Markussen Fredrik A F, Melum Vebjørn J, Bothorel Béatrice, Hazlerigg David G, Simonneaux Valérie, Wood Shona H
Arctic Chronobiology and Physiology Research Group, Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway.
Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France.
BMC Vet Res. 2021 Jan 7;17(1):14. doi: 10.1186/s12917-020-02723-7.
Hibernation is a physiological and behavioural adaptation that permits survival during periods of reduced food availability and extreme environmental temperatures. This is achieved through cycles of metabolic depression and reduced body temperature (torpor) and rewarming (arousal). Rewarming from torpor is achieved through the activation of brown adipose tissue (BAT) associated with a rapid increase in ventilation frequency. Here, we studied the rate of rewarming in the European hamster (Cricetus cricetus) by measuring both BAT temperature, core body temperature and ventilation frequency.
Temperature was monitored in parallel in the BAT (IPTT tags) and peritoneal cavity (iButtons) during hibernation torpor-arousal cycling. We found that increases in brown fat temperature preceded core body temperature rises by approximately 48 min, with a maximum re-warming rate of 20.9℃*h. Re-warming was accompanied by a significant increase in ventilation frequency. The rate of rewarming was slowed by the presence of a spontaneous thoracic mass in one of our animals. Core body temperature re-warming was reduced by 6.2℃*h and BAT rewarming by 12℃*h. Ventilation frequency was increased by 77% during re-warming in the affected animal compared to a healthy animal. Inspection of the position and size of the mass indicated it was obstructing the lungs and heart.
We have used a minimally invasive method to monitor BAT temperature during arousal from hibernation illustrating BAT re-warming significantly precedes core body temperature re-warming, informing future study design on arousal from hibernation. We also showed compromised re-warming from hibernation in an animal with a mass obstructing the lungs and heart, likely leading to inefficient ventilation and circulation.
冬眠是一种生理和行为适应机制，能使动物在食物供应减少和环境温度极端的时期存活下来。这是通过代谢抑制和体温降低（蛰伏）以及复温（觉醒）的循环来实现的。从蛰伏状态复温是通过激活棕色脂肪组织（BAT）来实现的，这与通气频率的快速增加有关。在这里，我们通过测量BAT温度、核心体温和通气频率来研究欧洲仓鼠（Cricetus cricetus）的复温速率。
在冬眠蛰伏-觉醒循环期间，使用植入式体温记录器（IPTT标签）和纽扣式温度记录仪（iButtons）并行监测BAT和腹腔内的温度。我们发现棕色脂肪温度的升高比核心体温的升高提前约48分钟，最大复温速率为20.9℃/小时。复温过程中通气频率显著增加。我们的一只动物出现自发性胸腔肿物，导致复温速率减慢。核心体温复温速率降低了6.2℃/小时。与健康动物相比，患病动物在复温过程中通气频率增加了77%。对肿物位置和大小的检查表明它阻塞了肺部和心脏。
我们使用了一种微创方法来监测冬眠觉醒过程中的BAT温度，结果表明BAT复温明显先于核心体温复温，这为未来关于冬眠觉醒的研究设计提供了信息。我们还表明，一只肺部和心脏被肿物阻塞的动物冬眠复温能力受损，这可能导致通气和循环效率低下。
