Assessment of DNA damage adopting comet assay. (A) DNA damage induced by CTN and OTA (individually and combined) after 24 h of treatment as revealed by comet assay. (B) DNA damage as defined according to the DNA in the tail. The multiple parts of each column (from the bottom to the top): intact (0–20%), slightly damaged (20–40%), damaged (40–60%), highly damaged (60–80%), and dead (80–100%). Data are expressed as mean ± SD of three independent experiments.