In vitro biotransformation of surfactants in fish. Part II - Alcohol ethoxylate (C16EO8) and alcohol ethoxylate sulfate (C14EO2S) to estimate bioconcentration potential
In vitro biotransformation of surfactants in fish. Part II - Alcohol ethoxylate (C16EO8) and alcohol ethoxylate sulfate (C14EO2S) to estimate bioconcentration potential
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DOI：
10.1016/j.chemosphere.2009.04.011
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发表时间：
2009-08-01
期刊：
影响因子：
8.8
通讯作者：
Cravedi, Jean-Pierre
中科院分区：
文献类型：
--
作者：
Dyer, Scott D.;Bernhard, Mary Jo;Cravedi, Jean-Pierre
最近的监管压力(如REACH，CEPA)要求进行生物蓄积评估，以及减少动物使用的需要，增加了开发基于体外的方法来估计生物蓄积的必要性。我们的研究探索了利用亚细胞和细胞肝系统来确定两种表面活性剂的生物转化潜力：十八烷基乙二醇单十六烷基醚(C16EO8)和二甘醇单十四烷基醚硫酸盐(C14EO2S)。被测试的亚细胞系统是鲤鱼(Cyprinus Carpio)和虹鲑鱼(Oncorhynchus MykISS)的肝脏匀浆和微粒体。细胞系统由鲤鱼原代肝细胞、PLHC-1细胞、荒漠罗非鱼肝癌细胞系组成。每个体外系统暴露在放射性标记的测试化合物中，并使用液体闪烁和薄层层析方法检测生物转化。采用一级动力学方法估算生物转化速率。使用与通常用于预测鱼体内生物积累的质量平衡模型相关联的体外到体内代谢率外推模型来预测试验材料在鱼中的生物浓度。分别用微粒子、肝匀浆和肝细胞进行的亚细胞和细胞试验表明，亲本表面活性物质发生了生物转化。肝细胞的生物转化速度最快，其次是微粒体和匀浆。从匀浆试验到基于体内生物转化率的外推模型推算的转化率太低。鲑鱼微体代谢C16EO8的速度快于鲤鱼微体。然而，C14EO2S的费率大致相同。包含肝细胞体外生物转化率的预测值与体内测量或美国环保局的生物浓度模型(BCFWIN)预测值相似。根据鲑鱼和鲤鱼研究的微体比率预测的BCF值仅略低于默认的BCF值，后者假设BCF值与BCF值呈线性对数关系，没有生物转化。然而，基于肝细胞的结果显示，与默认的BCF值相比，BCFs显著降低。这些结果表明，基于体外代谢率的BCF值可以提供体内BCF值的合理估计，因此，支持在分级方法中使用体外方法来评估生物浓度。(C)2009爱思唯尔有限公司。保留所有权利。
Recent regulatory pressures (e.g., REACh, CEPA) requiring bioaccumulation assessments and the need for reduced animal use have increased the necessity for the development of in vitro-based methods to estimate bioaccumulation. Our study explored the potential use of subcellular and cellular hepatic systems to determine the biotransformation potential of two surfactants: octaethylene glycol monohexadecyl ether (C16EO8) and diethylene glycol monotetradecyl ether sulfate (C14EO2S). The subcellular systems tested were liver homogenates and microsomes from the common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss). Cellular systems consisted of primary hepatocytes from the common carp (C. carpio) and PLHC-1 cells, hepatocarcinoma cells from the desert topminnow, (Poeciliopsis lucida) cell line. Each in vitro system was exposed to radiolabeled test compounds and assayed for biotransformation using liquid scintillation and thin layer chromatographic methods. First-order kinetics were used to estimate rates of biotransformation. Bioconcentration of test materials in fish were predicted using an in vitro to in vivo metabolic rate extrapolation model linked to a mass-balance model commonly used to predict bioaccumulation in fish. Both subcellular and cellular tests using microsomes, liver homogenates and hepatocytes respectively showed biotransformation of the parent surfactants. Biotransformation rates were fastest for hepatocytes, followed by microsomes and homogenates. Rates were too low from homogenate tests to extrapolate to in vivo-based biotransformation rates using the extrapolation model. Trout microsomes metabolized C16EO8 faster than carp microsomes. yet rates were approximately the same for C14EO2S. Predicted BCF values incorporating in vitro biotransformation rates from hepatocytes were similar to measured in vivo or USEPA's bioconcentration model (BCFWIN) predicted values. Predicted BCF values using microsomal-based rates from trout and carp studies were only slightly less than default BCF values which assumes a linear log Kow to BCF relationship with no biotransformation. However, hepatocyte-based results showed substantially decreased BCFs compared to the default BCF values. These results indicate that BCF estimates based on in vitro metabolic rates can provide reasonable estimates of in vivo BCF values, therefore, supporting the use of in vitro approaches within a tiered approach to assess bioconcentration. (C) 2009 Elsevier Ltd. All rights reserved.