The effect of oxygen on low-dose hypersensitivity and increased radioresistance in Chinese hamster V79-379A cells.
Chinese hamster V79 cells irradiated in air are hypersensitive to X-ray doses less than 0.5 Gy and show an increased radioresistance over the dose range 0.5-1 Gy (Marples and Joiner, Radiat. Res. 133, 41-51, 1993). Of considerable interest from both a mechanistic and clinical viewpoint is the response of hypoxic cells over this dose range. The data presented here indicate that hypoxic cells are also hypersensitive to low X-ray doses and exhibit an increased radioresistant response, albeit triggered at a somewhat higher dose (0.69 Gy, SEM +/- 0.18 Gy) than observed in oxygenated cells (0.5 Gy, SEM +/- 0.21 Gy). These data indicate that the triggering event for increased radioresistance may be independent of oxygen. As reported by others previously, the oxygen enhancement ratio was found to decrease with a decreasing X-ray dose.
Marples
B
B
Department of Medical Biophysics, British Columbia Cancer Research Centre, Vancouver, Canada.
Joiner
M C
MC
Skov
K A
KA
D000818:Animals; D015687:Cell Hypoxia; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004307:Dose-Response Relationship, Radiation; D010100:Oxygen / Q000502:physiology*; D011836:Radiation Tolerance
D010100:Oxygen