Artificial gravity reduces spaceflight's health toll in fruit fly tests
Microgravity wreaks havoc on the bodies of astronauts, which is bad news given humanity’s space-bound ambitions. A NASA experiment housing fruit flies on the International Space Station has now shown that artificial gravity can help reduce some of those health problems.
Humans, and indeed all life on Earth, evolved to thrive under the conditions on this planet, and of course gravity is a big factor. Our circulatory, digestive and central nervous systems all rely on fluids flowing downwards naturally, and our muscles and bones maintain a base level strength simply by resisting gravity every second of our lives.
So when you take humans out of that environment, it takes a toll on their biology. Astronauts’ faces are known to become puffy, their vision blurs, the heart weakens, muscles atrophy and bones lose mass. As such, they have to spend hours every day exercising vigorously while in space, and face long-term health problems even after returning to Earth.
With humans set to return to the Moon by 2024, and hopes of setting foot on Mars in the nearish future, finding ways to mitigate the damage from periods in microgravity is increasingly important. Whether artificial gravity can help reduce the effects is one of the key questions, and NASA has now investigated using fruit flies.
The insects were sent to the ISS, where they were tested in a device that could keep flies under different gravity levels. One group was exposed to the microgravity conditions natural to low-Earth orbit, while another experienced artificial gravity produced by spinning the enclosure in a centrifuge. A third group stayed on Earth to act as a control.
After three weeks in space, the fruit flies were returned to Earth and comprehensively studied, including observing their behavior, cellular changes in their brains, modifications to their gene expression, and how they aged after their return.
Both groups of spacefaring flies showed signs of changes in metabolism, oxidative stress in their cells, and negative neurological impacts. However, those that had been kept under artificial gravity appeared to be protected from some neurological changes, such as loss of neurons, changes to numbers of glial cells, oxidative damage, and cell death.
The microgravity flies also had a harder time readjusting to gravity after their return to Earth. They performed worse at a climbing test, and aged faster than either other group. While flies and humans are very different creatures, the team says that this experiment suggests that artificial gravity could help reduce the health problems in astronauts caused by microgravity conditions. This could be paired with special gravity-simulating spacesuits or centrifuges that make exercising in space more Earth-like.
“Microgravity poses risks to the central nervous system, suggesting that countermeasures may be needed for long-duration space travel,” said Dr. Janani Iyer, an author on the study. “As we venture back to the Moon and on to Mars, reducing the harmful effects of microgravity will be key to keeping future explorers safe. This study is a step in the right direction to explore the protective effects of artificial gravity in space and to understand the adaptation to Earth conditions after returning from space.”
The research was published in the journal Cell Reports.