Cordelli Eugenia, Bignami Margherita, Pacchierotti Francesca
Territorial and Production Systems Sustainability Department, Health Protection Technology Division, ENEA, CR Casaccia, Via Anguillarese 301, Rome 00123, Italy.
Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy.
Toxicol Res (Camb). 2021 Jan 5;10(1):68-78. doi: 10.1093/toxres/tfaa093. eCollection 2021 Jan.
The comet assay is a versatile method for measuring DNA strand breaks in individual cells. It can also be applied to cells isolated from treated animals. In this review, we highlight advantages and limitations of this comet assay in a regulatory context. Modified versions of the standard protocol detect oxidized DNA bases and may be used to reveal sites of DNA base loss, DNA interstrand crosslinks, and the extent of DNA damage induced indirectly by reactive oxygen species elicited by chemical-induced oxidative stress. The assay is, however, at best semi-quantitative, and we discuss possible approaches to improving DNA damage quantitation and highlight the necessity of optimizing protocol standardization to enhance the comparability of results between laboratories. As a genotoxicity test , the comet assay has the advantage over the better established micronucleus erythrocyte test that it can be applied to any organ, including those that are specific targets of chemical carcinogens or those that are the first sites of contact of ingested or inhaled mutagens. We illustrate this by examples of its use in risk assessment for the food contaminants ochratoxin and furan. We suggest that improved quantitation is required to reveal the full potential of the comet assay and enhance its role in the battery of approaches to characterize the mechanisms of toxicity and carcinogenicity of chemicals and to aid the determination of safe human exposure limits.
彗星试验是一种用于检测单个细胞中DNA链断裂的通用方法。它也可应用于从经处理动物中分离出的细胞。在本综述中，我们重点介绍了彗星试验在监管背景下的优点和局限性。标准方案的改良版本可检测氧化的DNA碱基，并可用于揭示DNA碱基丢失位点、DNA链间交联以及化学诱导的氧化应激引发的活性氧间接诱导的DNA损伤程度。然而，该试验充其量只是半定量的，我们讨论了改善DNA损伤定量的可能方法，并强调了优化方案标准化以提高实验室间结果可比性的必要性。作为一种遗传毒性试验，彗星试验相对于更为成熟的微核红细胞试验具有优势，即它可应用于任何器官，包括那些作为化学致癌物特定靶标的器官或那些作为摄入或吸入诱变剂首个接触位点的器官。我们通过其在食品污染物赭曲霉毒素和呋喃风险评估中的应用实例对此进行说明。我们认为，需要改进定量方法以充分发挥彗星试验的潜力，并增强其在一系列用于表征化学物质毒性和致癌机制以及辅助确定安全人体暴露限值的方法中的作用。
