Effect of radiation on UDS in the spleen cells in mice

The effect of different doses of ionizing radiation on the capability of spleen cells in repairing DNA damage by assaying UDS in these cells was reported. It was shown that 24 h after whole body X-irradiation with doses in a range of 0.5 to 6 Gy caused a depression of UDS in a dose-dependent manner, the dose-effect relationship being linear without a shoulder. Single whole body X-irradiation with smaller doses (25-25 mGy) resulted in an apparently different picture showing significant stimulation at 50 mGy (P < 0.05). Continuous low-level γ-irradiation at a dose rate of 5.4 mGy/6 h. d also caused stimulation of UDS in the splenocytes ( P < 0.02) at the end of 4 week-irradiation, with a cumulative dosage of 130 mGy. The experimental data demonstrated that larger doses may cause depression, while smaller doses may cause stimulation of the capability of excision repair of DNA in the splenocytes, and that the total dosage causing stimulation may be different with different dose rates