Objective To observe the effect of electroacupuncture(EA)on incisional pain and expression of tumor necrosis factor-α(TNF-α)

interleukin-10(IL-10)and interleukin-4(IL-4)of cervical dorsal part of spinal cord in rats with incisional neck pain

so as to explore its analgesic mechanisms.Methods Eighty-four male SD rats were randomly divided into normal control

model

EA-Futu(LI18)and EA-Zusanli(ST36)-Yanglingquan(GB34

EA-ST36-GB34)groups(n=21 in each group). The incisional neck pain model was established by making a longitudinal incision along the bilateral cervical thyroid regions and repeated mechanical separation stimulation. For rats of the EA groups

EA(2 Hz/100 Hz

1 m A)was applied to bilateral LI18 or ST36-GB34 for 30 min/time during the surgery

and 20 and 44 h after surgery

respectively. The thermal pain threshold(TPT)of the incisional region was detected. The immunoactivity of TNF-αand IL-10 of the dorsal portion of the cervical spinal cord(C2—C5)was detected by immunofluorescence

and the expression of TNF-α

IL-10

IL-4 and IL-4 receptor(IL-4 R)m RNAs was determined by quantitative real-time PCR.Results Compared with the normal group

the TPT of the incisional area was significantly decreased at 4

24 and 48 h after neckincision(P<0. 05)

the levels of TNF-α m RNA

IL-10 m RNA and TNF-α IL-10 immunoactivity at 24 h were remarkably increased(P<0. 05)

and the expression of IL-4 R m RNA was considerably decreased at 24 h in the model group(P<0. 05). Following EA intervention

the TPT

and expression levels of IL-4 m RNA and IL-4 R m RNA were significantly increased at 24 h after surgery in the EA-LI18 group relevant to the model group(P<0. 05)

while the expression level of TNF-α(coexpressed with microgliacytes)in the EA-LI18 group

and TNF-α m RNA expression at 24 h in both EA-LI18 and EA-ST36-GB34 groups

as well as the expression of IL-10 and IL-10 m RNA at 24 h in both EA-LI18 and EA-ST36-GB34 groups were significantly decreased(P<0. 05). The effect of EA LI18 was significantly superior to that of EA ST36-GB34 in up-regulating TPT and expression of IL-4 m RNA and IL-4 R m RNA at 24 h(P<0. 05).Conclusion EA of LI18 has an analgesic effect in incisional neck pain rats

which may be related to its effect in down-regulating the expression of TNF-α

IL-10 and promoting IL-4/IL-4 R signaling in dorsal portions of the cervical spinal cord. The analgesic effect of EA LI18 is better than that of EA ST36-GB34.