Exposure to radiation during deep-space missions might not cause as much damage to astronauts’ muscles as once thought – but, it could enhance the effect of microgravity on their bones.
While scientists have suspected that radiation may exacerbate both muscle and bone loss in microgravity conditions, a new study found that this may not be the case.
Using a simulated space environment, researchers discovered that radiation alone does not have an effect on muscle loss; it does, however, amplify the negative effects on the bones.
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Exposure to radiation during deep-space missions might not cause as much damage to astronauts’ muscles as once thought – but, it could enhance the effect of microgravity on their bones
SPACE PUTS IMMUNE SYSTEM ON DEFENSE
This revealed that some protein concentrations remained the same across the study, while others did change, but quickly returned to normal.
Others, however, recovered more slowly.
The results suggest the body likely is not equipped with the mechanisms to specifically cope with the effects of space flight, prompting it to ‘turn on all possible defense systems.’
‘Bone is a very dynamic tissue,’ said Henry J Donahue, PhD, chair of the Department of Biomedical Engineering and School of Engineering Foundation Professor at the VCU School of Engineering.
‘As more demands are put on it, it gets bigger to meet those demands.’
With fewer demands, on the other hand, as in microgravity, ‘your body won’t waste time building bone,’ the researcher says.
In the new study, researchers examined mice under conditions similar to microgravity – in which their movements were restricted – and mice expose to simulated space radiation.
While microgravity alone was found to affect both the bones and muscles, radiation on its own did not.
‘Radiation plus microgravity amplifies the negative effect of microgravity on bone, but does not affect muscle loss,’ Donahue said.
‘It’s as if exposure to radiation itself doesn’t affect bone, but it makes it more sensitive to the negative effects of microgravity.’
According to the researchers, the effects of microgravity on the bones and muscles are similar to that which happens as people get older.
And, as people live longer due to recent breakthroughs in medicine, these issues are a growing concern.
Using a simulated space environment, researchers discovered that radiation alone does not have an effect on muscle loss; it does, however, amplify the negative effects on the bones. Stock image
Older people ‘fall more, they break their bones more,’ Donahue said.
‘That’s a huge problem. Understanding the relationship in microgravity between bone and muscle has relevance to the effect of aging on muscle and bone.’
The researchers plan to work to determine if microgravity and radiation can bring on any genetic changes as well.
HOW SCOTT KELLY’S DNA CHANGED IN SPACE
This is according to the first results of NASAs ground-breaking ‘Twins Study’ which looked at difference between astronauts Scott and Mark Kelly.
While Scott Kelly lived aboard the International Space Station for 340 days, his identical twin, Mark, remained on Earth.
Among the many findings, the study has so far revealed that:
Preliminary results from NASA’s Twins study on Scott and Mark Kelly show that the body responds immediately to the space environment, with gene expression acting ‘like fireworks taking off’ to switch thousands of genes on and off
- Scott’s telomeres – the caps at the end of each chromosome – lengthened while in space
- Telomeres are key to protecting DNA from damage and tend to shorten with age
- Interestingly, Scott’s telomeres shortened again once he was back on Earth
- Nasa say that Scott’s lengthening telomeres are linked with his diet and exercise routine on the station
- The ratio of two groups of gut bacteria shifted while Scott was in space, likely due to his change in diet
- His gut bacteria levels returned to normal once he was back on Earth.
- Nasa research has spotted hundreds of diverging genetic mutations in Scott and Mark’s genomes.
- The research team speculate that a ‘space gene’ could have been activated while Scott was in orbit
Other studies this year have found that the effects of space on the body can be dramatic.
The preliminary results from NASA’s Twins study on Scott and Mark Kelly, for example, show that the body responds immediately to the space environment, with gene expression acting ‘like fireworks taking off’ to switch thousands of genes on and off.
And, a study on Russian cosmonauts revealed that space flight causes the immune system to ‘turn on all possible defense systems’ in the face of the unfamiliar threat, leading to significant changes all throughout the human body, from the organs down to the tissues and cells.