INRA UMR 866, Dynamique Musculaire et Métabolisme, 34060 Montpellier, France.
Br J Nutr. 2013 Nov;110(10):1789-802. doi: 10.1017/S0007114513001311. Epub 2013 May 9.
The incidence of metabolic syndrome components including obesity, lipid deregulation, insulin resistance (IR) and non-alcoholic fatty liver disease is increasing rapidly in wealthy societies. The present study was designed to determine the effect of different nutritional lipid patterns (quantity and quality) on lipid utilisation and oxidative stress in the liver and muscle of rats in an integrated fashion. A total of forty-eight Wistar male rats were fed for 12 weeks with a mixed, lard or fish-oil diet, containing either 50 or 300 g lipid/kg. Rats developed liver steatosis associated with moderate liver injury when fed the 30% lipid diets, in spite of the absence of overt obesity or IR, except when fed the lard 30% lipid diet. The intake of the 30% lipid diets decreased hepatic lipogenesis and mitochondriogenesis and increased lipid peroxidation and protein oxidation. Surprisingly, muscle lipid content was not modified whatever the administered diet. The intake of the 30% lipid diets increased the muscle protein expression of fatty acid (FA) translocase/cluster of differentiation 36 (FAT/CD36), PPARg co-activator 1a (PGC-1a) and muscle carnitine palmitoyltransferase 1 (m-CPT1), reflecting increased FA transport in the muscle associated with increased oxidative metabolism. The lard 30% lipid diet led to IR without modifying the muscle lipid content. The fish-oil 30% lipid diet failed to prevent the development of hepatic steatosis and made the tissues more prone to oxidation. Overall, the present study suggests that the FA composition of muscle is more important than lipid accumulation itself in the modulation of insulin sensitivity, and indicates that precaution should be taken when advising an unphysiologically high (pharmacological) supplementation with long-chain n-3 PUFA.
在富裕社会中,包括肥胖、脂质失调、胰岛素抵抗(IR)和非酒精性脂肪肝在内的代谢综合征成分的发病率正在迅速上升。本研究旨在综合确定不同营养脂质模式(数量和质量)对大鼠肝脏和肌肉中脂质利用和氧化应激的影响。共有 48 只 Wistar 雄性大鼠分别用混合、猪油或鱼油饮食喂养 12 周,饮食中的脂质含量分别为 50 或 300g/kg。尽管没有明显的肥胖或 IR,但当用 30%脂质的猪油饮食喂养时,大鼠会发生肝脂肪变性,伴有中度肝损伤。当摄入 30%脂质饮食时,肝内脂生成和线粒体生成减少,脂质过氧化和蛋白质氧化增加。令人惊讶的是,无论给予何种饮食,肌肉脂质含量都没有改变。摄入 30%脂质饮食会增加肌肉脂肪酸(FA)转运蛋白/分化簇 36(FAT/CD36)、过氧化物酶体增殖物激活受体γ共激活因子 1a(PGC-1a)和肌肉肉毒碱棕榈酰转移酶 1(m-CPT1)的肌肉蛋白表达,这反映了与氧化代谢增加相关的肌肉中 FA 转运增加。猪油 30%脂质饮食会导致 IR,而不会改变肌肉脂质含量。鱼油 30%脂质饮食未能阻止肝脂肪变性的发生,使组织更容易氧化。总的来说,本研究表明,肌肉中 FA 的组成比脂质积累本身更能调节胰岛素敏感性,并表明在建议使用生理上过高(药理学)的长链 n-3PUFA 补充时应谨慎。