GENOTOXICITY OF ETHIDIUM BROMIDE IN ALBINO MICE TREATED WITH BACTERIAL PROBIOTIC

Ethidium bromide (EtBr) is a nucleic acid intercalating agent used extensively as a fluorescent dye in molecular genetics laboratories. The current study aimed to determine the potential  histo- and genotoxicity of EtBr and investigate the antigenotoxic effect of probiotic bacteria (Lactic Acid bacteria; LAB) on mammalian tissue (albino mice). Mice were randomly divided into seven groups, with seven different treatments. Different EtBr doses were used individually as drinking solutions with and without probiotic bacteria, which was introduced as a single dose as a food additive. After one month of the treatments, the liver was tested using histological assay, DNA fragmentation analysis, and quantitative RT-PCR technique. No significant genotoxic effect for EtBr on the liver was observed on histo- logical examination and DNA fragmentation analysis. However, a considerable increase in the expression of the p53 gene and correlated with the dosages increase. However, the p53 expression was altered upon applying the probiotics, while some histological changes were detected, but no DNA fragmentation was detected. The seriousness of EtBr on the organism's health is conditional with the applied doses. Probiotics were not luckier than EtBr; it did not provide expected health benefits. This unexpected action of probiotics may be due to the used dose and how to use it. Further analysis of both histological and molecular aspects using multiple controls and integrative experiments is required to explain probiotics' paradox effect versus the EtBr effect on mammalian cells and tissues. Keywords: EtBr, Probiotic bacteria, genotoxicity, q-PCR, DNA fragmentation.