QUANTITATION OF BIOMARKERS OF OXIDATIVE STRESS BY NICI-MS

1996年，在NIEHS举办了关于测量人类氧化应激的讲习班。有一个普遍的共识是，开展一项研究，比较从同一样本测量的氧化应激的各种标记物，将是有价值的。其中一个这样的标记是F2a-异前列腺素，它通过NICI-MS进行定量。异前列腺素是一种类似前列腺素的化合物，它是由膜磷脂中花生四烯酸的化学氧化而不是酶催化氧化产生的。异前列腺素已被证明具有强大的生物活性，许多研究表明，它们是氧化应激动物模型中脂质过氧化的准确标记物。8-iso-F2a-isprostane是大多数研究中定量的特异性异构体。虽然最近有证据表明某些环氧合酶催化形成这种化合物，但酶途径的贡献似乎很小，主要是游离脂氧化的结果，而不是膜结合脂的结果。分析该化合物的标准方法是在负离子化学电离条件下，用五氟苯甲酯三甲基硅基衍生物的GC/MS进行分析。我们在这项研究中的作用是在内部建立生理样本中异前列腺素的测量方法，并与NIEHS/NIH的其他小组合作提供这一能力。还启动了一些其他研究，涉及将异前列烷作为氧化应激指标的测量：1)女性酒精研究P.Taylor(NCI)/D.Baer，J.Judd(USDA；2)OS.与突变的相关性(T.Deviaux，LMC)；在化学诱导的小鼠肝细胞腺瘤和癌中发现突变-假设突变是间接DNA损伤的结果，可能来自OS.；3)氧化应激、异前列腺素、NICI-MS在肺癌易感性中的作用(T·德弗劳克斯/A·帕特尔)--相关的异前列腺素/肿瘤产生(在小鼠中)

In 1996 a workshop on Measurement of Oxidative Stress in Humans was held at NIEHS. There was a general consensus that it would be valuable to mount a study comparing various markers of oxidative stress measured from the same sample. One such marker is F2a-isoprostane which is quantitated by NICI-MS. Isoprostanes are prostaglandin-like compounds that are produced as a result of the chemical rather than enzymatic oxidation of arachidonic acid in membrane phospholipids. The isoprostanes have been shown to possess potent biological activity, and a number of studies have shown them to be accurate markers of lipid peroxidation in animal models of oxidative stress. The 8-iso-F2a- isoprostane has been the specific isomer quantified in most studies. Although there is recent evidence for some cyclooxygenase catalyzed formation of this compound, the contribution of the enzymatic pathway has appeared to be minor and primarily the result of oxidation of free lipid rather than membrane-bound lipid. The standard method for analyzing this compound is by GC/MS of the pentafluorobenzyl ester trimethylsilyl derivative under negative ion chemical ionization conditions. Our role in this study has been to establish methodology in-house for the measurement of isoprostanes in physiological samples and to provide this capability in collaboration with other groups at NIEHS/NIH. A number of other studies involving measurement of isoprostanes as an indicator of oxidative stress have also been initiated: 1)Womens Alcohol Study P. Taylor (NCI)/D. Baer, J. Judd (USDA; 2) Correlation of O.S. with mutations (T. Devereaux, LMC); identified mutations in chemically induced mouse hepatocellular adenomas and carcinomas - hypothesize mutations are the result of indirect DNA damage, possibly from O.S.; 3)Role of O.S. in lung tumor susceptibility (T. Devereaux/A. Patel)- correlate isoprostane/tumor production (in mice) as a function of age - Oxidative stress, isoprostanes, NICI-MS