固醇调节元件结合蛋白-1c基因54G/C多态性对高糖低脂膳食诱导的健康青年人血脂比值的影响

目的 探讨固醇调节元件结合蛋白-1c(sterol regulatory element-binding protein-1c,SREBP-1c)基因54G/C多态性对健康青年血脂比值的影响及在高糖低脂(high-carbohydrate/low-fat,HC/LF)膳食诱导的变化中的作用.方法 对56名健康志愿者,给予7 d平衡膳食和6 d HC/LF膳食,平衡膳食蛋白、脂肪、碳水化合物含量分别为15%,31%,54%,HC/LF膳食分别为15%,15%,70%.于第1 d,第8 d及第14 d抽取空腹12 h静脉血,测定血脂及血糖水平,计算血脂比值.分离血基因组DNA,聚合酶链反应-限制性酶切法分析SREBP-1c基因54G/C多态性.分析不同基因型间血脂比值及血糖的差异.结果 不同基因型受试者血脂比值及血糖基础值差异无统计学意义.平衡膳食后,无论是在受试人群整体还是将男女分组分析,不同基因型之间血脂比值及血糖均无统计学意义.HC/LF膳食后,女性C等位基因携带者低密度脂蛋白胆固醇/高密度脂蛋白胆固醇比值(loW density lipoprotein cholesterol/high density lipoprotein cholesterol,LDL-C/HDL-C)较GG纯合子显著升高(P＜0.05).与HC/LF膳食前相比,在受试人群整体,总胆固醇(total cholesterol,TC)/HDL-C比值和LDL-C/HDL-C在各基因型中均显著降低(P＜0.05).男女分组分析发现,HC/LF膳食后甘油三酯triglyceride(TG)/HDL-C比值和血浆致动脉硬化指数log(TG/HDL-C)在女性GG基因型受试者较膳食前显著升高(P＜0.05);而TC/HDL-C、LDL-C/HDL-C在HC/LF膳食后显著下降(P＜0.05),且不受性别和SREBP-1c基因54G/C位点多态性影响.结论 SREBP-1c基因54G/C多态性影响HC/LF膳食诱导的健康青年女性TG/HDL-C、log(TG/HDL-C)改变.C等位基因可能是一个对防止女性HC/LF膳食诱导的甘油三酯升高的保护性因素.

Effects of the 54G/C polymorphism of sterol regulatory element-binding protein-1c on changes of serum lipid ratios induced by high-carbohydrate/low-fat diet in healthy youth

Objective To investigate the effects of 54G/C polymorphism of sterol regulatory elementbinding protein-1c gene (SREBP-1c)on serum lipid ratios and their response to high-carbohydrate/low-fat(HC/LF) diet in healthy youth. Methods After a regular diet for 7 days of wash-out, 56 healthy youth (22.89±1.80 yrs) were given HC/LF diet for 6 days. The regular diet contained 54% carbohydrate, 15%protein, and 31% fat of the total energy. The HC/LF diet contained 70% carbohydrate, 15% protein, and 15% fat of the total energy. The serum lipids and glucose were measured on the 1st, 8th and 14th days.The ratios of TG/HDL-C, log (TG/HDL-C), TC/HDL-C, and LDL-C/HDL-C were calculated. The 54G/C polymorphism of SREBP-1c gene was analyzed by PCR-RFLP method. Results No significant difference was found in lipid ratios and glucose at baseline and after regular diet in subjects with different genotypes in either the whole studied population or in males or females only. However, after HC/LF diet, LDL-C/HDL-C was significantly lower in females carrying the C allele than those of GG homozygotes (P＜ 0.05).Compared with those before HC/LF diet, TC/HDL-C and LDL-C/HDL-C were significantly decreased in all the subjects (P＜0.05). When gender was taken into account, significant increase of TG/HDL-C and log(TG/HDL-C) was found only in females with GG genotype (P＜0.05). All the subjects experienced significant decrease of TC/HDL-C and LDL-C/HDL-C regardless of their genders and genotypes (P＜0.05). Conclusion The 54G/C polymorphism of SREBP-1c gene can influence the response of TG/HDL-C and log(TG/HDL-C) to HC/LF diet in females. The C allele may be a protective factor to prevent the increase of TG induced by HC/LF diet in females.