Objective To observe the effect of electroacupuncture(EA) on ultrastructure of facial nerve and Schwann cells in facial nerve injury rabbits so as to explore its mechanism underlying improving facial palsy.Methods A total of 60 Japanese white rabbits were randomly assigned to normal control(normal

n=6)

sham-operation(sham

n=18)

model(n=18) and EA(n=18) groups.The facial nerve injury model was established by clamping the right facial nerve for 5 min by using a pair of forceps.EA(1.5 V

3 Hz/60 Hz) was applied to "Yifeng"(TE 17)-"Hegu"(LI 4)

and "Dicang"(ST 4)-"Jiache"(ST 6) on the affected side for 30 min

respectively

once daily for 3 weeks.Morphologic changes of the myelin sheath and Schwann cells of the facial nerve were observed by using electron microscope after 1

2 and 3 weeks' treatment.Results Compared with the normal control group

the number of the myelin sheaths and the thickness values of the facial nerve after treatment of 1

2 and 3 weeks in the model group were decreased significantly(P<0.01

P<0.05).While in comparison with the model group

the thickness value of the facial nerve 2 weeks after modeling in EA group was increased considerably(P<0.01).In the model group

there were many vacuoles in the cytoplasm of Schwann cells instead of organells in the facial nerve.In the sham group

the demyelination was milder than that of the model group

and majority of myelin sheaths showed integral structure after 2 and 3 weeks

being similar to the normal group.Compared with the model group

the extent of demyelination was less distinct

with rela-tively more abundant organells in the facial nerve of the EA group

especially after 1 week of treatment.Among the three time points in the EA group

demyelination was milder in the 1st week not in the other time points.In contrast

along with the continuous EA treatment

the situation became worse after 3 weeks of treatment in the EA group.Conclusion In the acute stage of facial nerve injury

EA intervention can play a positive effect on the repair of the nerve and Schwann cells.However

continuous 3-weeks' EA intervention may worsen the facial nerve injury.