Safety in space: synthetic hibernation could provide protection against cosmic radiation

This is another glimpse of the future: astronauts could be put into artificial hibernation and in this state be better protected from cosmic radiation. Currently, there are already promising approaches to address these considerations.

An international research team led by the biophysics department of the GSI Helmholtzzentrum in Darmstadt has now found decisive insights into the possible benefits of artificial hibernation for radiation resistance. Research partners from Germany, Japan, Italy, the United Kingdom and the United States recently published their results in Scientific reports.

Scientists call the state in which hibernating animals enter torpor. In this state, the vital functions of an organism are reduced: body temperature is lowered, metabolism is reduced and bodily functions such as heart rate and respiratory rate or oxygen consumption are significantly slowed down.

At the molecular level, gene activity and protein biosynthesis are also reduced at a slower rate. In the study published today on synthetic torpor (i.e. a type of artificially produced hibernation) and protection against ionizing radiation, scientists found biological effects suggesting that synthetic torpor increases radiation resistance. A proof that can be very useful in the long term for astronauts.

Space radiation is recognized as one of the major health risks of human space exploration. The harmful effects of space radiation pose a major challenge, especially for future long-term missions. The majority of the radiation dose absorbed by crews in manned interplanetary missions is produced by galactic cosmic radiation (GCR), high-energy charged particles, including densely ionizing heavy ions, produced in distant galaxies.

The energy of these particles is so high that the shielding of the spacecraft cannot stop them and leads to exposure rates more than 200 times greater than the radiation background on Earth over a very long period. For these reasons, radiation countermeasures for future missions are under consideration.

“The links between torpor and radioresistance represent a very innovative research approach. Our results indicate that synthetic torpor is a promising tool to improve the radiation protection of living organisms during long-term space missions. It could therefore be a ‘an effective strategy to protect humans when they explore the solar system,’ summarizes Professor Marco Durante, head of the GSI’s biophysics division.

We already know that animals that hibernate naturally acquire radioresistance in this state. However, the recent study is so important because it is the first time that a hibernation-like biological state has been induced in a non-hibernating animal (rat) and radioresistance to high-energy heavy ions could be proven.

In experiments at Gunma University’s Heavy Ion Medical Center in Japan, accelerated carbon ions were used to simulate radiation in space. The other in vitro cell experiments were performed on the GSI/FAIR campus in Darmstadt and were part of the FAIR Phase 0 experimental period.

The main results of the research team after irradiation and induction of synthetic torpor proved the hypotheses: Synthetic hibernation can have protective effects on a lethal dose of C ions. In addition, synthetic hibernation reduces the tissue damage caused by total body irradiation.

Additionally, GSI scientists were able to characterize the underlying mechanism in their studies of rat tissue cells. They showed that a lower oxygen concentration in the tissues (hypoxia) and a reduced metabolism at low temperature (hypothermia) could be two important factors in the prevention of cell damage. Immunohistological analyzes indicated that the synthetic torpor spares the tissue from energetic ion radiation. Additionally, changes in low-temperature metabolism could also affect DNA repair.

Much research is still needed to study and better understand the radioprotective effect of synthetic torpor in organs. Currently, it is technically not possible to hibernate a human in a safe and controlled manner. However, research is progressing. It is only recently that the neural pathways that control torpor have been unveiled. Now the current post adds another important element.

The Scientific Director General of GSI and FAIR, Professor Paolo Giubellino, points out that the FAIR International Acceleration Center, currently under construction at GSI, will provide unique opportunities for research in the field of cosmic radiation.

“Already today, the GSI facility is capable of producing beams of heavy nuclei as they occur in cosmic radiation. At FAIR, experiments with a much wider range of particle energies and intensities will be possible. This will allow researchers to study the effects of cosmic radiation on humans and on technical instrumentation, which are fundamentally necessary to make human missions to Mars possible. I am very pleased that the European Space Agency ESA has been cooperating with FAIR for many years to foster this area of ​​research.