Comet assay: an essential tool in toxicological research

Abstract

The comet assay is a versatile, reliable, cost-efficient, and fast technique for detecting DNA damage and repair in any tissue. It is useable in almost any cell type and applicable to both eukaryotic and prokaryotic organisms. Instead of highlighting one of the numerous specific aspects of the comet assay, the present review aims at giving an overview about the evolution of this widely applicable method from the first description by Ostling and Johanson to the OECD Guideline 489 for the in vivo mammalian comet assay. In addition, methodical aspects and the influence of critical steps of the assay as well as the evaluation of results and improvements of the method are reviewed. Methodical aspects regarding oxidative DNA damage and repair are also addressed. An overview about the most recent works and relevant cutting-edge reviews based on the comet assay with special regard to, e.g., clinical applications, nanoparticles or environmental risk assessment concludes this review. Taken together, the presented overview raises expectations to further decades of successful applications and enhancements of this excellent method.

The Ubiquitin E3/E4 Ligase UBE4A Adjusts Protein Ubiquitylation and Accumulation at Sites of DNA Damage, Facilitating Double-Strand Break Repair

“…Such sensitivity is suggestive of defective DSB repair. In order to directly examine the effect of UBE4A depletion on DSB sealing, we used the sensitive neutral comet assay (Glei et al, 2016) to measure the amount of DSBs remaining in genomic DNA after treatment with ionizing radiation (IR). Significant differences in comet tail moment (an actual measure of DSBs in the neutral comet assay) were observed between UBE4A-proficient and -depleted cells 24 hr after IR treatment (Figure 1C), indicating a marked, continuous retardation in DSB closure upon reduction of UBE4A level.…”

Genotoxic Assessment of the Dry Decoction of Myracrodruon urundeuva Allemão (Anacardiaceae) Leaves in Somatic Cells of Drosophila melanogaster by the Comet and SMART Assays

“…Under the experimental in vivo conditions in the study performed both assays indicate that M. urundeuva leaf dry decoction is genotoxic and mutagenic. According to Glei et al (), comparing comet assay results with data from other test systems to interpret the biological relevance is highly recommended (Olive and Banath ) and is an inherent part of genotoxicological test strategies (EFSA ). Also, in vivo genotoxicity tests, as we performed with D. melanogaster somatic cells are, in general, considered more specific than in vitro tests (Bolognesi et al ).…”

“…The Comet assay is useful to detect DNA single‐strand breaks that have not been repaired until the step of cell membrane lysis. Also, can be used for studies of DNA repair, providing important information on the kinetics and type of lesion repaired, although is unable to infer the reliability of the repair process (Glei et al ). In the other hand, SMART quantify both mutagenesis and recombination damages in the next cell generations.…”

The various aspects of genetic and epigenetic toxicology: testing methods and clinical applications

“…To date, the CA, as a soft and biological assay, has been used in many fields, such as: eco-genotoxicity [30], toxicology [31], pharmacology [32], and nutrigenomics [33]. Besides, the CA is also proposed to assess the levels of genetic damages in human diseases, like essential hypertension [34], chronic kidney disease (CKD) [35], type 2 diabetes [36], and even in cancer chemoprevention [37].…”