Examination of nerve electrophysiology

To determine the compound muscle action potential (CMAP), rats were anesthetized by inhalation of 4% isoflurane, while the body temperature was maintained at 37.0°C with an electric heating blanket. After the sciatic nerve was exposed on the operative side as described above, a neural needle electrode, which was used to deliver the electrical stimulation, was placed 5 mm from the proximal part of conduit suture site, and the reference electrode was placed in the gluteus maximus. For CMAP waveforms recording, two recording electrodes were inserted at the two ends of the gastrocnemius muscle. A single electrical pulse, with an intensity of 1 mA and a duration of 0.1 ms, was used to stimulate the trunk of the regenerated nerve. CMAP latency and amplitude were recorded using an electrophysiological monitoring device (YRKJ-G2008; Zhuhai Yiruikeji Co, Ltd, Guangdong, China).