Pamplona R, Portero-Otín M, Riba D, Ruiz C, Prat J, Bellmunt M J, Barja G
Department of Basic Medical Sciences, Faculty of Medicine, University of Lleida, Spain.
J Lipid Res. 1998 Oct;39(10):1989-94.
The oxidative stress theory of aging predicts a low degree of fatty acid unsaturation in tissues of longevous animals, because membrane lipids increase their sensitivity to oxidative damage as a function of their unsaturation. Accordingly, the fatty acids analyses of liver mitochondria from eight mammals, ranging in maximum life span from 3.5 to 46 years, show that the total number of double bonds and the peroxidizability index are negatively correlated with maximum life span (r = -0. 88, P < 0.003; r = -0.87, P < 0.004, respectively). This is not due to a low content of unsaturated fatty acids in longevous animals, but mainly to a redistribution between kinds of the polyunsaturated n-3 fatty acids series, shifting from the highly unsaturated docosahexaenoic acid (r = -0.89, P < 0.003) to the less unsaturated linolenic acid (r = 0.97, P < 0.0001). This redistribution pattern strongly suggests the presence of a constitutively low delta6-desaturase activity in longevous animals (r = -0.96, P < 0.0001). Thus, it may be proposed that, during evolution, a low degree of fatty acid unsaturation in liver mitochondria may have been selected in longevous mammals in order to protect the tissues against oxidative damage, while maintaining an appropriate environment for membrane function.
衰老的氧化应激理论预测，长寿动物组织中的脂肪酸不饱和度较低，因为膜脂对氧化损伤的敏感性会随着其不饱和度的增加而提高。相应地，对8种哺乳动物肝脏线粒体的脂肪酸分析表明，双键总数和过氧化指数与最大寿命呈负相关（相关系数分别为r = -0.88，P < 0.003；r = -0.87，P < 0.004）。这并非是因为长寿动物体内不饱和脂肪酸含量低，而是主要由于多不饱和n-3脂肪酸系列中不同种类之间的重新分布，从高度不饱和的二十二碳六烯酸（r = -0.89，P < 0.003）转向不饱和程度较低的亚麻酸（r = 0.97，P < 0.0001）。这种重新分布模式强烈表明长寿动物体内存在组成性低水平的δ6-去饱和酶活性（r = -0.96，P < 0.0001）。因此，可以提出，在进化过程中，长寿哺乳动物肝脏线粒体中较低程度的脂肪酸不饱和度可能是为了保护组织免受氧化损伤，同时维持适合膜功能的环境而被选择出来的。
