Radiation sensitivity of 9L gliosarcoma cells at different oxygen pressures

Monolayer cultures of 9L gliosarcoma cells received radiation doses of 0-1750 ret at oxygen pressures ranging from 50 to 545 mmHg. Growth inhibition, which could be demonstrated in all radiated cell cultures, was most pronounced in those receiving the highest dose of radiation. There was no relationship between the radiation sensitivity of the cells and the oxygen pressure of the fluid media of the cell cultures at the time radiation was administered. Cells subjected to the lowest oxygen tensions (50-52 mmHg) did not grow whether they had received radiation or not. The technical difficulty of removing oxygen from tissue culture media is described. Possible points of significance in the findings of this study are discussed with regard to previous observations on the radiosensitivity of the 9L tumor model, current concepts in radiobiology, and implications for future studies of human tumors in cell culture.