Use of the alkaline in vivo Comet assay for mechanistic genotoxicity investigations

Abstract

The alkaline Comet assay was used to investigate the in vivo genotoxicity of 17 compounds. Altogether 21 studies were conducted with these compounds. The investigations were triggered for various reasons. The main reason for performing the studies was to evaluate the in vivo relevance of in vitro genotoxicity findings with 10 compounds. Eight of these compounds showed no effects in the in vivo Comet assay while two compounds induced altered DNA migration patterns in specific organs. The remaining seven compounds were tested to follow up on neoplastic/preneoplastic or chronic toxicity changes as detected in specific target organs identified in rodent studies, to investigate the possibility of site-of-contact genotoxicity and to test the liver as a target organ for a suspected reactive metabolite. For the studies, various organs of rodents were analyzed, depending on the suspected properties of the compounds, including liver, jejunum, leukocytes, stomach mucosa, duodenum, lung and kidney. All tissues were amenable to investigation by gel electrophoresis after simple disaggregation of organs by means of mincing or, in the case of epithelial cells from the gastrointestinal tract, scraping off cells from the epithelium. In conclusion, the Comet assay was found to be a reliable and robust test to investigate in vivo genotoxicity in a variety of rodent organs. Therefore, it is concluded that in vivo Comet assay data are useful for elucidating positive in vitro genotoxicity findings and to evaluate genotoxicity in target organs of toxicity.

Evaluation of genotoxicity by comet assay (single-cell gel electrophoresis) in tissues of the fish Cyprinus carpio during sub-lethal exposure to Karanjin

“…The alkaline comet assay was performed according to Tice et al (2000), as modified by Hartman et al (2004) and Lemos, Dias, Silva-Souza, & Mantovani (2005). Cells are combined at 1 × 10 5 /ml with molten low-melting agarose (LM Agarose) (at 37°C) at a ratio of 1:10 (v/v), and immediately, 50 μl of it is pipetted out onto a comet slide which was placed on a flat surface at 4°C in the dark for 10 min.…”

Implications arising from the use of Cymbopogen proximus ; proximal on placenta of pregnant Albino rats

“…Terpenes, tannins, flavonoids, saponins, alkaloids, carbohydrate or glycosides, and phenolic glycosides are the phytochemical compositions which are found in the aqueous extract of C. proximus [2], [3]. Even for efficient and documented herbal medicinal products, the toxicity can be relatively undetected; unlike, the conventional drugs research and development, the toxicity of usual herbal medicines is not often estimated [4], [5], [6]. The majority of the population however does not give awareness, believing that, if these products have been used yet, they should be free from toxicity [7], [8a, b], [9], [10], [11].…”

Angiotensin II Induces DNA Damage in the Kidney

“…The comet assay is a rapid and quantitative method to measure DNA damage in any tissue, provided that a single-cell suspension can be obtained (21,22). Its greatest advantage is its applicability to terminally differentiated nondividing cells, such as cells out of the isolated perfused kidney.…”