The comet assay in animal models: From bugs to whales – (Part 1 Invertebrates)

Abstract

The comet assay, also called single cell gel electrophoresis, is a sensitive, rapid and low-cost technique for quantifying and analysing DNA damage and repair at the level of individual cells. The assay itself can be applied on virtually any cell type derived from different organs and tissues of eukaryotic organisms. Although it is mainly used on human cells, the assay has applications also in the evaluation of DNA damage in yeast, plant and animal cells. Therefore, the purpose of this review is to give an extensive overview on the usage of the comet assay in animal models from invertebrates to vertebrates, covering both terrestrial and water biota. The comet assay is used in a variety of invertebrate species since they are regarded as interesting subjects in ecotoxicological research due to their significance in ecosystems. Hence, the first part of the review (Part 1) will discuss the application of the comet assay in invertebrates covering protozoans, platyhelminthes, planarians, cnidarians, molluscs, annelids, arthropods and echinoderms. Besides a large number of animal species, the assay is also performed on a variety of cells, which includes haemolymph, gills, digestive gland, sperm and embryo cells. The mentioned cells have been used for the evaluation of a broad spectrum of genotoxic agents both in vitro and in vivo. Moreover, the use of invertebrate models and their role from an ecotoxicological point of view will also be discussed as well as the comparison of the use of the comet assay in invertebrate and human models. Since the comet assay is still developing, its increasing potential in assessing DNA damage in animal models is crucial especially in the field of ecotoxicology and biomonitoring at the level of different species, not only humans.

Assessment of the Toxic Effects of Chitosan-Coated Magnetite Nanoparticles on Drosophila melanogaster

“…The Drosophila hemolymph includes three types of hemocytes: Plasmatocytes (95%) have the capacity to remove foreign material by phagocytosis; crystal cells (5%) are involved in melanin synthesis during pathogen encapsulation (Söderhäll and Cerenius, 1998); and lamellocytes, which are large, flattened cells whose differentiation is induced in response to patogens or the presence of foreign particles in the hemocoel (Carmona et al, 2015a;Cherry and Silverman, 2006;Irving et al, 2005;Lemaitre and Hoffmann, 2007). Also, the hemocytes are suitable cells to detect the DNA damage through the comet assay (Alaraby et al, 2015;Carmona et al, 2015b;Gajski et al, 2019). Lifespan of Drosophila could be critically influenced by the components of food, for example, the presence of iron in the diet produce accumulation of iron, shortening lifespan and senescence in the flies (Massie et al, 1985), while carotenoids, some amino acids and proteins prolong the lifespan due to their antioxidant action (Hoedjes et al, 2017;Zhang et al, 2014;Zhou et al, 2018).…”

The comet assay in animal models: From bugs to whales – (Part 2 Vertebrates)

“…Since the comet assay has been used for the evaluation of DNA damage in various animal models worldwide, the first part of the review paper Part I discussed invertebrate species from protozoans up to echinoderms [65], while Part II will give an extensive overview covering vertebrate species from chordates up to mammals (Table 1). As for invertebrates, the comet assay is also extensively used in a variety of vertebrate species.…”

Road related pollutants induced DNA damage in dragonfly nymphs (Odonata, Anisoptera) living in highway sedimentation ponds

“…Revealing genotoxicity by using the versatile and sensitive comet assay is a powerful and cost-efficient tool 36,37 and has been used in various environmental monitoring studies with various animals from both marine and fresh waters 37 . We have previously documented elevated DNA damage in the Eurasian minnow present in the Skullerud sedimentation pond 23 .…”