Without gravity from Earth, muscles and bones tend to weaken quickly. To combat this, astronauts usually need to spend two hours per day exercising. Now, however, researchers have found that an experimental drug may be able to prevent muscle and bone loss while in space- something that may enable astronauts to spend more time there safely.
For the study, a research team from the Jackson Laboratory in Connecticut sent 40 young female black mice to the space station in December via a SpaceX rocket. While 24 of the mice were untreated, eight were genetically engineered to have double the musculature of regular mice prior to liftoff. A further 8 received an injection during their time in space that inactivated two substances in the body called myostatin and Activin-A, known to typically limit the growth of muscle and bone. All mice stayed in space for a month before being parachuted back down to Earth in January.
While 24 of the regular, untreated mice lost up to 18% of their muscle and bone mass, the 16 mice who were either genetically engineered to have double the normal rates of muscle, or injected with the drug, maintained their musculature. What’s more, mice injected with the drug after space flight back on Earth were better able to rebuild muscle mass than untreated counterparts.
Although the findings may pave the way for a new drug that could enable astronauts to spend longer in space, the researchers warn that the drug has only so far been shown to work on mice and that much more work is needed before it may be tested on humans too.
As such, the researchers say the next step is to send more mice to space for longer periods of time to more closely monitor and understand how the drug works.