Abstract: OBJECTIVE: To observe the effect of electroacupuncture(EA) treatment on the expression of E-prostanoid 2(EP2) in the spinal cord using a rat model of neuropathic pain, and to examine the effect of different acupuncture prescriptions.METHODS: Rats were randomly divided into six groups: a normal group, model group, sham group,EA 1 group(distal-proximal acupoints), EA 2 group(proximal acupoints), and EA 3 group(distal acupoints). Rats in the EA groups were treated for20 min, once daily for 7 days. The mechanical withdrawal threshold was evaluated at 1 day preoperatively and at 3, 5, and 7 days postoperatively. At 7days postoperatively, hematoxylin-eosin(HE) staining was used to investigate spinal morphological changes. Spinal EP2 messenger ribonucleic acid(m RNA) was detected using reverse-transcription polymerase chain reaction.RESULTS: After the EA treatment, the mechanical withdrawal threshold was up-regulated compared with the model group(P < 0.05). The expression of EP2 m RNA was up-regulated in the spinal cord on day 7 after surgery(P < 0.05). EA stimulation tended to down-regulate EP2 m RNA expression compared with the model group(P > 0.05). The EA 1and EA 2 groups showed a larger treatment effect than the EA 3 group. The HE results showed that EA can improve spinal histomorphology induced by neuropathic pain.CONCLUSION: EA had a strong analgesic and anti-inflammatory effect. The therapeutic effect of EA on the down-regulation of spinal EP2 m RNA expression may be greater when either local acupoints or a distal-proximal combination of acupoints are used than when distal points are used.

Key words: Neuropathic pain, Electroacupuncture, Nucleus pulposus, E-prostanoid 2, Spinal cord