Abstract: OBJECTIVE: To investigate the role of spinal prostaglandin E_2(PGE_2) in electroacupuncture(EA) analgesia and assess the theoretical basis for selection of acupoints in the treatment of neuropathic pain.METHODS: A rat model of neuropathic pain was established. Rats were randomly divided into normal,model, sham, EA 1, EA 2, and EA 3 groups. In EA 1group, the rats were needled at bilateral L5 Jiaji(EX-B2), Dachangshu(BL 25), Weizhong(BL 40) and Kunlun(BL 60). In EA 2 group, the rats were needled at bilateral Weizhong(BL 40) and Kunlun(BL60). In EA 3 group, the rats were needled at bilateral L5 Jiaji(EX-B2) and Dachangshu(BL 25). EA stimulation was administered once daily over 7 days. Motor function and thermal withdrawal latencies were evaluated at 1 day preoperatively and at 3, 5, and 7 days postoperatively. After 7 days of intervention,enzyme-linked immunosorbnent assay(ELISA) was used to quantify the expression of the spinal PGE_2.RESULTS: Rats in the model group exhibited evident hyperalgesia in responses to thermal withdrawal latencies compared with those in the control group(P < 0.01), and EA reversed thermal withdrawal latencies(P < 0.01). The expression level of the spinal PGE_2 was significantly higher in the model group than that in the control group and was reversed by EA(P < 0.01; P < 0.05).CONCLUSION: The effect of EA on neuropathic pain might alleviate the hyperalgesia state by an inhibition of local prostaglandin E_2 secretion.

Key words: Electroacupuncture, Neuralgia, Dinoprostone, Acupuncture analgesia, Spinal cord, Hyperalgesia