2.4. The Neuropathic Pain Model [13] (CCI)

Rats (n = 42) were anaesthetized with pentobarbital sodium (3%, 40 mg/kg, i.p., reinforced if necessary). The rats were then positioned in a stereotaxic frame. The sciatic nerve was exposed at the level of the middle of the thigh by blunt dissection through biceps femoris [14]. The bifurcated anterior nerve part of the sciatic nerve was tied (using 4.0 sutures) under a dissecting microscope and performed 4 times at intervals of about 1 mm, and a little twitch in the operated hindlimb was obtained, while rats (n = 7) in the sham group were subjected to all of these procedures but were not subjected to CCI. Then, gentamicin (2 ml, 10 mg/ml, i.m.) was given after the suture of the wound. After the surgery, sustained tactile and thermal hypersensitivity in the injured hind paw developed in each animal.