Integration of in vitro neurotoxicity data with biokinetic modelling for the estimation of in vivo neurotoxicity
Integration of in vitro neurotoxicity data with biokinetic modelling for the estimation of in vivo neurotoxicity
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DOI：
10.1177/0960327106072994
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发表时间：
2007-04-01
影响因子：
2.8
通讯作者：
Blaauboer, Bas
中科院分区：
文献类型：
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作者：
Forsby, Anna;Blaauboer, Bas
神经毒性的风险评估主要基于体内暴露，其次是行为、生理和病理测试。在这项研究中，试图估计在单次或多次剂量暴露后观察到的最低神经毒性剂量。将分化的人神经母细胞瘤SH-SY5Y细胞暴露于丙烯酰胺、林丹、对硫磷、对氧磷、苯妥英、安定或咖啡因72小时。以生理终点为指标，研究其对蛋白质合成和细胞内游离钙离子浓度的影响。电压依赖性钙通道功能、乙酰胆碱受体功能和轴突退行性改变分别作为兴奋性、胆碱能信号转导和轴突病变的神经特异性终点。一般细胞毒性，即72小时暴露后的细胞总蛋白水平，用于与特定的终点进行比较，并用于估计急性致死率。每种化合物产生20%效应的最低浓度(EC20)被用作体内靶点最低神经毒性水平(LOEL)的替代物。在基于生理的生物动力学(PBBK)模型中，LOELs与化合物的吸附、分布、代谢和排泄数据相结合，并估计了受试化合物的最低观察有效剂量(LOEDs)。除安定外，所有受试化合物的估计LOEDs与文献中在老鼠身上发现的实验LOEDs之间有很好的相关性。然而，当使用文献中关于安定对γ-氨基丁酸(GABA)A受体功能的影响的体外数据来估计LOED时，估计的LOEDs与实验LOEDs之间的相关性从10000倍提高到10倍。我们的结果表明，在已知一些关于毒性机制的知识的情况下，通过将体外毒性数据作为最低观察到的靶组织水平的替代品与PBBK模型相结合来估计LOEDs是可能的。
Risk assessment of neurotoxicity is mainly based on in vivo exposure, followed by tests on behaviour, physiology and pathology. In this study, an attempt to estimate lowest observed neurotoxic doses after single or repeated dose exposure was performed. Differentiated human neuroblastoma SH-SY5Y cells were exposed to acrylamide, lindane, parathion, paraoxon, phenytoin, diazepam or caffeine for 72 hours. The effects on protein synthesis and intracellular free Ca2+ concentration were studied as physiological endpoints. Voltage operated Ca2+ channel function, acetylcholine receptor function and neurite degenerative effects were investigated as neurospecific endpoints for excitability, cholinergic signal transduction and axonopathy, respectively. The general cytotoxicity, determined as the total cellular protein levels after the 72 hours exposure period, was used for comparison to the specific endpoints and for estimation of acute lethality. The lowest concentration that induced 20% effect (EC20) obtained for each compound, was used as a surrogate for the lowest neurotoxic level (LOEL) at the target site in vivo. The LOELs were integrated with data on adsorption, distribution, metabolism and excretion of the compounds in physiologically-based biokinetic (PBBK) models of the rat and the lowest observed effective doses (LOEDs) were estimated for the test compounds. A good correlation was observed between the estimated LOEDs and experimental LOEDs found in literature for rat for all test compounds, except for diazepam. However, when using in vitro data from the literature on diazepam's effect on gamma-amino butyric acid (GABA)A receptor function for the estimation of LOED, the correlation between the estimated and experimental LOEDs was improved from a 10 000-fold to a 10-fold difference. Our results indicate that it is possible to estimate LOEDs by integrating in vitro toxicity data as surrogates for lowest observed target tissue levels with PBBK models, provided that some knowledge about toxic mechanisms is known.