摘要
评估维生素E在体外的抗氧化、预防脂质过氧化的作用，比较各种不同类型脂肪乳剂对氧自由基产生及脂质过氧化的影响。取18例健康志愿者静脉血，采用Boyum法提取多核白细胞（PMN）并在体外培养PMN。实验分单纯PMN组，Intralipid组（100％LCT），Vasolipid组（50％LCT，50％MCT）Structolipid组（63％LCT，37％MCT）。各组均分为静止和刺激（用热灭活白色粘株菌刺激PMN）两种状态。采用NBT还原试验测定氧自由基产生量。根据以上分组在体外孵育PMN，并再分为添加Vit.E组和无Vit．E组。采用比色法─LPO-586测定脂质过氧化的终产物Malonaldehyde（MDA）和4-hydroxyalkenal来计算脂质过氧化程度。刺激组的氧自由基产生量明显高于静止组（0.795±0.180vs.0.405±0.090，P＜0.001）。脂肪乳剂可明显降低各组的NBT值，脂肪乳剂浓度与NBT值之间呈负线性相关（r＝-0.83，P＜0.001）。三组不同脂肪乳剂之间，其NBT值无统计学差异（P＞0．05）。刺激组的脂质过氧化产物明显高于静止组（3.15±1．12vs1.34±0.72，P＜0.001）。各脂肪乳剂组的脂质过氧化产物明显高于单纯PMN组，而Intralipid组脂质过氧化值高于Vasolipid组和Structolipid组，差异有显著性。随着PMN孵育时间的延长，各组的脂质过氧化值增加，6小时后接近?
Unsaturated fatty acids,a major component of fat emulsions used in parenteral nutrition,are prone to peroxidation that may be an important feature of oxygen-associated tissue damage. We used the nitroblue tetrazolium (NBT)reduction test to measure the production of superoxide radicals by stimulated polymorphonuclear neutrophils(PMN) in the presence of different fat emulsions: Intralipid (containing 100% long-chain triglycerides, LCT), Vasolipid (a physical mixture of 50% LCT and 50% medium-chain triglycerides, MCT), and Structolipid (structured triglycerides containing 63% LCT and 37% MCT). We measured the amount of malonaldehyde (MDA)and 4-hydroxyalkenal to determine the lipid peroxidation of the three fat emulsions in the presence of stimulated neutrophils. Further, we investigated the role of vitamin E(α-tocopherol)in preventing lipid peroxidation in vitro. The results showed that the values of NBT reduction of PMN was significantly decreased in each of the three fat emulsions and that increasing concentrations of fat emu1sions were associated with decreased values of NBT reductions, in a dose-dependent way(P < o. Ool ). There was, however, no statistically significant differences between the values of the three different types of fat emulsions(P >0. 05 ). lipid peroxidation increased significantly in the presence of all three types of fat emulsions, and was more pronounced for Intralipid than forVasolipid and Structolipid after 1 and 2 hours of incubation with resting as well as with stimulated phagocytes. The in creased lipid peroxidation of the fat emulsions was markedly reduced by vitamin E,and the inhibition was concentration dependent. In conclusion, lipid peroxidation in vitro is rnore pronounced when PMNs are incubated with fat emulsions. This increase in lipid peroxidation can be reduced by adding vitamin E to the fat emulsions.
出处
《中国临床营养杂志》
1999年第2期66-69,共4页
Chinese Journal of Clinical Nutrition
关键词
吞噬细胞
介导作用
脂肪乳剂
脂质过氧化
维生素E
抗氧化作用
氧化应激
Free radicals Nitroblue tetrazolium (NBT) test Lipid peroxidation Vitamin E(a-tocophero)Fat emulsion Neutrophil
