2种共轭亚油酸异构体对小鼠肌内脂肪沉积和肌肉线粒体代谢的影响

Effects of Two Different Conjugated Linoleic Acid Isomers on Intramuscular Fat Deposition and Muscle Mitochondrial Metabolism in Mice

试验旨在研究不同共轭亚油酸异构体对小鼠肌内脂肪沉积和肌肉线粒体代谢的影响。将成长到5周龄的雄性小鼠按体重分成3组(每组8只),适应1周后分别饲喂不添加、添加2%的顺9反11共轭亚油酸(c9,t11-CLA)和添加2%的反10顺12共轭亚油酸(t10,c12-CLA)的日粮,正试期1个月,监测其体重和体组成的变化,饲养试验结束后采集血清检测甘油三酯和游离脂肪酸含量;采集肌肉检测甘油三酯含量,使用油红O染色直观检测肌内脂肪含量的变化;提取腓肠肌总RNA,通过使用荧光定量PCR方法检测腓肠肌部位与脂肪酸转运、线粒体合成和氧化代谢相关基因的变化。结果表明:日粮添加c9,t11-CLA和t10,c12-CLA异构体均可以降低小鼠体重和体增重、机体脂肪比例及血清甘油三酯含量(P<0.05),增加肌肉比例(P<0.05);与c9,t11-CLA异构体相比,日粮添加t10,c12-CLA异构体可以增加血清游离脂肪酸含量、小鼠肌肉甘油三酯和肌内脂肪含量(P<0.05),增加肌肉部位脂肪酸转运、线粒体生物合成和氧化代谢相关基因的表达(P<0.05)。由此可见,t10,c12-CLA在肌内脂肪沉积、肌肉部位线粒体生物合成和氧化代谢方面发挥着更显著作用。

This study was conducted to investigate the effects of different conjugated linoleic acid isomers(c9,t11-CLA,t10,c12-CLA)on intramuscular fat deposition and muscle mitochondrial metabolism in mice.Male mice at the age of 5 weeks were divided into 3 groups(8 mice per group)according to the body weight.After a week of adaptation,the control group was fed control diets while other two groups were fed diets supplemented with 2%c9,t11-CLA and 2%t10,c12-CLA respectively.The trial lasted for one month,and changes in body weight and body composition of mice were monitored.Serum samples were collected after slaughter to detect the contents of triglycerides and free fatty acids.Meanwhile,muscles were collected to detect the triglyceride content.Oil red O staining was used to directly detect the changes of intramuscular fat content.Total RNA was extracted from the gastrocnemius muscle,and changes of genes related to fatty acid transport,mitochondrial synthesis and oxidative metabolism were detected by fluorescence quantitative PCR.The results showed that dietary supplementation of c9,t11 and t10,c12 conjugated linoleic acid isomers significantly reduced body weight and body gain,decreased body fat proportion,increased muscle proportion,and decreased serum triglyceride content in mice.Compared with c9,t11 conjugated linoleic acid isomer,the supplementation of t10,c12 conjugated linoleic acid isomer significantly increased free fatty acid content in serum,triglyceride and intramuscular fat content in muscle,and increased the mRNA expression of fatty acid transporters,mitochondrial biosynthesis and oxidative metabolism genes in muscle.These results above indicated that t10,c12 conjugated linoleic acid plays a more significant role in intramuscular fat deposition,mitochondria biogenesis and oxidative metabolism in muscle.