Evelo C T, Spooren A A, Bisschops R A, Baars L G, Neis J M
Department of Pharmacology, Universiteit Maastricht, The Netherlands.
Blood Cells Mol Dis. 1998 Sep;24(3):280-95. doi: 10.1006/bcmd.1998.0194.
The toxic potency of three industrially used hydroxylamines was studied in human blood cells in vitro. The parent compound hydroxylamine and the O-ethyl derivative gave very similar results. Both compounds induced a high degree of methemoglobin formation and glutathione depletion. Cytotoxicity was visible as Heinz body formation and hemolysis. High levels of lipid peroxidation occurred, in this respect O-ethyl hydroxylamine was more active than hydroxylamine. In contrast H2O2 induced lipid peroxidation was lowered after O-ethyl hydroxylamine or hydroxylamine treatment, this is explained by the ferrohemoglobin dependence of H2O2 induced radical species formation. Glutathione S-transferase (GST) and NADPH methemoglobin reductase (NADPH-HbR) activities were also impaired, probably as a result of the radical stress occurring. The riboflavin availability was decreased. Other enzyme activities glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH), glucose phosphate isomerase and NADH methemoglobin reductase, were not or only slightly impaired by hydroxylamine or O-ethyl hydroxylamine treatment. A different scheme of reactivity was found for N,O-dimethyl hydroxylamine. This compound gave much less methemoglobin formation and no hemolysis or Heinz body formation at concentrations up to and including 7 mM. Lipid peroxidase induction was not detectable, but could be induced by subsequent H2O2 treatment. GST and NADPH-HbR activities and riboflavin availability were not decreased. On the other hand GR and G6PDH activities were inhibited. These results combined with literature data indicate the existence of two different routes of hematotoxicity induced by hydroxylamines. Hydroxylamine as well as O-alkylated derivatives primarily induce methemoglobin, a process involving radical formation. The radical stress occurring is probably responsible for most other effects. N-alkylated species like N,O-dimethyl hydroxylamine primarily lead to inhibition of the protective enzymes G6PDH and GR. Since these enzymes play a key role in the protection of erythrocytes against oxidative stress a risk of potentiation during mixed exposure does exist.
在体外人体血细胞中研究了三种工业用羟胺的毒性强度。母体化合物羟胺和O - 乙基衍生物给出了非常相似的结果。两种化合物都诱导了高度的高铁血红蛋白形成和谷胱甘肽耗竭。细胞毒性表现为海因茨小体形成和溶血。发生了高水平的脂质过氧化，在这方面O - 乙基羟胺比羟胺更具活性。相比之下，在O - 乙基羟胺或羟胺处理后，H2O2诱导的脂质过氧化降低了，这可以通过H2O2诱导的自由基形成对高铁血红蛋白的依赖性来解释。谷胱甘肽S - 转移酶（GST）和NADPH高铁血红蛋白还原酶（NADPH - HbR）活性也受到损害，这可能是自由基应激发生的结果。核黄素的可用性降低。其他酶活性，如谷胱甘肽还原酶（GR）、葡萄糖6 - 磷酸脱氢酶（G6PDH）、葡萄糖磷酸异构酶和NADH高铁血红蛋白还原酶，在羟胺或O - 乙基羟胺处理后未受影响或仅略有损害。对于N，O - 二甲基羟胺发现了不同的反应模式。该化合物在浓度高达并包括7 mM时产生的高铁血红蛋白形成要少得多，并且没有溶血或海因茨小体形成。脂质过氧化物酶诱导未检测到，但随后的H2O2处理可诱导。GST和NADPH - HbR活性以及核黄素可用性未降低。另一方面，GR和G6PDH活性受到抑制。这些结果与文献数据相结合表明存在两种由羟胺诱导的血液毒性不同途径。羟胺以及O - 烷基化衍生物主要诱导高铁血红蛋白，这一过程涉及自由基形成。发生的自由基应激可能是大多数其他效应的原因。N - 烷基化物质如N，O - 二甲基羟胺主要导致保护性酶G6PDH和GR的抑制。由于这些酶在保护红细胞免受氧化应激方面起关键作用，在混合暴露期间确实存在增强的风险。
