Abstract
To assess the genotoxicity of nicotine, its DNA-damaging effect on Caenorhabditis elegans cells was tested with the alkaline single-cell microgel electrophoresis (comet) assay. The degree of DNA migration (a measure of possible DNA single-strand breaks, alkali-labile sites, and incomplete excision repair sites) was expressed as the head DNA%, tail length, and Olive tail moment. Large differences were found between experimental variants: 0, 1, 10, and 100 μM (-)-nicotine. At concentrations of 1 and 10 μM, no damages were detected by the comet assay, and the Olive tail moment and tail length were significantly lower than in the control (P < 0.001). The highest head DNA% and the lowest tail length and Olive tail moment were observed in the presence of 1 μM of nicotine. At 100 μM of nicotine, a significant increase (P < 0.001) was observed in Olive tail moment and tail length (up to 2.7- and 3-fold, respectively, compared to the control). The results are consistent with the lowest head DNA% among the three tested variants. This study demonstrated that nicotine treatment had dose-dependent effects on the level of DNA damage. Generally, a high dose of nicotine (100 μM) is genotoxic, while a reasonably low concentration has a protective effect. The possible participation of reactive oxygen species in the DNA-damaging potential of nicotine in C. elegans is discussed.
Acknowledgment
This study was supported by funds from the Department of Cell Biology, Faculty of Biology, Adam Mickiewicz University (Poznań, Poland).
Declaration of interest: The authors report no financial conflicts of interest. The authors alone are responsible for the content and writing of this paper.