The in vivo comet assay is an established genotoxicity test, with an OECD test guideline, but in its standard form it measures only DNA strand breaks. Including in the assay an additional step, in which the DNA is incubated with a lesion-specific enzyme, can provide important information about the nature of the DNA damage. Formamidopyrimidine DNA glycosylase, 8-oxoguanine DNA glycosylase or endonuclease III are commonly used in the in vitro genotoxicity test and in human biomonitoring to detect oxidised bases, but in vivo applications are rarer. A systematic literature search has identified a total of 60 papers that report such in vivo experiments, testing a variety of agents. In many cases, strand breaks were not seen, but significant levels of enzyme-sensitive sites were induced - indicating a mechanism of action involving oxidative stress. Compounds such as methyl methanesulfonate (MMS) or ethyl methanesulfonate (EMS) could be used as positive controls in both the standard and the enzyme-modified in vivo comet assays.

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酶修饰彗星试验在体内研究中的作用

体内彗星试验是一种成熟的遗传毒性试验，符合 OECD 试验指南，但在其标准形式中，它仅测量 DNA 链断裂。在检测中包括一个额外的步骤，其中 DNA 与损伤特异性酶一起孵育，可以提供有关 DNA 损伤性质的重要信息。甲酰胺嘧啶 DNA 糖基化酶、8-氧鸟嘌呤 DNA 糖基化酶或核酸内切酶 III 常用于体外基因毒性试验和人体生物监测以检测氧化碱基，但在体内应用较少。系统的文献搜索已经确定了总共 60 篇报告此类体内实验的论文，测试了各种药剂。在许多情况下，没有看到链断裂，但诱导了显着水平的酶敏感位点 - 表明涉及氧化应激的作用机制。