Characterization of TLR2 and CCL2 expression in DRG cells. (A) CCL2 is expressed in DRG neurons after nerve injury. DRGs of un-injured WT mice (WT Sham; a, b, and c), injured WT mice at 1 dpi (WT; d, e, and f), and injured TLR2 knock-out mice (TLR2 KO; g, h, and i) at 1 dpi were immunostained with anti-NeuN antibody (shown in red, a, d, and g) and anti-CCL2/MCP-1 antibody (shown in green, b, e, and h). Merged images are shown in the right panels. (B) TLR2 immunoreactivity (red color in a, d, and g) merged with GFAP-IR satellite cells (e) in DRG at 7 dpi, and to Iba-1-IR macrophages (h) in un-injured DRGs, but not to MAP2-IR neurons (b). Merged images are shown in the right panels (c, f, and i). The triangles indicate double-positive cells. Scale bars: 50 μm.