High-energy radiation can be very dangerous. Besides a long-term increased risk of cancer due to DNA damage, a high enough dose of radiation can cause lethal damage to multiple systems in the body, especially the gastrointestinal tract and the immune system. Finding new ways to treat or prevent damage from radiation would be very helpful for improving the safety of space travel, nuclear energy, and radiotherapy for cancer.
In this study, some mice exposed to a typically lethal dose of radiation survived without ill effects, thanks to certain microbes in their gut. Transferring these microbes to other mice helped those mice survive radiation as well, and even just the metabolites that the bacteria produced were helpful for protecting the cells in the body most affected by radiation.