Risk assessment of space radiation during manned space flights

During a long-term exploration in space, astronauts will be constantly exposed to space radiation which contains various types of low dose-rate heavy particles. Although the fluxes of these heavy ions are very small, the heavy ions can cause severe biological effects including early effects and late effects. This short review will discuss the biological effects induced by space radiation and introduce a new anti-radiation agent we have developed. We synthesized a class of reactive oxygen species scavengers called GANRA-5 with lowly toxic but high radio-protective effect to both heavy ions and X-rays. GANRA-5 can protect cells from X-rays and carbon ions induced cell killing by significantly reducing the amount of free radical production therefor reduce double-strand breaks and genomic instability. In vivo, GANRA-5 can effectively protect the mice from the damage induced by X-rays irradiation by enhancing superoxide dismutase activities. In brief, GANRA-5 is potentially applicable in space flight.