Pyrrole adducts in globin and plasma of workers exposed to hexane
Pyrrole adducts in globin and plasma of workers exposed to hexane
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DOI：
10.1007/s00420-019-01430-7
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发表时间：
2019-08-01
影响因子：
3
通讯作者：
Valentine, William M.
中科院分区：
文献类型：
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作者：
Ichihara, Gaku;Amarnath, Venkataraman;Valentine, William M.
目标 2,5-己二酮的尿液排泄量目前用于估计个体在前一个工作班次期间发生的己烷暴露水平。然而，由于己烷暴露和尿液 2,5-己二酮水平每天都有很大差异，并且需要亚慢性到慢性暴露于己烷才能产生神经病，因此该生物标志物可能无法准确反映个体患己烷神经病的风险。这项研究检查了球蛋白和血浆蛋白上产生的己烷衍生的吡咯加合物作为积分累积暴露标记物的潜力。由于吡咯标记物结合了己烷对 2,5-己二酮的生物活化以及己烷诱导的神经病变中涉及的蛋白质加合的初始步骤，因此它们可能可以通过反映神经系统内的致病事件作为效应生物标记物。此外，吡咯的形成是一种不可逆反应，表明己烷衍生的蛋白质吡咯可用于评估累积暴露，以更好地表征个体敏感性。方法为了检查所提出的标记物的实用性，从十一名使用己烷将浆料中的金属粉末造粒以生产金属加工模具工具的工人和四名未暴露的志愿者那里获得了血液样本。分离球蛋白和血浆，用胃蛋白酶消化蛋白质，与艾利希试剂反应，通过530nm处的吸光度测定吡咯加合物的水平。为了确定测定的剂量反应曲线和动态范围，将红细胞与一定浓度的 2,5-己二酮一起孵育，并测量分离的珠蛋白在 530 nm 处的净吸光度。结果在接触己烷的工人的珠蛋白和血浆样本中均检测到吡咯，并且大多数工人血浆中的吡咯水平与珠蛋白中的吡咯水平呈正相关。结论本研究表明：职业暴露于己烷后，外周蛋白上会产生可检测水平的己烷衍生蛋白质吡咯加合物，并支持测量吡咯以整合己烷累积暴露量的实用性。
ObjectivesUrinary excretion of 2,5-hexanedione is currently used to estimate the exposure levels of hexane occurring to an individual during the previous work shift. However, because hexane exposures and urinary 2,5-hexanedione levels can vary considerably from day to day, and subchronic to chronic exposures to hexane are required to produce neuropathy, this biomarker may not accurately reflect the risk of an individual for developing hexane neuropathy. This investigation examines the potential of hexane-derived pyrrole adducts produced on globin and plasma proteins as markers for integrating cumulative exposures. Because the pyrrole markers incorporate bioactivation of hexane to 2,5-hexandione and the initial step of protein adduction involved in hexane-induced neuropathy, they potentially can serve as biomarkers of effect through reflecting pathogenetic events within the nervous system. Additionally, pyrrole formation is an irreversible reaction suggesting that hexane-derived protein pyrroles can be used to assess cumulative exposures to provide a better characterization of individual susceptibilities.MethodsTo examine the utility of the proposed markers, blood samples were obtained from eleven workers who used hexane for granulating metal powders in a slurry to produce metal machining die tools and four non-exposed volunteers. Globin and plasma were isolated, and the proteins weredigested using pepsin, reacted with Ehrlich's reagent and the level of pyrrole adducts were determined by absorbance at 530nm. To determine the dose-response curve and dynamic range of the assay, erythrocytes were incubated with a range of 2,5-hexanedione concentrations and the net absorbance at 530nm of isolated globin was measured.ResultsPyrrole was detected in both the globin and plasma samples of the workers exposed to hexane and the levels of pyrroles in plasma were positively correlated with the levels of pyrroles in globin for most of the workers.ConclusionsThis investigation demonstrates that detectable levels of hexane-derived protein pyrrole adducts are produced on peripheral proteins following occupational exposures to hexane and supports the utility of measuring pyrroles for integrating cumulative exposures to hexane.