The Effect of α-Tocopherol Supplementation on LDL Oxidation: A Dose-Response Study-猫眼课题宝

补充 α-生育酚对 LDL 氧化的影响：剂量反应研究

DOI：

发表时间：

1995

期刊：

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

I. Jialal;C. Fuller;B. Huet

摘要由于大量数据支持氧化修饰低密度脂蛋白 (Ox-LDL) 可以促进动脉粥样硬化形成的概念，因此抗氧化剂在减少低密度脂蛋白氧化方面的作用变得非常重要。人体补充高剂量 α-生育酚可降低 LDL 对氧化的敏感性。因此，本研究的目的是确定降低 LDL 对氧化敏感性的 α-生育酚的最小剂量。在一项为期 8 周的随机安慰剂对照研究中，测试了 60、200、400、800 和 1200 IU/天剂量的 α-生育酚对铜催化 LDL 氧化的影响。每组有八名受试者。通过硫代巴比妥酸反应物质 (TBARS) 测定在基线 8 小时的时间过程中和补充 8 周后测量共轭二烯和脂质过氧化物的形成来监测 LDL 的氧化。安慰剂和任何剂量的 α-生育酚均未产生任何副作用或对血浆脂蛋白谱产生不利影响。然而，随着α-生育酚补充剂剂量的增加，血浆和脂质标准化α-生育酚水平呈剂量依赖性增加。 LDL α-生育酚似乎也遵循类似的趋势。当检查 LDL 氧化的时程曲线和 LDL 氧化的动力学时，与基线相比，接受安慰剂或 α-生育酚 60 或 200 IU/d 的组在第 8 周时没有显着影响。然而，在接受至少 400 IU/天 α-生育酚的组中，LDL 对氧化的敏感性降低，如时程曲线的平均水平、滞后期延长和氧化速率降低所示。此外，血浆和 LDL α-生育酚与氧化滞后期显着相关，与氧化速率成反比。本研究结果表明，显着降低 LDL 对氧化的敏感性所需的 α-生育酚最小剂量为 400 IU/d。

Abstract Because much data have accrued to support the concept that oxidatively modified LDL (Ox-LDL) can promote atherogenesis, the role of antioxidants in decreasing LDL oxidation has assumed great importance. High-dose α-tocopherol supplementation in humans decreases the susceptibility of LDL to oxidation. Hence, the aim of the present study was to ascertain the minimum dose of α-tocopherol that would decrease the susceptibility of LDL to oxidation. The effect of α-tocopherol in doses of 60, 200, 400, 800, and 1200 IU/d on copper-catalyzed LDL oxidation was tested in a randomized placebo-controlled study over 8 weeks. There were eight subjects in each group. Oxidation of LDL was monitored by measuring the formation of conjugated dienes and lipid peroxides by the thiobarbituric acid–reacting substances (TBARS) assay over an 8-hour time course at baseline and after 8 weeks of supplementation. Neither placebo nor any of the doses of α-tocopherol resulted in any side effects or exerted an adverse effect on the plasma lipoprotein profile. However, there was a dose-dependent increase in plasma and lipid-standardized α-tocopherol levels with increasing doses of α-tocopherol supplementation. LDL α-tocopherol appeared to follow a similar trend. When the time-course curves of LDL oxidation and the kinetics of LDL oxidation were examined, there was no significant effect at 8 weeks compared with baseline in the groups that received placebo or α-tocopherol 60 or 200 IU/d. However, in the groups that received at least 400 IU/d α-tocopherol, there was a decreased susceptibility of LDL to oxidation, as shown by the mean levels in the time-course curves, prolongation in the lag phase, and a decrease in the oxidation rate. Furthermore, both plasma and LDL α-tocopherol correlated significantly with the lag phase of oxidation and inversely with the oxidation rate. The results of the present study show that the minimum dose of α-tocopherol needed to significantly decrease the susceptibility of LDL to oxidation is 400 IU/d.