Nerve Conduction Evaluation after Injury

To assess nerve conduction of the injured nerve, the mice were anesthetized with 180 mg/kg tribromoethanol post 3 weeks after surgery, and electrophysiological examination was performed as previously reported [14 (link), 37 (link)]. Briefly, a pair of needle electrodes were inserted to stimulate the sciatic nerve 3 mm proximal to the crush site, and a pair of recording electrodes were inserted subcutaneously into the middle of the intrinsic foot muscle. After a single stimulation with a strength of 10 mA and a duration of 0.1 ms, the amplitude and latency of the compound muscle action potential were recorded with a set of electrophysiological recorders (frequency of 20 Hz and pulse width of 0.1 ms) (Axon Digidata 1550 Digitizer, Molecular Devices, Sunnyvale, CA, USA). Immediately after the electrophysiological testing, the mice were transcardially perfused with 4% PFA, and the gastrocnemius muscles and sciatic nerves were collected for histomorphometry examination, Western blotting or immunofluorescence.