Objective To observe the effect of electroacupuncture(EA) on the ocular surface inflammation and α7 nicotinic acetylcholine receptor(α7 nAChR)/nuclear factor kappa-B(NF-κB) p65 signal pathway in guinea pigs with dry eye

so as to explore its underlying mechanism. Methods A total of 32 male British tricolor short haired guinea pigs were randomized into blank control

model

EA and sham acupuncture groups

with 8 guinea pigs in each group. The dry eye model was established by subcutaneous injection of scopolamine hydrobromide solution(0.6 mg/0.2 mL each time

4 times a day for 10 days). Guinea pigs of the EA group was treated with EA at bilateral “Cuanzhu”(BL2) and “Taiyang”(HN5)

and manual acupuncture at bilateral “Jingming”(BL1)

“Sizhukong”(SJ23)

“Tongziliao”(GB1) for 15 min

once daily for 14 days. For animals of the sham acupuncture group

a blunt needle was used to prick the skin surface of the acupoints

the acupoint selection and stimulation time were the same as those in the EA group. Before and after modeling and after the intervention

the breakup time(BUT) of lacrimal film

sodium fluorescein coloring(Fl) state of corneal epithelium and phenol red thread(PRT) moist length were recorded for assessing the severity of dry eye. The density of activated immune cells around the corneal epithelial stromal cells was determined by corneal confocal microscopy. The contents of interleukin-4(IL-4)

IL-6

IL-10

tumor necrosis factor α(TNF-α) in the cornea and lacri-mal gland tissues were determined by ELISA

and the expression levels of α7 nAChR and NF-κB p65 in the cornea and lacrimal gland were detected by immunohistochemistry and Western blot

separately. Results Compared with the blank control group

the corneal Fl

density of activated immune cells of corneal epithelium

contents of IL-6

IL-10 and TNF-α in both corneal and lacrimal gland tissues

NF-κB p65 cell positive rate and protein expression of lacrimal gland and corneal tissues were significantly increased(P<0.01

P<0.05)

while the BUT

PRT and lacrimal gland α7 nAChR cell positive rate considerably decreased(P<0.01) in the model group. In comparison with the model group

the level of corneal Fl

density of the activated immune cells of corneal epithelium

contents of corneal and lacrimal IL-6 and TNF-α

and corneal and lacrimal NF-κB p65 cell positive rates and protein expressions were remarkably down-regulated in the EA group(P<0.01

P<0.05)

rather than in the sham acupuncture group(P>0.05) except content of corneal IL-10

lacrimal NF-κB p65 cell positive rate and lacrimal α7 nAChR protein expression

whereas the levels of BUT

PRT

corneal and lacrimal IL-10 and corneal and lacrimal α7 nAChR cell positive rates and protein expressions significantly up-regulated in the EA group(P<0.01

P<0.05)

rather than in the sham acupuncture group(P>0.05) except corneal TNF-α and corneal NF-κB p65 protein expression. Conclusion EA can improve corneal and lacrimal function in dry eye guinea pigs

which may be associated with its actions in increasing the expression of α7 nAChR

inhibiting the nuclear translocation of NF-κB

and reducing the activated immune cells and inflammatory reaction.