L5SNT induces degeneration of a proportion of nerve fibers in sciatic nerve. A, B, Morphology showing that L5SNT does not induce axon degeneration to contralateral sciatic nerve (A), whereas it causes axonal injury in ipsilateral nerve (B). C, Morphometry showing that L5SNT induced MF loss in injured side nerve starting on postsurgical day 3. D, CMAP amplitude of the injured side nerve was significantly reduced after L5SNT. E, Micrograph showing axon degeneration in sciatic nerve of DBA/2J mice after L5SNT. F, L5SNT induced ∼5–20% of MF loss in the injured (left) sciatic nerve in wild-type and all mutant/transgenic mice that we tested except for DBA/2J mouse (∼40% MF loss). n = 6. Scale bar, 20 μm.