Ferguson Melissa, Sohal Barbara H, Forster Michael J, Sohal Rajindar S
Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, United States.
Mech Ageing Dev. 2007 Oct;128(10):539-45. doi: 10.1016/j.mad.2007.07.005. Epub 2007 Aug 2.
The hypothesis, that a decrease in metabolic rate mediates the life span prolonging effect of caloric restriction (CR), was tested using two strains of mice, one of which, C57BL/6, exhibits life span extension as a result of CR, while the other, DBA/2, shows little or no effect. Comparisons of the rate of resting oxygen consumption and body temperature were made between the strains after they were fed ad libitum (AL) or maintained under 40% CR, from 4 to 16 months of age. Ad libitum-fed mice of the two strains weighed the same when young and consumed similar amounts of food throughout the experiment; however, the C57BL/6 mice weighed 25% more than DBA/2 mice at 15 months of age. The rate of oxygen consumption was normalized as per gram body weight, lean body mass or organ weight as well as per animal. The body temperature and the rate of oxygen consumption, expressed according to all of the four criteria, were decreased in the DBA/2 mice following CR. The C57BL/6 mice also showed a CR-related decrease in body temperature and in the rate of oxygen consumption per animal and when normalized according to lean body mass or organ weight. The results of this study indicate that CR indeed lowers the rate of metabolism; however, this effect by CR does not necessarily entail the prolongation of the life span of mice.
使用两种品系的小鼠对代谢率降低介导热量限制（CR）延长寿命效应这一假说进行了测试。其中一种品系C57BL/6，热量限制使其寿命延长；而另一种品系DBA/2，热量限制对其寿命几乎没有影响。在4至16月龄期间，对随意进食（AL）或维持40%热量限制的品系小鼠的静息耗氧率和体温进行了比较。两种品系随意进食的小鼠在年轻时体重相同，且在整个实验过程中消耗的食物量相似；然而，15月龄时C57BL/6小鼠的体重比DBA/2小鼠重25%。耗氧率按每克体重、瘦体重或器官重量以及每只动物进行了标准化。按照所有这四个标准表示，热量限制后DBA/2小鼠的体温和耗氧率均降低。C57BL/6小鼠在体温以及每只动物的耗氧率方面，以及按瘦体重或器官重量标准化时，也显示出与热量限制相关的降低。本研究结果表明，热量限制确实会降低代谢率；然而，热量限制的这种效应并不一定会延长小鼠的寿命。
