Assessment of primary DNA damage in HepG2 cell line after acute exposure to alpha-cypermethrin and imidacloprid

Abstract

Question: Genotoxic effect of alpha cypermethrin (type II pyrethroid insecticide) and Imidacloprid (neonicotinoid insecticide) were evaluated on human hepatoma HepG2 cell line. Concentrations used corresponded to real-life exposures will be evaluated based on residential exposure levels (REL α cypermethrin= 0.003643 µg/mL ; REL Imidacloprid= 0.314 µg/mL), occupational exposure limits (OEL) for alpha cypermethrin 0.262 µg/mL, and AOEL (acceptable operator exposure level) for Imidacolprid, 0.13 µg/mL. Methods: Using the in vitro model of cell cultures, genotoxicity evaluation was made. In accordance with OECD guidelines, acute treatments (4h and 24h) was performed. Primary DNA damage was assessed by applying the alkaline comet assay. DNA damage was evaluated using two genotoxicity parameters: tail length and tail intensity, as well as LTN (long tail nuclei). Results: Concentration and time dependent genotoxic effects were observed in both compounds. The highest LTN frequencies observed after 24 h treatment with the α-cypermethrin was 35%. Frequencies of observed LTN reflected well actual concentration range, of both compounds tested (LTNREL Imidacloprid > LTNOEL α cypermethrin > LTNAOEL Imidacloprid > LTNREL α cypermethrin). Conclusions: Positive findings obtained by alkaline comet assay will serve to significantly extend the knowledge of both pollutants genotoxicity and might to contribute to the more relevant risk assessment. This work was financially supported by the Project No. 8366 Organic Pollutants in Environment - Markers and Biomarkers of Toxicity (OPENTOX), funded by the Croatian Science Foundation.