Fig. 1.

Periganglionic inflammation (PGI). (A) Procedure for surgical treatment of PGI. After identifying L5 process (A-1), the process was cut to visualize L4 nerve (A-2). Cotton gauze with CFA or saline was put onto the nerve (A-3). Acute inflammation of the L4 spinal nerve produced by CFA application immediately distal to the L4 DRG. (B) Immunohistochemistry for CD11b, a marker for activated macrophages shows the accumulation of immune cells at the site of the CFA application and in the DRG. Red CD11b, blue DAPI nuclear staining. CD11b positive cells were not observed in DRGs from naive animals. (C) Hematoxylin–Eosin (HE) staining of the DRG from PGI animals. No sign of mechanical compression was observed. Arrows indicate inflammation site. Scale bar = 500 μm. (D) HE staining of the skin of the hindpaw from PGI and naive animals. No inflammatory reaction (inflammatory cell accumulation or tissue edema) was observed in the paw. Scale bar = 200 μm.