Abstract:
Naked mole-rats are among the most hypoxia-tolerant mammals. During hypoxia, their body
temperature (Tb) decreases via unknown mechanisms to conserve energy. In small mammals,
non-shivering thermogenesis in brown adipose tissue (BAT) is critical to Tb regulation;
therefore, we hypothesize that hypoxia decreases naked mole-rat BAT thermogenesis. To
test this, we measure changes in Tb during normoxia and hypoxia (7% O2; 1–3 h). We report
that interscapular thermogenesis is high in normoxia but ceases during hypoxia, and Tb
decreases. Furthermore, in BAT from animals treated in hypoxia, UCP1 and mitochondrial
complexes I-V protein expression rapidly decrease, while mitochondria undergo fission, and
apoptosis and mitophagy are inhibited. Finally, UCP1 expression decreases in hypoxia in three
other social African mole-rat species, but not a solitary species. These findings suggest that
the ability to rapidly down-regulate thermogenesis to conserve oxygen in hypoxia may have
evolved preferentially in social species.
