Inhibition of Erb B2 improved IENFD in DPN mice. Footpad samples were collected from the plantar surface of the hind paws after 12 (n = 4 per group) or 21 weeks (n = 6–8 per group) of treatment. (A): Representative images of IENFD in non-diabetic (Veh) and diabetic (STZ) mice treated with vehicle (Veh) or erlotinib (Erl). Nerve fibers immunopositive for PGP 9.5 are stained red by the chromagen (arrows) and epidermal cells were stained purple by hematoxylin. (B): Quantification demonstrated a significant loss of nerve innervation in diabetic mice prior to drug administration and erlotinib treatment induced a partial recovery in fiber loss (*, p < 0.05; **, p < 0.01; ***, p < 0.001).