Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse 1, A-1160, Vienna, Austria.
Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Veterinärplatz 1, A-1210, Vienna, Austria.
Geroscience. 2020 Jun;42(3):897-907. doi: 10.1007/s11357-019-00148-1. Epub 2020 Feb 17.
Lipids, commonly split into saturated and mono- and polyunsaturated fatty acids, are key constituents of all biological membranes, and their exact proportions in different tissues were previously shown to be related to lifespan in mammals. As a mechanism, it was put forward that long-chain and highly unsaturated n-3 fatty acids may act as "pacemakers" in membranes while the n-6 fatty acid class may act as a counterbalance. Previously, long-lived Ames dwarf mice (Prop1 df/df) were found to have lower n-3 fatty acids and higher n-6 throughout their tissues. We exposed 32 adult (8 months old) Ames dwarf mice to three isocaloric diets differing in their fatty acid composition (saturated vs. rich in n-3 and n-6) for 2 months while measuring their body masses, subcutaneous body temperatures and finally membrane fatty acid profiles. Prominently, we found that individuals from all three groups quickly increased their body masses by ca. 20% and had 0.45 °C higher subcutaneous body temperatures than at baseline (F = 22.27; p < 0.001). Conceivably, experimental diets also largely reflected lipid composition found in the tissues with over 50% n-3 fatty acids in heart phospholipids from animals from the n-3-enriched feeding group. Our study indicates that fatty acid-enriched diets well affected body mass, subcutaneous body temperature and membrane fatty acid composition in Ames dwarf mice with no visible adverse effects on their health. Experimental feeding increased subcutaneous body fat and insulation, most likely explaining the higher subcutaneous temperatures.
脂质通常分为饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸，是所有生物膜的关键组成部分，其在不同组织中的精确比例先前被证明与哺乳动物的寿命有关。作为一种机制，有人提出长链和高度不饱和的 n-3 脂肪酸可能在膜中充当“起搏器”，而 n-6 脂肪酸类可能起平衡作用。先前发现，长寿的 Ames 矮小鼠（Prop1 df/df）的组织中 n-3 脂肪酸含量较低，n-6 脂肪酸含量较高。我们让 32 只成年（8 个月大）Ames 矮小鼠在三种等热量的饮食中暴露 2 个月，这三种饮食的脂肪酸组成不同（饱和与富含 n-3 和 n-6），同时测量它们的体重、皮下体温，最后测量它们的膜脂肪酸谱。突出的是，我们发现所有三组个体的体重都迅速增加了约 20%，并且皮下体温比基线高 0.45°C（F = 22.27；p < 0.001）。可以想象，实验饮食也在很大程度上反映了组织中的脂质组成，来自富含 n-3 饮食组的动物的心脏磷脂中的 n-3 脂肪酸超过 50%。我们的研究表明，富含脂肪酸的饮食对 Ames 矮小鼠的体重、皮下体温和膜脂肪酸组成有很好的影响，对其健康没有明显的不良影响。实验性喂养增加了皮下体脂和隔热层，这很可能解释了更高的皮下体温。
