Dynamics of Tissue-Specific Changes in AMPK Concentration during Adaptation to Hypobaric Hypoxia

Introduction. AMP-activated protein kinase (AMPK) plays an essential role in the adaptation of cellular metabolism to hypoxia. At the same time, the severity and intensity of AMPK-dependent adaptive mechanisms depend on the duration and strength of the hypoxic stimulus, which can be used during hypoxic training. 

The purpose of the study was to dynamically evaluate the tissue-specific change in AMPK concentration under conditions of short-term hypobaric hypoxia in Balb/c mice. 

Materials and Methods. Short-term hypobaric hypoxia was modeled by placing animals in a pressure chamber with air with oxygen saturation of 14 % (equivalent to an altitude of 4000 m above sea level). The duration of hypoxia was 120 sec., 240 sec., 360 sec., 480 sec., 600 sec. and 720 sec. Next, blood and internal organs (liver, skeletal muscles, brain, subcutaneous adipose tissue) were taken from mice to obtain serum and supernatants, respectively, in which the concentration of AMPK was assessed. The AMPK content was determined by solid-phase enzyme immunoassay. 

Results. Under hypobaric hypoxia duration 120 sec. the content of AMPK in the blood serum was reduced, but it leads to a change in the concentration of the enzyme in the supernatants of internal organs. Subsequently, it was shown that the content of AMPK is strongly correlated with the time of hypoxia (for blood serum R2 = 0.7519; liver R2 = 0.8873; subcutaneous fat R2 = 0.8479; skeletal muscles R2 = 0.9406; brain R2 = 0.8516). The most significant changes were noted with a duration of hypobaric hypoxia of 720 seconds, when the AMPK content increased relative to the intact group of mice in the adipose tissue supernatant by 106.0 %; liver supernatant — 115.2 %; skeletal muscles — 96.0 % and brain — 155.2 % (all parameters p < 0.05). 

Conclusion. Short-term hypobaric hypoxia lasting from 4 to 12 minutes. It promotes an increase in AMPK levels in the brain, skeletal muscles, liver and subcutaneous adipose tissue, while the AMPK content in the blood serum significantly decreased. The results obtained can be used in studying the mechanisms of body adaptation to hypoxia conditions and optimizing the hypoxic training regime, both at the preclinical and clinical stages of research work.

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