Correlation between non-repairable DNA lesions and fixation of cell damage by hypertonic solutions in Chinese hamster cells.
In Chinese hamster HA-1 cells, killing induced by gamma-rays was enhanced by post-irradiation treatment with hypertonic solution (0.5 mol/l NaCl in phosphate buffered saline, pH 7.2) for 20 min. The initial DNA double-strand breaks (dsb) induced by gamma-rays were repaired during post-irradiation treatment with hypertonic solution. However, hypertonic treatment following gamma-irradiation enhanced the frequency of non-repairable dsb, as compared with the frequency after incubation at 37 degrees C following gamma-irradiation. Hypertonic treatment did not affect the initial half-time for rejoining of dsb. Hypertonic treatment did not enhance cell killing, nor did it enhance the non-repairable dsb when the irradiated cells were incubated at 37 degrees C for 2 h. These results suggest that fixation of gamma-ray-induced potentially lethal damage by hypertonic treatment results from inhibition of the rejoining of dsb.
Kosaka
T
T
Radiation Biology Laboratory, Institute of Physical and Chemical Research, Saitama, Japan.
Kaneko
I
I
Koide
F
F
D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects*; D003037:Cobalt Radioisotopes; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006982:Hypertonic Solutions / Q000494:pharmacology*
D003037:Cobalt Radioisotopes; D006982:Hypertonic Solutions; D004247:DNA