Abstract: Although, arsenic trioxide has been the subject of
toxicological research, in vitro cytotoxicity and genotoxicity studies
using relevant cell models and uniform methodology are not well
elucidated. Hence, the aim of the present study was to evaluate the
cytotoxicity and genotoxicity induced by arsenic trioxide in human
keratinocytes (HaCaT) using the MTT [3-(4, 5-dimethylthiazol-2-yl)-
2,5-diphenyltetrazolium bromide] and alkaline single cell gel
electrophoresis (Comet) assays, respectively. Human keratinocytes
were treated with different doses of arsenic trioxide for 4 h prior to
cytogenetic assessment. Data obtained from the MTT assay indicated
that arsenic trioxide significantly reduced the viability of HaCaT cells
in a dose-dependent manner, showing an IC50 value of 34.18 ± 0.6
μM. Data generated from the comet assay also indicated a significant
dose-dependent increase in DNA damage in HaCaT cells associated
with arsenic trioxide exposure. We observed a significant increase in
comet tail length and tail moment, showing an evidence of arsenic
trioxide -induced genotoxic damage in HaCaT cells. This study
confirms that the comet assay is a sensitive and effective method to
detect DNA damage caused by arsenic.