Figure 2:

Histology and immunohistochemistry. Controls: a1: hematoxylin-eosin (HE) sagittal view of the cord: notice poor take-up of the stain by interface tissues. a2: chromotropic acid 2R-Brilliant Green (C-2R-G) staining of an axial slice showing widespread Wallerian degeneration. a3: C-2R-G stained sections above, at and below injury level: notice absence of axons across the interface. a4: neurofilament 200 (NF200) DAPI and 5HT DAPI sections. Notice near absence of regrowing fibers across the interface. Polyethylene glycol: b1: HE sagittal view of the cord: notice bright coloring as stains are taken up by treated tissues. b2: C-2R-G staining of an axial slice showing widely conserved axons at the interface (arrows). b3: C-2R-G stained sections above and below injury level: notice the abundance of axons across the interface. b4: NF200 DAPI and 5HT DAPI sections. Notice regrowing fibers across the interface.