Comparison of Radiation-Induced Chromatid Aberrations in the Testes and Bone Marrow of the Chinese Hamster

Cells from the testes and bone marrow of the Chinese hamster were sampled at 6 hours after the end of exposure to cobalt-60 gamma irradiation, and the number of chromatid-type aberrations was scored in an attempt to measure radiation sensitivity. By varying the dose, the radiation sensitivity (the number of single-hit breaks per cell per roentgen) was calculated to be 0.0015 for the bone marrow and 0.0041 for the testes. This indicated that the number of chromatid deletions observed in a somatic tissue may not reflect the number produced by the same dose of radiation in a reproductive tissue. The change in the chromatid breakage frequency as a function of time after irradiation was also measured. These results indicated that the number of chromatid aberrations observed in each of the two tissues was dependent on the time interval between irradiation and sampling of the cells. Ratios of the number of breaks in the chromosomes of the testes divided by those in the bone marrow had values ranging over time from 1.34 to 3.19. It was concluded that several different time intervals of sampling must be used to characterize the radiation sensitivity of any previously unmeasured tissue.