Effect of N-acetylcysteine on 12C6+ ion Irradiation-induced Lymphocytes DNA Damages and Immunity Changes in Mice

12 C 6+ heavy ion/N-acetylcysteine/DNA double-strand breaks/Immunity acute effects. The aims of present study are to estimate the biological risks to the immunity of mice exposed to hea vy ion radiation and to investigate the effect of N-acetylcysteine (NAC) on 12 C 6+ ion irradiationinduced lymphocyte DNA damage. Results showed that in the brine group, the levels of lymphocyte DNA damage and MN, thymocytes G2/M phase arrest and apoptosis percentages (except for activity of NK cells) were up at each time point. A time-response curve for MN and DNA damage appeared in the NAC group. We found that whole-body 12 C 6+ ion irradiation at a dose of 4 Gy could: induce lymphocyte DNA double-strand breaks (DSBs); immunocytes DSBs may lead to acute effects on immunity; and 200 mg/kg NAC showed significant protection against radiation harm. One of the challenges of space exploration is the biological effects from exposure to heavy ion radiation levels so e valuation of potential health effects from radiation exposure is important for the astronaut and terrestrial humans who are continuously and simultaneously exposed to numerous environmental radiations. Recently, it became more and more im portant to determine the time-effect relationship of radiation exposure when assessing human health risks. Most of th ese studies have been performed with irradiation of high doses, and they had less relation to medical protective effect on immunity of body exposed to irradiation. Moreover, there has been growing attention paid to changes in the immune system after irradiation. Numerous studies have demonstrated that the immune competence of irradiated human populations, as well as experimental models in the laboratory d ecline with increasing radiation dose of various radiation types. 1–3) Changes in immune function are also reported dur