Abstract
Radiation generates reactive oxygen species that interact with cellular molecules. We investigate the effect of hydrogen peroxide compared to X-ray using repair proficient chicken DT40 cell and repair deficient DT40 cells (RAD54-/-, KU70-/-, RAD54-/-/KU70-/-). Repair proficient normal DT40 and KU70-/- cells were resistant to low dose of hydrogen peroxide (under 5μM) but RAD54-/- and RAD54-/-/KU70-/- cells were sensitive to. At higher dose of hydrogen peroxide (5~1000μM), both normal DT40 and KU70-/- cells had a huge tail of survival curve. Homologous recombination repair of DSB is very important for biological effects of hydrogen peroxide, suggesting that hydrogen peroxide make only SSB but this become DSB in S phase. Effect of oxygen radical might be not similar to ionizing radiation.
