Objective:

2

To explore the protective effect of bloodletting acupuncture at twelve Jing-well points on hand (BAJP) on acute hypobaric hypoxia (AHH)-induced brain injury in rats and its possible mechanisms.

Methods:

2

Seventy-five Sprague Dawley rats were divided into 5 groups by a random number table (

n

=15)

including control

model

BAJP

BAJP+3-methyladenine (3-MA)

and bloodletting acupuncture at non-acupoint (BANA

tail tip blooding) groups. After 7-day pre-treatment

AHH models were established using hypobaric oxygen chambers. The levels of S100B

glial fibrillary acidic protein (GFAP)

superoxide dismutase (SOD)

and malondialdehyde (MDA) in serum were measured by enzyme-linked immunosorbent assay. Hematoxylin-eosin staining and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method were used to assess hippocampal histopathology and apoptosis. Transmission electron microscopy assay was used to observe mitochondrial damage and autophagosomes in hippocampal tissues. Flow cytometry was used to detect mitochondrial membrane potential (MMP). The mitochondrial respiratory chain complexes Ⅰ

Ⅲ and Ⅳ activities and ATPase in hippocampal tissue were evaluated

respectively. Western blot analysis was used to detect the protein expressions of Beclin1

autophagy protein 5 (ATG5)

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

phosphatase and tensin homolog induced kinase 1 (PINK1)

and Parkin in hippocampal tissues. The mRNA expressions of Beclin1

ATG5 and LC3-Ⅱ were analyzed by quantitative real-time polymerase chain reaction.

Results:

2

BAJP treatment reduced hippocampal tissue injury and inhibited hippocampal cell apoptosis in AHH rats. BAJP reduced oxidative stress by decreasing S100B

GFAP and MDA levels and increasing SOD level in the serum of AHH rats (

P

<

0.05 or

P

<

0.01). Then

BAJP increased MMP

the mitochondrial respiratory chain complexes Ⅰ

Ⅲ and Ⅳ activities

and the mitochondrial ATPase activity in AHH rats (all

P

<

0.01). BAJP improved mitochondrial swelling and increased the autophagosome number in hippocampal tissue of AHH rats. Moreover

BAJP treatment increased the protein and mRNA expressions of Beclin1 and ATG5 and LC3-Ⅱ/LC3-Ⅰ ratio in AHH rats (all

P

<

0.01) and activated the PINK1/Parkin pathway (

P

<

0.01). Finally

3-MA attenuated the therapeutic effect of BAJP on AHH rats (

P

<

0.05 or

P

<

0.01).

Conclusion:

2

BAJP was an effective treatment for AHH-induced brain injury

and the mechanism might be through reducing hippocampal tissue injury via increasing the PINK1/Parkin pathway and enhancement of mitochondrial autophagy.