Objective To observe the effects of transcutaneous auricular vagus nerve stimulation(taVNS) on the motor function and the expression of glial fibrillary acidic protein(GFAP) and microtubule associated protein 2(MAP2) in cerebral ischemic penumbra of rats with middle cerebral artery occlusion(MCAO) and explore the mechanism of taVNS in the improvement of motor function in MCAO rats. Methods A total of 48 male SD rats were randomized into a sham-operation group

a model group

a transcutaneous auricular non-vagus nerve stimulation(tnVNS) group and a taVNS group

with 12 rats in each group. The suture-occluded method was adopted to prepare MCAO rat model. The auricular rim was stimulated in the tnVNS group and the concha stimulated in the taVNS group

2 mA in intensity

10 Hz in frequency

30 min each time

once a day

for 14 days consecutively. The nerve functional assessment was recorded in each group. The expressions of nicotinic acetylcholine receptor(α7 nAchR) in the cerebral ischemic penumbra and the spleen were detected by using Western blot. With the immunofluorescence

the expressions of GFAP and MAP2 were detected. Results After modeling

compared with the sham-operation group

the nerve functional score was increased in the model group

the tnVNS group and the taVNS group(P<0.01)

suggesting the success of modeling. After treatment

the score was increased in the model group(P<0.01) as compared with the sham-operation group. Compared with the model group

the neurological deficit score was reduced in the taVNS group(P<0.01). Compared with the sham-operation group

GFAP expression was increased and MAP2 expression was reduced remarkably in the cerebral ischemic penumbra in the model group(P<0.05). In comparison with the model group

GFAP expression was reduced

while MAP2 expression was increased remarkably in the cerebral ischemic penumbra in the taVNS group(P<0.05). There were no significant differences in the abovementioned indexes between the model group and tnVNS group(P>0.05). The differences in the expression of α7 nAchR in the cerebral ischemic penumbra and the spleen had no statistical significance among groups(P>0.05). Conclusion TaVNS is effective on neuroprotection in MCAO rats

which may be related to its function of inhibition of GFAP expression and promotion of MAP2 expression in the ischemic penumbra.