不同脂肪酸构成对大鼠肝脏HMG-CoAR、SREBP-1c表达的影响

目的探讨不同膳食脂肪酸构成比对大鼠脂质代谢相关基因HMG-CoAR、SREBP-1c的mRNA表达的影响。方法雌性SD大鼠随机分成6组,喂养6种不同膳食脂肪酸组成的饲料,即饱和脂肪酸组（SFA）、单不饱和脂肪酸组（MUFA）、n-6多不饱和脂肪酸组（n-6 PUFA）、n-3多不饱和脂肪酸组（n-3 PUFA）、1：1 n-6/n-3组及普通饲料喂养组,持续喂养18 w。并在实验第8 w和18 w时,提取大鼠肝脏组织,利用RT-PCR技术检测大鼠肝脏组织中HMG-CoAR、SREBP-1c mRNA表达状况。结果与对照组相比较,SFA能非常显著地升高HMG-CoAR mRNA的表达（P〈0.01）,MUFA能显著降低HMG-CoAR的基因表达（P〈0.05）,而PUFA则能够显著降低HMG-CoAR和SREBP-1c的基因表达（P〈0.05）。且在相同的总脂肪含量下,n-3 PUFA和n-6/n-3配比的膳食干预效果优于n-6 PUFA。结论 SFA、MUFA主要是通过HMG-CoAR途径来调控机体的脂质代谢,它们对SREBP-1c的表达无明显影响。PUFA调节血脂的作用机制可能与脂代谢基因HMG-CoAR和SREBP-1c有关。

Effects of different dietary fatty acid composition on HMG-CoAR and SREBP-1c expression in rat liver

Objective To study the effects of different dietary fatty acid composition on the mRNA expression of two rat lipid metabolism-related genes-HMG-CoAR and SREBP-1c.Methods 48 female rats were randomly divided into six groups and respectively fed with six diets containing different fatty acid for 18 w as follow： saturated fatty acid（SFA）,monounsaturated fatty acid（MUFA）,n-6 polyunsaturated fatty acid（n-6 PUFA）,n-3 PUFA,1∶ 1 n-6/n-3 PUFA and general diet（control group）.After feeding for 8 and 18 w,liver tissues of animals were obtained to detect the mRNA expression of HMG-CoAR and SREBP-1c using RT-PCR.Results Compared with general diet,SFA could increase the mRNA expression of HMG-CoAR very significantly（P0.01）,while MUFA could decrease it significantly（P0.05）.Both mRNA expression of HMG-CoAR and SREBP-1c deceased significantly in the three PUFA groups compared with control group（P0.05 or P0.01）.SREBP-1c expression dropped more obviously in n-3 PUFA and n-6/n-3 PUFA groups than that in n-6 PUFA group（P0.01）.Moreover,n-3 PUFA or n-6/n-3 PUFA had better lipid-lowering effect than n-6 PUFA when the total amount of lipid was similar.Conclusion SFA and MUFA appear to regulate body lipid metabolism mainly through HMG-CoAR path.They have little impact on SREBP-1c expression.However,PUFA may regulate body lipid metabolism through both HMG-CoAR path and SREBP-1c path.