Histograms showing the percentage of ATF3+ nuclei in the proximal (A) and distal (B, C) stumps of injured sciatic nerves in adult rats. The data in Figs. 2A and 2B are from animals in which the sciatic nerve was cut and a segment resected, resulting in restricted regeneration. The ATF3+ nuclei in the proximal stumps were more weakly stained as well as less numerous than those in the distal stump. There is no bar for 4 dpo in Fig. 2A because so few nuclei were ATF3 immunoreactive (<1%). Fig. 2C allows a comparison between the number of ATF3+ nuclei in the distal stumps of nerves that were cut and reanastomosed, to allow axonal regeneration, and nerves which were cut and ligated, to prevent regeneration. It is apparent that axonal regeneration into distal stumps is associated with a downregulation of ATF3.