These Beefcake Mice have been engineered genetically and have been able to regain their muscle mass in space!

Let’s take a look at how microgravity works

Microgravity is a serious factor for us on earth. When a person has been in space for prolonged periods, say 6 months, their body will have a hard time recovering their muscle mass and bone density. That’s because the body isn’t constantly acting against gravity. So even if an astronaut were to return to earth and exercise for two hours daily, they will take months to recover their muscle mass, and recovering their bone density can take years.

This effect will be greatly amplified if astronauts were to go on a three year round trip to Mars. So in order to prevent that, scientists have been experimenting on mice.



They genetically engineered mice and had them spend 33 days aboard the ISS. The experiment concluded that these mice were able to retain more muscle and bone density than ordinary mice.

In their paper, the researchers wrote that they had engineered a protein called myostatin, which helps in regulating muscle growth. Mutations in the myostatin gene can produce something called myostatin-related muscle hypertrophy, can cause the test subjects to get mega beefcake muscling. It had been seen on cattle before.

For the experiment, the mice had been divided into five groups of eight mice each. Three of these groups were left untreated as their purpose was to serve as a control. Group 4 were injected with ACVR2B/Fc, a protein that slows or prevents myostatin signalling and activin A, and the final group were the actual subjects known as the Mighty Mice.

Those untreated lost about 8 to 18 percent of their muscle mass, and 8 to 11 percent of their bone density in those 33 days. The Mighty Mice, that started off with double the muscle mass of the ordinary mice, did not lose much mass. The experiment is far from over, but if they work around this, they can help with space travel and even provide treatments for diseases like osteoporosis.


(Cover: ScienceAlert)