DNA damage and DNA-protein cross-linking induced in rat intestine by the water disinfection by-product potassium bromate.

The genotoxic effects of potassium bromate (KBrO3), a food additive and water disinfection by-product, on the small intestine of rats are reported here. Adult male rats were given a single oral dose of KBrO3 (100 mg kg(-1) body weight) and sacrificed 12, 24, 48, 96 and 168 h after this treatment while control animals were not given KBrO3. Administration of KBrO3 caused a significant increase in DNA damage when analyzed by the comet assay which suggests the induction of DNA strand breaks. This was also shown by colorimetric assay of nucleotides formed upon DNA degradation. KBrO3 treatment also resulted in increased formation of DNA-protein cross-links in the intestine. The maximum changes in these parameters were 48 h after administration of KBrO3 after which recovery took place. Thus, a single oral dose of KBrO3 exerts genotoxic effects in the intestine of rats, possibly through the mechanism of oxidative DNA damage.