Objective

2

To observe the effects of electroacupuncture (EA) at "Shenting" (GV24) and "Baihui" (GV20) on mitochondrial autophagy in hippocampal neurons and silent information regulator sirtuin 1 (Sirt1)/forkhead box O3 (FOXO3)/PTEN-inducible kinase 1 (PINK1)/Parkin pathway in rats with learning-memory impairment after cerebral ischemia reperfusion injury.

Methods

2

A total of 35 male SD rats were randomly divided into a sham operation group (9 rats) and a modeling group (26 rats). In the modeling group

middle cerebral artery occlusion method was used to establish the middle cerebral artery ischemia-reperfusion (MCAO/R) model

and 18 rats of successful modeling were randomly divided into a model group and an EA group

9 rats in each one. EA was applied at "Shenting" (GV24) and "Baihui" (GV20) in the EA group

30 min a time

once a day for 14 days. After modeling and on 7th and 14th days of intervention

neurologic deficit score was observed; the learning-memory ability was detected by Morris water maze test; the morphology of neurons in CA1 area of hippocampus was detected by Nissl staining; the mitochondrial morphology was observed by transmission electron microscopy; the protein expression of Beclin-1

microtubule-associated protein 1 light chain 3B (LC3B)

P62

Sitrt1

FOXO3

PINK1 and Parkin was detected by Western blot.

Results

2

After modeling

the neurologic deficit scores in the model group and the EA group were higher than that in the sham operation group (

P

<

0.001); on 7th and 14th days of intervention

the neurologic deficit scores in the model group were higher than those in the sham operation group (

P

<

0.001)

the neurologic deficit scores in the EA group were lower than those in the model group (

P

<

0.05

P

<

0.01). After modeling

the escape latency in the model group and the EA group was prolonged compared with that in the sham operation group (

P

<

0.001); on 9th-13th days of intervention

the escape latency in the model group was prolonged compared with that in the sham operation group (

P

<

0.001)

the escape latency in the EA group was shortened compared with that in the model group (

P

<

0.05

P

<

0.01

P

<

0.001). The number of crossing plateau in the model group was less than that in the sham operation group (

P

<

0.001); the number of crossing plateau in the EA group was more than that in the model group (

P

<

0.05). In the model group

in CA1 area of hippocampus

the number of neurons was less

with sparse arrangement

nuclear fixation

deep cytoplasmic staining

and reduction of Nissl substance; the morphology of mitochondrion was swollen

membrane structure was fragmented

a

nd autophagic lysosomes were formed. Compared with the model group

in the EA group

in CA1 area of hippocampus

the number of neurons was increased

the number of cells of abnormal morphology was decreased

and the number of Nissl substance was increased; the morphology of mitochondrion was more intact and the number of autophagic lysosomes was increased. Compared with the sham operation group

in the model group

the protein expression of Beclin-1

FOXO3

PINK1

Parkin and the LC3BⅡ/Ⅰ ratio in hippocampus were increased (

P

<

0.01

P

<

0.001)

while the protein expression of P62 was decreased (

P

<

0.05). Compared with the model group

in the EA group

the protein expression of Beclin-1

Sirt1

FOXO3

PINK1

Parkin and the LC3BⅡ/Ⅰratio in hippocampus were increased (

P

<

0.001

P

<

0.01)

while the protein expression of P62 was decreased (

P

<

0.001).

Conclusion

2

EA at "Shenting" (GV24) and "Baihui" (GV20) can relieve the symptoms of neurological deficits and improve the learning-memory ability in MCAO/R rats

its mechanism may relate to the modulation of Sirt1/FOXO3/PINK1/Parkin pathway and the enhancement of mitochondrial autophagy.