Modification of genotoxicity of radiation by post-irradiation treatment with caffeine

The effect of caffeine during post-irradiation growth period on survival, gene conversion, back mutation, aberrant colony formation (ACF) and mitotic crossing over (MCO) was investigated in the diploid yeast strain Saccharomyces cerevisiae D7. The presence of caffeine in growth media reduced the radiation-induced cell killing and the frequency of all the genetic end points except MCO. The increase in MCO frequency might be related to the enhanced cell survival brought about by caffeine. It is suggested that post-irradiation division delay introduced by caffeine may alter the post-irradiation repair processes and may help the process of recovery by error-free repair pathways.