Department of Lipid Science and Traditional Foods, Central Food Technological Research Institute, Council of Scientific and Industrial Research, Mysore-570 020, India.
J Nutr. 2011 Jan;141(1):24-30. doi: 10.3945/jn.110.127027. Epub 2010 Nov 24.
The concentration of LDL cholesterol in plasma is strongly influenced by the amount and type of lipid in the diet. Our studies have shown that positional changes in the fatty acids in blended oil introduced using lipase-catalyzed interesterification differentially modulate circulating LDL levels in rats compared with those observed in rats given a physical blend of oils. To investigate the molecular basis of these differences, transcriptional profiling of genes involved in cholesterol homeostasis was studied after feeding rats with a semipurified diet containing 10% fat from native oils; coconut oil (CNO), rice bran oil (RBO), or sesame oil (SESO); blended (B); CNO+RBO(B) or CNO+SESO(B) and interesterified oil (I); CNO+RBO(I) or CNO+SESO(I) for 60 d. Hepatic LDL receptor (LDL-R) expression significantly increased in rats fed interesterified oils by 100-200% compared with rats fed blended oils and by 400-500% compared with rats fed CNO. Positional alteration in fatty acids of oils used in the diet induced changes in LDL-R expression, which was accompanied by parallel changes in cholesterol-7α-hydroxylase (CYP7A1) and SREBP-2 genes. This suggested that not only the fatty acid type but also its position in the TG of dietary lipids play an important role in maintaining plasma cholesterol levels by suitably modulating gene expression for LDL-R in rat liver.
血浆中 LDL 胆固醇的浓度受饮食中脂质的数量和类型的强烈影响。我们的研究表明，使用脂肪酶催化的酯交换引入的混合油中的脂肪酸位置变化会使接受混合油的大鼠的循环 LDL 水平发生变化，与物理混合油的大鼠相比有所不同。为了研究这些差异的分子基础，在用含有天然油 10%脂肪的半纯化饮食喂养大鼠后，研究了参与胆固醇稳态的基因的转录谱；椰子油（CNO）、米糠油（RBO）或芝麻油（SESO）；混合（B）；CNO+RBO（B）或 CNO+SESO（B）和酯交换油（I）；CNO+RBO（I）或 CNO+SESO（I）60 d。与用混合油喂养的大鼠相比，用酯交换油喂养的大鼠的肝脏 LDL 受体（LDL-R）表达显著增加了 100-200%，与用 CNO 喂养的大鼠相比增加了 400-500%。饮食中使用的油脂的脂肪酸位置变化诱导 LDL-R 表达的变化，伴随着胆固醇-7α-羟化酶（CYP7A1）和 SREBP-2 基因的平行变化。这表明，不仅脂肪酸类型，而且其在膳食脂质 TG 中的位置，通过适当调节大鼠肝脏中 LDL-R 的基因表达，在维持血浆胆固醇水平方面也起着重要作用。
