Response of cultured IEC-17 normal rat intestinal epithelial cells to X radiation.

The growth parameters and radiosensitivity of normal rat intestinal epithelial cells, IEC-17, were studied. The cells were cultured by standard methods and exposed to an array of doses (1-12 Gy) of 250 kVp X rays. The survival curves generated exhibited no initial shoulder and were bimodal. The Do of the first component was about 0.2 Gy and the second component. 5.0 Gy. The ability of this cell line to repair sublethal lesions was examined by fractionation studies; repair was completed within 60 min after the first dose. When Chinese hamster ovary (CHO) cells were grown under the same conditions used for the IEC-17 cells and then irradiated with single doses, a typical survival curve with a Do of 1.4 Gy was obtained. The survival curves obtained for the IEC-17 cell line are consistent with the response of a morphologically distinct single population containing two functionally separate types of cells.