Effect of electroacupuncture on E-prostanoid 2 expression in the spinal cord in rats with neuropathic pain

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.