Subcellular localization of high mobility box group 1 (HMGB1) in L5 dorsal root ganglion (L5
DRG) primary afferent neurons following tibial nerve injury (TNI) in rats. (A) Sections of L5DRG stained for HMGB1 immunoreactivity (−IR) are localized primarily to the nuclei of both neuronal and non-neuronal cells (A1; arrows) in the naive L5DRG. (B) By post-injury day (PID) 14, HMGB1-IR is localized to the cytoplasm of L5DRG neurons (B1; arrowheads). There are some nuclei of non-neuronal cells that also exhibit HMGB1-IR (B; arrows). (C) Cell counts performed on sections of sensory ganglia derived from naïve, sham and TNI animals revealed that a large number of sensory neurons exhibit HMGB1 in the cytoplasm (*P < 0.01). (D) Naïve sections of L5DRG stained for activating transcription factor 3 (ATF3)-IR. (E) By PID 14, ATF3-IR is localized to the nucleus of L5DRG neurons (arrow). Scale bar 50 μm.