Thiacloprid (TH), one of the most widely used pesticides in the world, might cause toxic effects like DNA damage in humans and animals due to their frequent use. Accordingly, this study investigated TH's potential DNA-damaging effects on zebrafish liver via alkaline comet assay. Two treatment groups of ten zebrafish each were exposed to TH at two different concentrations, 1.64 and 0.82 mg/L, for 21 days and compared with an untreated control group. After exposure, the fishes' liver tissues were excised, and an alkaline comet assay was performed. Two slides per sample and 50 cells per slide were assessed with a visual evaluation program. The average DNA Damage values of the control, 0.82 mg/L TH, and 1.64 mg/L TH groups were 4.37 ± 5.12, 8.51 ± 8.54, and 9.30 ± 9.99, respectively. Both TH treatment groups had statistically significantly more DNA damage than the control group (p < 0.001). When comparing the TH treatment groups alone, the 1.64 mg/L dose group featured greater damage than the 0.82 mg/L dose group (p < 0.05). TH therefore causes significant DNA damage to the liver in a dose-dependent manner, revealing it to be a genotoxic agent that should be further investigated.
Keywords: Comet assay; insecticide; neonicotinoid; pesticide; risk assessment.