H3 delays axonal regeneration after nerve transection in mice. (A, B) Development of CMAP amplitude (A) and conduction velocity (B) in unoperated (Intact) and operated (Lesion) nerves in the vehicle (Veh)- and H3-treated animals. (C) Recovery of the functional index (SFI). (D, E) Total number of fibers (D) and myelinated fiber distributions (E, right) at 8 wks after lesion. (E, left) Representative images of regenerated sciatic nerves from the vehicle- and H3-treated animals at 8 wks after transection, 50 × 50 μm fields are shown. (A–E) *p < 0.05 versus Veh, two-tailed t test. (A–C) Number of animals, n = 7/7 (Veh/H3). (D, E) n = 4/4.