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Higher metabolic capacity in mice in comparison to rats during acclimation to chronic hypoxia
Author(s) -
Reyes Christian Arias,
Losantos Karen,
Soliz Jorge,
Joseph Vincent
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.551.4
Subject(s) - respirometer , hypoxia (environmental) , acclimatization , effects of high altitude on humans , metabolism , biology , oxygen , medicine , endocrinology , respirometry , respiration , chemistry , biochemistry , anatomy , ecology , organic chemistry
The aptitude of mammals to colonize high altitude (HA) environments is limited by their ability to tolerate decreased oxygen availability. While rats are not found under natural conditions above 2500 meters of altitude, mice are common in such habitats. Previous research in our lab showed that rats and mice display divergent physiological and molecular responses after acute (short‐term) exposure to hypoxia. As the response to hypoxia and metabolism control are tightly linked, in this work we aimed to identify the strategies underlying the metabolic response of mice and rats along the process of acclimation to short and long‐term hypoxia. Male FVB mice and Sprague – Dawley rats were exposed to hypoxia (12% O 2 ) for 0 hours (normoxic controls), 6 hours, 1, 7 and 21 days. During the last hour of the exposure, the whole‐body oxygen consumption (VO 2 ) and CO 2 production (VCO 2 ) were measured by indirect calorimetry. In following, samples of brain cortex were collected to evaluate the mitochondrial O 2 consumption rate with the high‐resolution respirometer Oxygraph‐2k (Oroboros Inc.). Our results in mice showed increased VO 2 and VCO 2 (25% and 41% compared to controls) starting at 7 days of exposure to hypoxia. At the cellular level, mitochondrial O 2 consumption in brain cortex increased after one day of hypoxia and then returned to control levels. A mild uncoupling was also observed in the cerebral mitochondria of mice. Contrastingly, no change was observed in rats. These results show that mice, are able to increase their aerobic metabolism during acclimatization to chronic hypoxia, while rats are not. Given that this phenotype is also present in other rodent species adapted to high altitude, our findings support hypothesis that mice, but not rats, are pre‐adapted to high altitude hypoxia due to early events in their phylogeographic history. Support or Funding Information This research is conducted with the funds granted by the Natural Sciences and Engineering Research Council of Canada. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .