Standard and Fpg-modified comet assay in kidney cells of ochratoxin A- and fumonisin B 1-treated rats

Abstract

The effect of ochratoxin A (OTA), fumonisin B 1 (FB 1), and their combinations on DNA damage was studied using the standard alkaline comet assay and the Fpg-modified comet assay. Rats were orally receiving OTA (5 ng/kg b.w., 0.05 mg/kg b.w., and 0.5 mg/kg b.w., respectively) for 15 days, FB 1 (200 ng/kg b.w., 0.05 mg/kg b.w., and 0.5 mg/kg b.w., respectively) for 5 days, and the combinations of two lower OTA and FB 1 doses. The tail length, tail intensity, and Olive tail moment (OTM) obtained with the standard comet assay and Fpg-modified comet assay were significantly higher in treated animals than in controls, even at the lowest dose of OTA or FB 1 ( p < 0.01). The Fpg-modified comet assay showed significantly greater tail length, tail intensity, and OTM in all treated animal than did the standard comet assay ( p < 0.05), which suggests that oxidative stress is likely to be responsible for DNA damage. DNA damage detected by the standard comet assay at all OTA or FB 1 doses indicates that some other mechanism is also involved. Combined OTA + FB 1 treatment measured either by the standard comet or the Fpg-modified comet assay showed a synergistic increase in the tail intensity and OTM in kidney cells, even at doses that correspond to the daily human exposure in Europe.