Department of Biology, University of Ottawa, Ottawa, ON, Canada.
Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
Nat Commun. 2021 Nov 23;12(1):6801. doi: 10.1038/s41467-021-27170-2.
Naked mole-rats are among the most hypoxia-tolerant mammals. During hypoxia, their body temperature (T) decreases via unknown mechanisms to conserve energy. In small mammals, non-shivering thermogenesis in brown adipose tissue (BAT) is critical to T regulation; therefore, we hypothesize that hypoxia decreases naked mole-rat BAT thermogenesis. To test this, we measure changes in T during normoxia and hypoxia (7% O; 1-3 h). We report that interscapular thermogenesis is high in normoxia but ceases during hypoxia, and T 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.
裸鼹鼠是对缺氧最耐受的哺乳动物之一。在缺氧环境下，它们的体温（T）通过未知机制下降以节省能量。在小型哺乳动物中，棕色脂肪组织（BAT）的非颤抖产热对于 T 调节至关重要；因此，我们假设缺氧会降低裸鼹鼠 BAT 的产热。为了验证这一点，我们在常氧和缺氧（7% O；1-3 h）条件下测量 T 的变化。我们报告说，肩胛间的产热在常氧下很高，但在缺氧下停止，T 下降。此外，在缺氧处理的动物的 BAT 中，UCP1 和线粒体复合物 I-V 蛋白表达迅速下降，同时线粒体发生裂变，凋亡和线粒体自噬受到抑制。最后，在另外三种社会性非洲鼹鼠物种中，UCP1 的表达在缺氧时下降，但在独居物种中则不会。这些发现表明，在缺氧环境中快速下调产热以节省氧气的能力可能优先在社会性物种中进化。
