Chronic constriction injury (CCI) surgery

Following baseline (BL) behavioral assessment, the surgical procedure for chronic constriction of the sciatic nerve was performed identically as previously described.^{[21, 22]} Briefly, under isoflurane anesthesia (5% volume in 2.5% in oxygen), the low back and dorsal left thigh was shaved and cleaned with Bacti-Stat AE solution (EcoLab Healthcare Division, Mississuaga, Ontario, Canada). Using aseptic procedures, the sciatic nerve was carefully isolated using sterile glass rods after gentle blunt dissection of overlying muscle, and loosely ligated with 4 chromic gut sutures (Ethicon, Somerville, NJ). The overlying muscle was sutured closed with two sterile silk sutures (Ethicon, Somerville, NJ), and the overlying skin was closed with wound clips. Sham-operated rats underwent the identical manipulation with the exception that the sciatic nerve was not ligated. Animal body weight was recorded and recovery from anesthesia was observed within 10 minutes. Experimenters were blinded to the randomized assignment of animals with respect to group allocation.