The effects of chronic, low doses of Ra-226 on cultured fish and human cells.
To determine the chronic low-dose radiation effects caused by α-particle radiation from (226)Ra over multiple cell generations in CHSE/F fish cells and HaCaT human cells.



CHSE/F cells and HaCaT cells were cultured in medium containing (226)Ra 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 (226)Ra.



The chronic low-dose radiation from (226)Ra does have effects on the clonogenic survival of CHSE/F cells and HaCaT cells. When CHSE/F cells were cultured in (226)Ra-medium over 9 passages for about 134 days, the clonogenic surviving fractions for cells irradiated at dose rates ranging from 0.00066 to 0.66mGy/d were significantly lower than that of cells sham irradiated. For HaCaT cells grown in medium containing the same range of (226)Ra 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.



The chronic, low-dose high LET radiation from (226)Ra 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.
Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada.
Xiaopei
X
Shi
Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada.
Colin
C
Seymour
Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada. Electronic address: mothers@mcmaster.ca.
Carmel
C
Mothersill
D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D005399:Fishes; D006801:Humans; D011883:Radium / Q000633:toxicity*
D011883:Radium
(226)Ra; chronic; low-dose radiation; surviving fraction; α particles