[Effect of electroacupuncture intervention on N-methyl-D-aspartic acid receptor expression in spinal cord in rats with chronic constrictive injury of the sciatic nerve].

UNLABELLED: 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 a piece 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 2 Hz, electric current of 1-3 mA for 30 min (increasing 1 mA every 10 min). The treatment was conducted once a day from the 11th day to the 20th day after modeling. NMDA receptor 2 B subunit (NR 2 B) 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 1 protein 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 1 protein and mRNA expression levels of the EA group in the spinal cord were evidently down-regulated (P < 0.05). No significant changes of NR 2 B protein 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 1 protein and mRNA in the spinal cord.