Objective To observe the changes of N-methyl-D-aspartic acid(NMDA)receptor expression of spinal cord after electroacupuncture(EA)intervention in rats with chronic constrictive injury(CCI)of the sciatic nerve so as to reveal the mechanism underlying improvement of neuropathic pain.Methods Sixty male SD rats were randomly divided into sham operation(sham)group

CCI model group and EA group(n=20).CCI model was established by ligature of the right sciatic nerve with apiece of surgical chromic suture.For rats of the sham group

the right sciatic nerve was just isolated without ligature.The rats of the EA group were given with EA stimulation of"Weizhong"(BL 40)and"Huantiao"(GB 30)on the injured side at a frequency of 2Hz

electric current of 1-3mA for 30min(increasing 1mA every 10min).The treatment was conducted once a day from the11th day to the 20th day after modeling.NMDA receptor 2Bsubunit(NR 2B)protein and mRNA expression levels in the spinal cord were determined by immunohistochemistry

Western blot and reverse transcription(RT)-polymerase chain reaction(PCR)

respectively

and spinal NMDA receptor subunit 1(NR 1)protein and mRNA expression levels were measured by Western blot and RT-PCR

respectively.Results In comparison with the sham group

NR 1protein and mRNA expression levels of the model group in the spinal cord were considerably upregulated after CCI(P<0.01

P<0.05).In comparison with the model group NR 1protein and mRNA expression levels of the EA group in the spinal cord were evidently down-regulated(P<0.05).No significant changes of NR 2Bprotein and mRNA expression after CCI and EA stimulation were found after immunohistochemistry

Western blot and RT-PCR measurements(P>0.05).Conclusion EA intervention is effective in alleviating neuropathic pain in CCI rats

which may be closely related to its effects in lowering functional activity of NR 1protein and mRNA in the spinal cord.