Buff house mice may cease astronauts from shedding bone and muscle mass

Pablo Tucker
September 9, 2020

"In microgravity, you mimic the muscle loss that occurs in people who are bedridden".

The study published Monday in the journal Proceedings of the National Academy of Sciences. NASA astronauts Drew Morgan, Christina Koch and Jessica Meir, who participated in the experiment while it was on the space station, are included as authors and investigators on the study.

The 40 female mice, provided by the nonprofit Jackson Laboratory in ME, were genetically manipulated for muscle growth in an experiment to better understand how zero gravity affects the human body.

"Hence", the researchers wrote, "blockade of myostatin/activin A signaling by treatment with the ACVR2B/Fc decoy receptor can dramatically increase bone mass even in the setting of microgravity and, furthermore, can protect against bone loss caused by microgravity".

The 40 mice used in the research were carried aboard a SpaceX mission earlier this year. During the study, researchers sent 40 black mice to the International Space Station, long back in December 2019.

The untreated wild mice in space returned results that were as expected - in their 33-day jaunt, they lost between 8 and 18 percent of their muscle mass, and between 8 and 11 percent of their bone mineral density.

EMILY GERMAIN-LEE: That would be a miracle for a person either with primary bone disease, primary muscle disease or a combination.

Some mighty mice have overcome one of the major obstacles to interplanetary space flight: muscle and bone loss. Of particular interest were the mice receiving doses of ACVR2B/Fc, a compound that inhibits both MSTN and activin A, which work together to limit muscle growth.

"Again then, we confirmed that mice during which we deleted the myostatin gene had dramatic will increase in muscle mass all through the physique, with particular person muscular tissues rising to about twice the traditional measurement", Lee, a geneticist now on the Jackson Laboratory for Genomic Medication in Farmington, Connecticut, informed Area.com.

The mouse on the right has been engineered to have four times the muscle mass of a normal lab mouse.

After returning to Earth, mice receiving the receptor treatment also showed an enhanced recovery of muscle mass. This was compared with the control mice that were not given the treatment upon returning to Earth.

A team led by Dr Se-Jin Lee of the Jackson Laboratory added 40 young female black mice to the cargo of a SpaceX rocket sent to the ISS late previous year.

The results get even more interesting with the ACVR2B/Fc mice. Both are affiliated with the University of CT. Dr. Germain-Lee is a pediatric endocrinologist at Connecticut Children's Medical Center and a professor of pediatrics at the University of Connecticut's School of Medicine.

LEE: They lost a substantial amount of bone in space.

At the same time as the mice were aboard the ISS, similar groups were maintained here on the ground, in the same environmental conditions as the space station: everything was the same, except for the microgravity.

The findings hold promise for preventing muscle and bone loss in astronauts on prolonged space trips like Mars missions, as well as people on Earth who are confined to bed or need wheelchairs.

The exercise countermeasures astronauts use, which include two hours of resistance training and cardiovascular workouts, may not always be possible during long-term spaceflight.

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