ObjectiveTo explore the involvement of miR-34 a in cerebral cortex mediated anti-hyperalgesic effect of electroacupuncture(EA) in mice with neuropathic pain induced by chronic constriction injury(CCI) of sciatic nerve

so as to reveal its mechanisms underlying improvement of neuropathic pain.MethodsA total of 75 male C57 BL/6 mice were equally randomized into 3 groups:sham

CCI model and CCI+EA(n=25 in each group). Mice of the sham group received simple separation of the right sciatic nerve without ligation. The CCI model was established by liagation of the right sciatic nerve. EA(2 Hz/15 Hz

1 mA)was applied to bilateral"Zusanli"(ST36)and"Sanyinjiao"(SP9)for 30 min

once every other day. The mechanical and thermal pain threshold of the bilateral hind-paws was detected at the 3 rd

5 th and 7 thday after modeling

and the expression of miR-34 a of bilateral cerebral cortex tissues and that of p53 protein of the left cerebral cortex were determined by using quantitive real time PCR and Western blot

respectively.ResultsThe mechnical paw withdrawal frequency were significantly higher and the thermal paw withdrawal latencies(PWLs)were significantly shorter at the affected hind-limb(rather than at the healthy hind limb)on day 3

5 and 7 in the CCI model group than those in the sham group(P<0. 05)

and considerably reversed at the affected hind-limb(rather than at the healthy hind limb)in the EA group than in the CCI model group(P<0. 05)

suggesting an analgesic effect of EA intervention. After modeling

the expression levels of miR-34 a and p53 on day 3

5 and 7 were significantly up-regulated in the left cerebral cortex tissue(rather than in the right cerebral cortex)of the CCI model group in comparison with the sham group(P<0. 05). After EA intervention

the up-regulated expression levels of miR-34 a and p53 in the left cerebral cortex tissue(rather than in the right cerebral cortex)were obviously suppressed in the EA group relevant to the CCI model group(P<0. 05).ConclusionEA stimulation of ST36 and SP9 can down-regulate the expression of miR-34 a and p53 in the contra-lateral cerebral cortex tissue of the CCI mice

which may contribute to its anti-hyperalgesic effect.