Objective: To investigate the effect of electroacupuncture(EA)on spinal interleukin-6(IL-6) protein expression in neuropathic pain rats.Methods: Twenty-four adult SD rats were evenly and randomly divided into sham-operation group

model group and EA group.Chronic constrictive injury(CCI) model was established by ligating the sciatic nerve with catgut under anesthesia(10% chloral hydrate

300 mg/kg).EA(2 Hz

1 mA) was applied to "Weizhong"(BL 40) and "Huantiao"(GB 30) for 30 min

once on the 1

s

t

4st

4

t

h and 7th and 7

t

h day after operation separately.The mechanical(von Frey filaments) and thermal(heat radiation) pain thresholds were measured before operation and on the 7th day after operation separately.The mechanical(von Frey filaments) and thermal(heat radiation) pain thresholds were measured before operation and on the 7

t

h day after the operation.The expression of IL-6 in the spinal cord(L_4-5) tissues was assayed by immunohistochemical technique.Results: Before operation

no significant differences were found among the 3 groups in both mechanical pain threshold and thermal pain threshold of the bilateral hind-limbs(P

>

0.05).In comparison with sham-operation group

after CCI

both the mechanical and thermal pain thresholds of model group on the affected hind-limb lowered significantly

appearing mechanical allodynia and thermal hyperalgesia.Compared with model group

the mechanical and thermal pain thresholds of EA group increased significantly after EA(P

<

0.05).Correspondingly

the average optical density value of IL-6 immunoreactive(IR) positive cells in the ipsilateral spinal dorsal horn of model group was significantly higher than that of sham-operation group and EA group(P

<

0.05).It indicated that EA could markedly suppress CCI-induced allodynia and hyperalgesia and increase of IL-6 expression in the spinal cord.Conclusion: EA analgesia may be related to its resultant downregulation of IL-6 expression in the dorsal horn of the spinal cord in neuropathic pain rats.