In vitro genotoxicity of fipronil sister chromatid exchange, cytokinesis block micronucleus test, and comet assay.

Fipronil (FP) is a phenylpyrazole pesticide developed by the transnational company Rhône-Poulenc Agro in 1987. Data on the genotoxicity and toxicity of FP are rather inadequate. In this study, we aimed to evaluate the potential genotoxic activity of FP using the single-cell microgel electrophoresis or comet assay, sister chromatid exchanges (SCEs), and micronuclei (MN) in human peripheral blood lymphocytes. In addition, the cytokinesis block proliferation index (CBPI) and proliferation index (PRI) were measured for cytotoxicity. In this study, three different doses of FP were used (0.7, 0.3, 0.1 μg/mL). Mitomycin C (2 μg/mL) and hydrogen peroxide were used as positive controls for SCE MN test systems, and comet assay, respectively. FP induced a statistically significant increase in the MN and SCE frequency and DNA damage in a dose-dependent manner in human peripheral blood lymphocytes (p<0.01, p<0.05, for 0.7 and 0.3 μg/mL, respectively) compared with a negative control. There is no significant difference between 0.1 μg/mL and the negative control for MN frequency, but there is significant difference between all the doses of FP and negative control for SCE frequency, mitotic index, CBPI, and PRI values (p<0.01). Using the alkaline comet assay, we showed that all the doses of the FP induced DNA damage in human peripheral blood lymphocytes in vitro (p<0.05).