PNI model

We used the spinal nerve injury model with some modifications (Ho Kim and Mo Chung, 1992; Kohro et al., 2020). The mice were deeply anesthetized with 0.3 mg/kg medetomidine hydrochloride, 4 mg/kg midazolam, and 5 mg/kg butorphanol, and a small incision was made at L3–S1. The paraspinal muscle and fat were removed from the L5 transverse process, which exposed the parallel-lying L3 and L4 spinal nerves. The L4 nerve was then carefully isolated and cut for PNI model, or was left intact for sham model. The wound and the surrounding skin were sutured with cotton thread.