Irradiation with HeNe laser can influence the cytotoxic response of HeLa cells to ionizing radiation

摘要

A monolayer of HeLa cells in plateau-phase of growth was exposed to He-Ne laser radiation either 5 min, 60 min or 180 min before $gamma@-irradiation. It has been shown that in the case of a 5-min interval between the two types of irradiations the survival curve was practically identical to the survival curve of the cells after $gamma@-irradiation only. In the case of He-Ne laser exposure 60 min before $gamma@-irradiation with doses of over 5 Gy, a fraction of more resistant cells was revealed: their D$-0$/ was twice as high as the D$-0$/ of the min population. A preexposure of cells to He-Ne laser 60 or 180 min before $gamma@- irradiation also changed the shape of the growth curves as compared to $gamma@-irradiated cells. It is proposed that the preexposure of cells to He-Ne laser radiation activates, in a subpopulation of cells, processes which speed up the repair of $gamma@-radiation damage. The possibility that the described phenomenon is an adaptive response of cells is discussed.