To determine the chronic low-dose radiation effects caused by α-particle radiation from 226Ra over multiple cell generations in CHSE/F fish cells and HaCaT human cells.Methods:
CHSE/F cells and HaCaT cells were cultured in medium containing 226Ra to deliver the chronic low-dose α-particle radiation. Clonogenic assay was used to test the clonogenic survival fractions of cells with or without being exposed to radiation from 226Ra.Results:
The chronic low-dose radiation from 226Ra does have effects on the clonogenic survival of CHSE/F cells and HaCaT cells. When CHSE/F cells were cultured in 226Ra-medium over 9 passages for about 134 days, the clonogenic surviving fractions for cells irradiated at dose rates ranging from 0.00066 to 0.66 mGy/d were significantly lower than that of cells sham irradiated. For HaCaT cells grown in medium containing the same range of 226Ra activity, the clonogenic surviving fraction decreased at first and reached the lowest value at about 42 days (8 passages). After that, the clonogenic survival began to increase, and was significantly higher than that of control cells by the end of the experimental period.Conclusion:
The chronic, low-dose high LET radiation from 226Ra can influence the clonogenic survival of irradiated cells. CHSE/F cells were sensitized by the radiation, and HaCaT cells were initially sensitized but later appeared to be adapted. The results could have implications for determining risk from chronic versus acute exposures to radium.