Allen D W, Cierzan J J
Department of Medicine, Veterans Administration Medical Center, Minneapolis, MN 55417.
J Lab Clin Med. 1988 Jul;112(1):87-91.
Factors relating the site and metabolic state of erythrocyte lipids to their susceptibility to oxidative stress are poorly understood. Therefore red cell lipids were labeled with serum albumin-bound (carbon 14 [ul]) fatty acids in timed experiments. Susceptibility of sequentially labeled lipids to peroxidation in intact cells was determined by the percent conversion of the [14C]lipid to [14C]malondialdehyde (MDA). Other effects of alteration of incubation times could be ruled out by the equality of the conversion of total cell lipid to MDA. Polyunsaturated fatty acids but not other fatty acids served as MDA precursors. In 12 normal subjects the percentage of [14C]arachidonate converted to MDA after 15 minutes of labeling (3.08% +/- 0.69%) exceeded the percentage after 3 hours of labeling (2.01% +/- 0.83%) (paired, two-sided t test, p less than 0.0001). This susceptibility was caused by presence of rapidly labeled polyunsaturated fatty acids not extractable with defatted albumin (F2). Depletion of erythrocyte adenosine triphosphate before incubation favored accumulation of F2 and increased percentage conversion to MDA. Peroxidative susceptibility is determined by the metabolic state of the cell and the site of the peroxidized lipid within the intracellular pools.
红细胞脂质的部位和代谢状态与其对氧化应激的易感性之间的关系目前还知之甚少。因此，在定时实验中，用与血清白蛋白结合的（碳14[微升]）脂肪酸标记红细胞脂质。通过[14C]脂质转化为[14C]丙二醛（MDA）的百分比来确定完整细胞中顺序标记脂质对过氧化的易感性。总细胞脂质向MDA转化的相等性可以排除孵育时间改变的其他影响。多不饱和脂肪酸而非其他脂肪酸是MDA的前体。在12名正常受试者中，标记15分钟后[14C]花生四烯酸转化为MDA的百分比（3.08%±0.69%）超过标记3小时后的百分比（2.01%±0.83%）（配对双侧t检验，p<0.0001）。这种易感性是由不能用脱脂白蛋白提取的快速标记的多不饱和脂肪酸（F2）的存在引起的。孵育前红细胞三磷酸腺苷的消耗有利于F2的积累，并增加向MDA的转化百分比。过氧化易感性由细胞的代谢状态和细胞内池内过氧化脂质的部位决定。
