Dimethyl sulfoxide, a potent oral radioprotective agent, confers radioprotection of hematopoietic stem and progenitor cells independent of apoptosis.

In mass casualty events involving radiation exposure, there is a substantial unmet need for identifying and developing an orally bioavailable agent that can be used to protect the hematopoietic stem cell pool and regenerate hematopoiesis after radiation injury. Dimethyl sulfoxide (DMSO), a free-radical scavenger, has shown therapeutic benefits in many preclinical and clinical studies. This study investigates the radioprotective effects of DMSO on oral administration. Single dose of oral DMSO administrated before irradiation conferred 100% survival of C57BL6/J mice receiving otherwise lethal as well as super-lethal radiation dose, with wide radioprotective time frame (from 15min to 4h). Oral DMSO not only protected radiation-induced acute hematopoietic stem and progenitor cell (HSPC) injury, but also ameliorated long-term BM suppression following irradiation in mice. Mechanistically, DMSO directly protected HSPC survival after irradiation in vitro and in vivo, whereas no radioprotective effect was seen in MLL-AF9-induced leukemia cells. Unexpectedly, DMSO treatment did not inhibit radiation-induced HSPC apoptosis, and the HSPC survival from Trp53-and PUMA-deficient mice after irradiation was also protected by DMSO. In conclusion, our findings demonstrate the radioprotective efficacy of oral DMSO. Given its oral efficacy and little toxicity, DMSO is an attractive candidate for human use in a wide variety of settings, including nuclear accidents and medical radiation.