Chronic constriction injury in rats

A neuropathic pain model of chronic constriction injury (CCI) described by Bennet and Xie [22] was applied. The day before surgery, rats were individually housed. Under 1.5% isofluorane anesthesia, the sciatic nerve of the left hind paw was exposed at the level of the middle of the thigh by dissection through biceps femoris. The nerve was freed of adhering tissue, and three loose ligatures, the first in the middle of the section exposed, were tied around it with approximately 3 mm spacing.

In order to test for a synergistic effect, we administered a combination of trazodone and gabapentin ineffective doses (trazodone 0.3 mg/kg, p.o. and gabapentin 3 mg/kg, i.p.) and examined the effects on mechanical hyperalgesia, weight bearing deficit, burrowing and nest construction behaviour. Doses were administered in 10 ml/kg body weight. Naive rats were used as positive control, while ligated rats receiving vehicle were used as negative control.