Differentiation and delayed cell death in embryonal stem cells exposed to low doses of ionising radiation.

Embryonal stem cells have been used to study the effects of environmentally relevant doses of radiation on cell death and differentation. The ES cells were found to have a greater than 60% chance of surviving the traversal of a single alpha-particle, the lowest possible dose of high linear energy transfer radiation a cell may receive. The ES cells appeared to possess the cell cycle checkpoints believed to prevent the transmission of the radiation damage. However, delayed effects were observed in the progeny. An increased incidence of apoptosis and haempoietic differentiation capacity was found to persist in the ES cell population over many cell divisions. Since both cell death and differentiation are known to play a key role in tissue kinetics, an ES cell model will provide a valuable and versatile cell system for studying the role of cell death and differentiation in the pathology of radiogenic diseases.