Objective To observe the effect of electroacupuncture(EA) on ocular surface sensory neuralgia and the expression of P2 X_3 receptor(P2 X_3R) and protein kinase C(PKC)in cornea and trigeminal ganglion(TG) in dry eye disease(DED) guinea pigs

so as to explore its mechanism underlying improvement of ocular surface sensory neuralgia in DED. Methods Male British tricolor short haired guinea pigs were randomly divided into control

model

medication(pranoprofen)

EA and sham acupuncture groups

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

once daily) for 10 d. Guinea pigs in the medication group were treated by applying pranoprofen eye drops to eyes

1 drop for one eye each time

three times a day. Guinea pigs of the EA group received EA stimulation(4 Hz/20 Hz

1 mA) of bilateral “Cuanzhu”(BL2) and “Taiyang”(HN5) and acupuncture at “Jingming”(BL1) “Sizhukong”(TE23)

“Tongziliao”(GB1) for 15 min

once a day. Guinea pigs in the sham acupuncture group received blunt stimu-lation at the surface of the same acupoint with the tip of the acupuncture needle

once a day. All the treatments were conducted for 14 d. The corneal epithelium fluorescein staining score(0-3 points) was given according to the number of fluorescence-positive dots and flake-like coloration

the corneal mechanical perception thread(CMPT) detected using a corneal perception meter

and the palpebral fissure height measured. The number of sensory neurons in the cornea and TG was determined by using cholera toxin subunit B conjugated with Alexa Fluor 488 fluorescence labelling

and the expression levels of P2 X_3R and PKC in the cornea and TG detected by using immunohistochemistry and Western blot

separately. Results Compared with the control group

the corneal fluorescein staining score

immunoactivity and expression of P2 X_3R proteins in both cornea and TG

PKC proteins in TG were significantly increased(P<0.01)

whereas the CMPT and the height of palpebral fissure and the number of TG neurons significantly decreased in the model group(P<0.05

P<0.01). In comparison with the model group

the fluorescein staining score in the medication and EA groups

the immunoactivity and expression of P2 X_3R in cornea and TG in the EA group

and that of TG PKC in the EA group and the sham acupuncture groups were significantly decreased(P<0.05

P<0.01)

while the height of palpebral fissure and CMPT after EA and the number of labelling TG sensory neurons were remarkably increased in the EA group(P<0.01) rather than in the medication and sham acupuncture groups(P>0.05). Conclusion EA can alleviate the damage of corneal epithelium and sensory neurons in dry eye model guinea pigs

which may be related to its functions in down-regu-lating the expression of P2 X_3R and PKC in the cornea and TG.