Objective      To detect adenosine monophosphate-activated protein kinase (AMPK) activation level in chronic hypoxic myocardial tissues

and explore the protective effect of phosphorylated AMPK (p-AMPK) to the currival of  chr

onic hypoxic myocardial cells.       Methods      Twenty-four children with congenital heart disease

including 12 cases of cyanotic type and type 12 cases of non-cyanotic

were selected from Xinqiao Hospital of Third Military Medical University in 2013

and the myocardial tissues of right ventricular outflow tract were taken out as samples. Twenty-four SD male rats were divided into normoxic control group and hypoxia group. The hypoxia group was placed in a low-pressure tank (simulated altitude of 5 000 m

405 mmHg)

while the normoxic control group received normal feeding. After feeding for 28 d

the rats were executed and the hearts were immediately taken out to isolate the right ventricular tissues. Western blotting was used to detect the activation level of AMPK in the hypoxic myocardial tissues of the children and rats. H9c2 myocardial cells were divided into normoxic control group

hypoxia group

blocking group and activation group. Except the normoxic control group

other three groups were placed in a hypoxia incubator (94% N

2

5% CO

2

1% O

2

) for 3 d to establish H9c2 chronic hypoxia cell models

while the normoxic control group was cultured in a cell culture box for 3 d in comparison. AMPK-specific blocker Compound C and activator AICAR were added to the blocking group and the activation group

respectively. Western blotting was employed to detect the expression of p-AMPK

and flow cytometry and TUNEL assay were adopted to detect myocardial cell apoptosis. The cell nucleus shape was observed by Hoechst staining

and myocardial cell death was measured with LDH test kit.       Results      Western blot results showed that compared with the normoxian group

the p-AMPK/AMPK ratio in the hypoxic myocardial tissue was increased significantly. Compared with the hypoxia group

the apoptosis cell percentage

TUNEL-positive cell percentage (P0.05)

abnormal nuclear scale (P0.01)

and cell mortality (P0.01) of the blocking group were increased significantly. Compared with the hypoxi

a group

the apoptosis cell percentage

TUNEL-positive cell percentage (P0.05)

abnormal nuclear scale (P0.05)

and cell mortality (P0.05) of the AMPK activation group were decreased.       Conclusion      Under the condition of chronic hypoxia

AMPK protein phosphorylation level is enhanced

and p-AMPK provides a certain protective effect to myocardial cells in chronic hypoxia adaptation.