Objective To explore the mechanism of electroacupuncture(EA)in accelerating the aggregation of microglia and promoting the remyelination at the location of demyelination.Methods C57BL/6 mice were randomly divided into4 groups:normal

control

model(LPC)and LPC+EA.The demyelination model was established by microinjection of Lysolecithin(LPC

1μL)into the left corpus callosum.EA(2 Hz/15 Hz

2-4 mA)was applied to "Baihui" (GV20)and "Zhiyang" (GV9)for 30 min

once daily for 3 days

then

once every other day for 18 days.Immuno-fluorescence staining was used to observe the expression of myelin basic protein(MBP)and Axl tyrosine kinase receptor(Axl)

Iba1 and numbers of Olig2-positive oligodendrocytes in the corpus callosum.Western blot was employed to detect the expression of MBP in the corpus callosum

and Oil Red O staining was used to observe changes of number of myelin pieces.Results Following modeling

the expression levels of MBP on day 5 and 10 after modeling were significantly decreased(P<0.05

P<0.01)

Iba1 expression and Olig2-positive oligodendrocyte numbers on day 10 apparently increased(P<0.001

P<0.01).On day 21 after modeling

the levels of the above mentioned indexes returned to normal.After EA intervention

the levels of MBP expression on day 5 and 10

Axl

Iba1 protein expression and Olig2-positive oligodendrocyte numbers on day 5 were markedly increased(P<0.001

P<0.01

P<0.05)

while Iba1 expression on day 10 was considerably decreased in comparison with the model group(P<0.01).Oil Red O staining showed that on day 5 after modeling

the number of red lipid droplets were obviously increased in the corpus callosum tissue on the injection side

and apparently reduced in the EA group

suggesting a clearance of the accumulated myelin fragments by EA.Conclusion EA intervention may reduce myelin debris and promote the aggregation of microglial cells and oligodendrocytes to the injured site

accelerate the myelin regeneration and up-regulate the expression of MBP and Axl of corpus callosum in demyelination mice.