The increase of substance P expression in dorsal horn of spinal cord in rats with chronic constriction nerve injury

Objective To observe the expressive variety of substance P in the dorsal horn of spinal cord on neuropathic pain by chronic constriction injury(CCI).Methods Sixty male Sprague-Dawley rats were randomly divided into two groups:CCI group,control group.Record the responsiveness to mechanical and thermal stimuli before and after sciatic nerve constriction injury.Immuno-histochemistry technique was used to measure the expression of substance P in the dorsal horn of spinal cord at 3th,7th,14th,28th days following sciatic nerve constriction injury.Results The rats' responsiveness to mechanical and thermal stimuli and pain behavior were significantly increased on postoperative days after sciatic nerve ligation compared with preoperative(P0.05).The relative expression level of substance P was obviously increased at 3 day in the dorsal horn of spinal cord after sciatic nerve constriction injury compared with preoperative(P0.05).In group A increase in substance P expression in the dorsal horn of spinal cord was obviously increased compared with groupB(P0.05).Conclusions The CCI rats' sensitivity to thermal and mechanical stimuli was significantly increased following sciatic nerve constriction injury.This could be related to the increase of substance P expression in the dorsal horn of spinal cord.