A mathematical model of enhanced DNA repair effect on cell survival in radiation-induced adaptive responses

DNA repair is one of the important factors to understand the mechanisms of radiation-induced adaptive responses. It is known that conditioning dose enhances the DSB repair performance temporally. However, the effects of the enhanced DSB repair on cell level responses have not been clear. In the present study, we proposed a mathematical model for analysis of the enhanced DSB repair effect in the adaptive response. Our model is a population of cell model which consists of three parts, inductions of cellular damage based on target theory, repair of cellular damage, and survival decision. The cell model has some active targets that are inactivated by radiation. The number of inactivated targets at each time step is determined according to a Poisson distribution. Some inactivated targets are turned into active targets at each time step based on DNA repair rate. The cell model shows “survival state” or “death state”. When the number of inactivated targets is larger than a certain value, the cell state is switched from “survival state” to “death state”. Survival fraction of our model is calculated as the number of survival state cells divided by the number of all cells. We calculated the survival fractions at control and adaptive condition using normal and enhanced DNA repair rates. We will discuss the usefulness of our model for investigating the effects of DNA repair system on cell survival in adaptive response.MICROS 2017 17th International Symposium on Microdosimetr