Objective To observe the effects of electroacupuncture(EA) at “Fengchi”(GB20) on the ethology

microglia activation and P2 X7 receptor(P2 X7 R) expression in the periaqueductal gray(PAG) in recurrent migraine rat model

so as to explore the underlying mechanism of EA reducing central sensitization of migraine. Methods Thirty-six male SD rats were randomly divided into control

model and EA groups

with 12 rats in each group. Recurrent migraine model was induced using repea-ted dural electrical stimulation once another day(the 1

(st)

3(st)

3

(rd)

5(rd)

5

(th)

7(th)

7

(th)

and 9(th) and 9

(th)

days)

for a total of 5 times; rats in the EA group received EA treatment(2 Hz/15 Hz

0.8—1 mA) at GB20 after dural electrical stimulation

for 10 min every time

once a day for 9 days; rats in the control group only received electrode placement. The facial and hindpaw mechanical withdrawal threshold was detected by using an electronic von-Frey on the 0(th) days)

for a total of 5 times; rats in the EA group received EA treatment(2 Hz/15 Hz

0.8—1 mA) at GB20 after dural electrical stimulation

for 10 min every time

once a day for 9 days; rats in the control group only received electrode placement. The facial and hindpaw mechanical withdrawal threshold was detected by using an electronic von-Frey on the 0

(th)

(baseline)

2(th)(baseline)

2

(nd)

4(nd)

4

(th)

6(th)

6

(th)

and 8(th)

and 8

(th)

days. Microglia activation in the PAG was evaluated by using immunofluorescence staining to detect the number of ionized calcium binding adaptor molecule-1(Iba-1)-labeled microglia. Expression levels of microglia marker Iba-1

inflammatory factor interleukin(IL)-1β and P2 X7 R were detected by Western blot. Results Compared with the control group

the facial and hindpaw mechanical withdrawal threshold of rats were significantly reduced on the 2(th) days. Microglia activation in the PAG was evaluated by using immunofluorescence staining to detect the number of ionized calcium binding adaptor molecule-1(Iba-1)-labeled microglia. Expression levels of microglia marker Iba-1

inflammatory factor interleukin(IL)-1β and P2 X7 R were detected by Western blot. Results Compared with the control group

the facial and hindpaw mechanical withdrawal threshold of rats were significantly reduced on the 2

(nd)

4(nd)

4

(th)

6(th)

6

(th)

and 8(th)

and 8

(th)

days(P

<

0.01

P

<

0.001); the microglia in the PAG area were significantly activated

with the number of Iba-1-positive microglia

and the expression levels of Iba-1

IL-1β and P2 X7 R proteins significant increased(P

<

0.001

P

<

0.05) in the model group. Compared with the model group

the facial and hindpaw mechanical withdrawal threshold of rats were significantly increased on the 4(th) days(P

<

0.01

P

<

0.001); the microglia in the PAG area were significantly activated

with the number of Iba-1-positive microglia

and the expression levels of Iba-1

IL-1β and P2 X7 R proteins significant increased(P

<

0.001

P

<

0.05) in the model group. Compared with the model group

the facial and hindpaw mechanical withdrawal threshold of rats were significantly increased on the 4

(th)

6(th)

6

(th)

and 8(th)

and 8

(th)

days(P

<

0.05

P

<

0.001

P

<

0.01)

and the above indicators were significantly reversed(P

<

0.05) in the EA group. Conclusion EA at GB20 can significantly improve facial and hindpaw mechanical withdrawal threshold of migraine rats

and its possible mechanism may be related to inhibiting microglia activation mediated by P2 X7 R in the PAG.