高脂与高果糖喂养大鼠对骨骼肌脂代谢相关蛋白基因表达的影响

Influence of High-Fat Feeding and High-Fructose Feeding on the Gene Expressions of Lipid-Metabolism-Related Enzymes in Skeletal Muscles of Rats

目的观察高脂、高果糖饮食喂养大鼠骨骼肌细胞内脂代谢相关蛋白基因表达的变化,比较两种不同饮食因子对大鼠肌肉脂代谢的影响。方法 Wistar雄性大鼠随机分为对照组、高脂组及高果糖组,分别喂养8周,测定3组大鼠空腹血糖(FBG)、空腹胰岛素(FINS)、骨骼肌三酰甘油(TG),正常葡萄糖高胰岛素钳夹技术测定葡萄糖输注率(GIR),并测定骨骼肌脂质转运相关蛋白:脂蛋白酯酶(LPL)和脂肪酸转位酶(FAT/CD36);脂质合成相关蛋白:肌肉固醇调节元件结合蛋白-1c(SREBP-1c)、脂肪酸合成酶(FAS)、乙酰辅酶A羧化酶(ACC)、硬脂酰CoA去饱和酶(SCD-1)和脂质氧化相关蛋白:肉毒碱棕榈酰基转移酶1β(CPTⅠβ)、解偶联蛋白3(UCP3)的基因表达。结果与对照组相比,高脂组及高果糖组FBG、FINS、骨骼肌TG均增高,差异有统计学意义(P<0.05);而GIR则显著下降,差异有统计学意义(P<0.05);与对照组相比,高脂组及高果糖组中LPL、FAT/CD36和SREBP-1c、FAS、ACC、SCD-1的基因表达增加,差异均有统计学意义(P<0.05);同时,CPTⅠβ和UCP3的基因表达亦增加,差异均有统计学意义(P<0.05)。结论高脂饮食和高果糖饮食均可引起机体的胰岛素抵抗及骨骼肌脂质堆积,肌肉内脂肪堆积与脂质转运增强、脂质合成增加有关,同时肌肉内脂质氧化相关酶类基因表达亦适应性增加。

Objective To investigate the effects of two different dietary factors on muscle lipid metabolism by observing the changes in gene expressions of lipid-metabolism-related enzymes in muscle tissue in both high-fat fed mice and high-fructose fed mice.Methods Male Wistar rats were randomly divided into control group,high-fat group and high-fructose group,with each group being fed for 8 weeks.Fasting blood glucose,plasma insulin,triglyceride（TG） in muscle tissues were measured in 3 groups.Glucose input rate（GIR） was evaluated by hyperinsulinemic euglycemic clamp study.The gene expressions of lipid-transportation-related enzymes：lipoprotein lipase（LPL）,fatty acid translocase CD36（FAT/ CD36）;lipid-synthesis-related proteins：sterol regulatory element binding protein-1c（SREBP-1c）,fatty acid synthase（FAS）,acytel CoA carboxylase（ACC）,stearoyl-CoA desaturase 1（SCD-1） and lipid-oxidation-related proteins：carnitine palmitoyltransferase-1β（CPTⅠβ）,uncoupling protein 3（UCP3） in muscle tissues were also detected.Results Compared with control group,blood glucose,plasma insulin,and TG content in muscle tissues were significantly increased while GIR was significantly decreased in both high-fat group and high-fructose group（P0.05）.Compared with control group,the gene expressions of LPL,FAT/ CD36,SREBP-1c,FAS,ACC and SCD-1 in muscle were significantly increased in high-fat group and high-fructose group（P0.05）.Meanwhile,the gene expressions of CPTⅠβ and UCP3 were significantly increased（P0.05）.Conclusion Whole-body insulin resistance,muscle triglyceride accumulation can be induced by both high-fat feeding and high-fructose feeding.Lipid accumulation in muscle is associated with the increased gene expressions of lipid-transportation-related and lipid-synthesis-related proteins.The gene expressions of lipid-oxidation-related proteins were also increased accordingly.