figure 2. Repopulated microglia and macrophages are able to engage in the development of neuropathic pain.

(a) Representative images showing repopulation of Iba1-positive spinal microglia at POD14 in control and pre-SNT ablation mice. Scale bar, 100 μm. (b) Graphical representation showing the time course of ablation and repopulation of dorsal horn microglia in both ipsilateral and contralateral sides after SNT in control and ablation groups (n=3 mice for each group, n=3 images for each animal, ***P<0.001, ablation ipsi versus control ipsi, t-test). (c) Representative images showing macrophage repopulation in the contralateral and ipsilateral DRGs at POD14. Scale bar, 50 μm. (d) Time course of macrophage repopulation in the contralateral and ipsilateral DRG after SNT in control and ablation groups (n=3 mice for each group, n=3 images for each animal, *P<0.05, ***P<0.001, ablation ipsi versus control ipsi, t-test). (e) An experimental diagram showing the timeline of experiments (upper) and a representative image showing the repopulated microglia in the spinal dorsal horn at POD7 after SNT (lower). Scale bar, 100 μm. (f) Mechanical allodynia after SNT in post-ablation mice when microglia and macrophages were repopulated. Data represent average 50% paw withdrawal threshold±s.e.m. (n=6 for each group; P>0.05 for all testing points, post-ablation ipsi versus control ipsi, U-test). CX₃CR1^CreER/+:R26^iDTR/+ mice with DT only were considered to be controls and mice with both TM+DT treatment was ablation group.