Objective To observe the effect of acupuncture on microglia polarization and inflammatory reaction in rats with cerebral ischemia-reperfusion injury(CIRI)

so as to explore its mechanisms underlying improvement of CIRI. Methods Thirty male SD rats were randomly divided into sham operation

model

and acupuncture groups

with 10 rats in each group. The CIRI model was established by occlusion of the middle cerebral artery(MCAO) for 1 h

followed by reperfusion. After modeling

rats in the acupuncture group received manual acupuncture stimulation of “Dazhui”(GV14)

“Baihui”(GV20)

“Shuigou”(GV26)

bilateral “Zusanli”(ST36) and “Fengchi”(GB20) by twirling the needles rapidly for 10 s/acupoint every 10 min

with the needles retained for 20 min. The treatment was conducted once daily for successive 7 days. The neurological function was evaluated according to Longa's method. The state of CIRI was observed after Nissl staining

and the expression levels of Iba-1

iNOS

Arg1

BDNF

GDNF and NeuN in the ischemic cortex tissue were detected by immunofluorescence staining. The contents of TNF-α

IL-6 and IL-10 in the ischemic tissue were assayed by ELISA. The protein expression levels of BDNF

GDNF

TLR4

MyD88 and NF-κB in the ischemic tissues were detected by Western blot. Results The neurological deficit score on the 24 h and 7

(th)

day was considerably higher in the model group than in the sham operation group(P

<

0.01)

and evidently lower on the 7(th) day was considerably higher in the model group than in the sham operation group(P

<

0.01)

and evidently lower on the 7

(th)

day in the acupuncture group than in the model group(P

<

0.01). The number of NeuN positive cells

the area of immunofluorescence dual labelling of Arg1

BDNF and GDNF positive staining

IL-10 content

BDNF and GDNF protein expressions were significantly decreased(P

<

0.01)

and the immunofluorescence dual labelling area of Iba-1 and iNOS

TNF-α and IL-6 contents

the pretein expression levels of TLR4

MyD88 and NF-κB considerably increased(P

<

0.01) in the model group relevant to the sham operation group. In contrast to the model group

the acupuncture group had a significant increase in the number of NeuN positive cells

the immunofluorescence dual labelling area of Arg1

BDNF and GDNF positive staining

IL-10 content

and BDNF and GDNF protein expressions(P

<

0.05

P

<

0.01)

and an evident decrease in Iba-1 and iNOS positive staining

contents of TNF-α and IL-6

and the protein expression levels of TLR4

MyD88 and NF-κB(P

<

0.01

P

<

0.05). Nissl staining showed a marked reduction in the number of neurons

the nucleus pyknosis and nissl bodies and loose arrangement of the neuronal cells in the model group

which was relatively milder in the acupuncture group. Conclusion Acupuncture intervention can improve neurological function in CIRI rats

which may be related to its effects in regulating the polarization of microglia

reducing inflammatory reaction and increasing the secretion of neurotrophic factors in the brain

inhibiting TLR4/MyD88/NF-κB signaling pathway.