[Effect of electroacupuncture on pain threshold and spinal NR2B subunit expression in a rat model of neuropathic pain].

ABSTRACT

OBJECTIVE: To observe the effect of electroacupuncture (EA) on pain threshold and spinal NR2B subunit expression in a rat model of neuropathic pain due to chronic compression injury (CCI) of the sciatic nerve and explore the analgesic mechanism of EA. METHODS: Male SD rats weighing 200-280 g were randomly divided into 4 groups (n=10), namely the sham-operated group, CCI group, EA+CCI group, and sham EA+CCI group. All the rats underwent tests of the mechanical withdrawal threshold and thermal threshold. On day 13 after the surgery, all the rats were decapitated to collect the L4-6 segments of the spinal cord to examine NR2B expression using Western blotting. RESULTS: The postoperative mechanical withdrawal threshold and thermal threshold were significantly lowered in CCI, EA+CCI and sham EA+CCI groups as compared to those before the surgery (P<0.05). EA obviously alleviated the hypersensitivity in the rats with CCI and inhibited spinal NR2B expressions (P<0.05). No significant differences were found in the mechanical withdrawal threshold, thermal threshold or spinal NR2B subunit expression between CCI group and sham EA+CCI group (P>0.05). CONCLUSION: EA may alleviate neuropathic hypersensitivity partially by inhibiting NR2B expression in the spinal cord of rats with neuropathic pain resulting from CCI of the sciatic nerve.