Rikke Brad A, Yerg John E, Battaglia Matthew E, Nagy Tim R, Allison David B, Johnson Thomas E
Institute for Behavioral Genetics, Campus Box 447, University of Colorado, Boulder 80309-0447, USA.
Mech Ageing Dev. 2003 May;124(5):663-78. doi: 10.1016/s0047-6374(03)00003-4.
Dietary restriction (DR, also referred to as calorie restriction, energy restriction, and food restriction) retards senescence and increases longevity in mammals. DR also lowers mean body temperature (T(b)), and thus mean T(b) might be useful as a covariate of DR-induced life extension. Indeed, lower T(b) could itself underlie some of the beneficial life-extension effects that occur during DR. To assess the relationship between lower T(b) during DR and life extension, we asked whether significant strain variation exists in the T(b) response of mice being fed 60% ad libitum (AL). Individually-housed, female mice from 28 strains, representing a genealogically diverse sample of the classical inbred strains, were directly compared. The mean T(b)s in response to DR exhibited highly significant strain variation, ranging from 1.5 degrees C below normal to a phenomenal 5 degrees C below normal. This variation was not explained by differences in loss of thermoregulation, AL adiposity, sensitivity to a nonadaptive hypothermia, motor activity, thermal arousal, absolute food intake, or efficacy of nutrient extraction. The variation in strain mean T(b) was also present in the absence of torpor. This strain variation could be used to critically test whether lower T(b) is a covariate of life extension during DR.
饮食限制（DR，也称为热量限制、能量限制和食物限制）可延缓哺乳动物衰老并延长寿命。DR还会降低平均体温（T(b)），因此平均T(b)可能作为DR诱导寿命延长的一个协变量。实际上，较低的T(b)本身可能是DR期间出现的一些有益寿命延长效应的基础。为了评估DR期间较低的T(b)与寿命延长之间的关系，我们询问了自由摄食（AL）量为60%的小鼠在T(b)反应方面是否存在显著的品系差异。对来自28个品系的单独饲养的雌性小鼠进行了直接比较，这些品系代表了经典近交系的一个谱系多样的样本。对DR的反应中，平均T(b)表现出高度显著的品系差异，范围从比正常体温低1.5摄氏度到惊人的比正常体温低5摄氏度。这种差异无法用体温调节丧失、AL肥胖、对非适应性低温的敏感性、运动活动、热唤醒、绝对食物摄入量或营养物质提取效率的差异来解释。品系平均T(b)的差异在无蛰伏状态下也存在。这种品系差异可用于严格检验较低的T(b)是否是DR期间寿命延长的一个协变量。
