McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, United States.
Department of Nutritional Sciences, University of Wisconsin-Madison, United States.
Biochimie. 2023 Jul;210:82-98. doi: 10.1016/j.biochi.2022.10.015. Epub 2022 Nov 11.
Thermoneutral housing has been shown to promote more accurate and robust development of several pathologies in mice. Raising animal housing temperatures a few degrees may create a relatively straightforward opportunity to improve translatability of mouse models. In this commentary, we discuss the changes of physiology induced in mice housed at thermoneutrality, and review techniques for measuring systemic thermogenesis, specifically those affecting storage and mobilization of lipids in adipose depots. Environmental cues are a component of the information integrated by the brain to calculate food consumption and calorie deposition. We show that relative humidity is one of those cues, inducing a rapid sensory response that is converted to a more chronic susceptibility to obesity. Given high inter-institutional variability in the regulation of relative humidity, study reproducibility may be improved by consideration of this factor. We evaluate a "humanized" environmental cycling protocol, where mice sleep in warm temperature housing, and are cool during the wake cycle. We show that this protocol suppresses adaptation to cool exposure, with consequence for adipose-associated lipid storage. To evaluate systemic cues in mice housed at thermoneutral temperatures, we characterized the circulating lipidome, and show that sera are highly depleted in some HDL-associated phospholipids, specifically phospholipids containing the essential fatty acid, 18:2 linoleic acid, and its derivative, arachidonic acid (20:4) and related ether-phospholipids. Given the role of these fatty acids in inflammatory responses, we propose they may underlie the differences in disease progression observed at thermoneutrality.
热中性饲养已被证明可促进小鼠多种病理学的更准确和稳健发展。将动物饲养温度升高几度可能会为提高小鼠模型的可转化性创造一个相对简单的机会。在这篇评论中,我们讨论了在热中性条件下饲养的小鼠所引起的生理学变化,并回顾了测量全身产热的技术,特别是那些影响脂肪组织中脂质储存和动员的技术。环境线索是大脑整合计算食物消耗和卡路里沉积的信息的组成部分。我们表明,相对湿度是这些线索之一,它会引起快速的感官反应,进而导致对肥胖的慢性易感性增加。鉴于相对湿度的调节在机构间存在高度变异性,因此考虑到这一因素可能会提高研究的可重复性。我们评估了一种“人性化”的环境循环方案,其中小鼠在温暖的温度下睡觉,而在清醒周期中保持凉爽。我们表明,该方案抑制了对凉爽暴露的适应,这对与脂肪相关的脂质储存产生了后果。为了评估在热中性温度下饲养的小鼠中的全身线索,我们对循环脂质组进行了表征,并表明血清中某些高密度脂蛋白相关磷脂高度耗竭,特别是含有必需脂肪酸 18:2 亚油酸及其衍生物花生四烯酸(20:4)和相关醚磷脂的磷脂。鉴于这些脂肪酸在炎症反应中的作用,我们提出它们可能是在热中性条件下观察到的疾病进展差异的基础。