By Marcia Dunn

Bulked-up, mutant "mighty mice" held onto their muscle during a monthlong stay at the International Space Station, returning to Earth with ripped bodybuilder physiques, scientists reported Monday.

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 a bed or need wheelchairs.

A research team led by Dr. Se-Jin Lee of the Jackson Laboratory in Connecticut sent 40 young female black mice to the space station in December, launching aboard a SpaceX rocket.

In a paper published in the Proceedings of the National Academy of Sciences, Lee said the 24 regular untreated mice lost considerable muscle and bone mass in weightlessness as expected — up to 18%.

But the eight genetically engineered "mighty mice" launched with double the muscle maintained their bulk. Their muscles appeared to be comparable to similar "mighty mice" that stayed behind at NASA's Kennedy Space Center.

In addition, eight normal mice that received "mighty mouse" treatment in space returned to Earth with dramatically bigger muscles. The treatment involves blocking a pair of proteins that typically limit muscle mass.

A SpaceX capsule brought all 40 mice back in good condition, parachuting into the Pacific off the California coast in January. Some of the ordinary mice were injected with the "mighty mice" drug after returning and quickly built up more muscle than their untreated companions, Lee said.

The scientists completed the experiment just as the coronavirus was hitting the U.S.

"The only silver lining of COVID is that we had time to write it up very intensively" and submit the results for publication, said Dr. Emily Germain-Lee of Connecticut Children's Medical Center, Lee's wife who also took part in the study. Both are affiliated with the University of Connecticut.

While encouraged by their findings, the couple said much more work needs to be done before testing the drug on people to build up muscle and bone, without serious side effects.

"We're years away. But that's how everything is when you go from mouse to human studies," Germain-Lee said.

Lee said the experiment pointed out other molecules and signaling pathways worth investigating — "an embarrassment of riches ... so many things we'd like to pursue." His next step: possibly sending more "mighty mice" to the space station for an even longer stay.

Three NASA astronauts looked after the space mice, performing body scans and injections: Christina Koch and Jessica Meir, who performed the first all-female spacewalk last fall, and Andrew Morgan. They are listed as co-authors.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.

Share:
More In Science
Major Cold Snap Settles Across Much of the U.S.
It's a painfully cold week across a large portion of the U.S. with more than 185 million Americans experiencing below-freezing temperatures on Monday and 10 million of them dealing with dangerous sub-zero temps.
New Study Shows Chatbots Help Prevent Eating Disorders
Ellen Fitzsimmons-Craft, assistant professor of psychiatry at Washington University School of Medicine, joins Cheddar News to discuss how chatbots can help prevent eating disorders and the research that uncovered these findings.
Why The Human Shoulder Is A Design Disaster
Shoulder injuries are one of the most common orthopedic injuries – and they're also one of the most commonly ignored. But chimpanzees, with whom we share nearly 99% of our DNA, don’t encounter the same issues we do. So why are human shoulders such a design disaster? Well, we can trace the answer back to a very particular moment in our evolution.
Nurses Call For Protection For HealthCare Workers
As the Omicron variant continues to sweep across the country. The US Supreme Court is expected to hear arguments at the end of this week on whether or not the Biden administration can force private companies to vaccinate or test millions of their employees. In addition, the National Nurses United has spearheaded legal action to protect nurses and health care workers, patients, and the public while on the job. President of the National Nurses Union, Zenei Cortez, joined Cheddar to discuss more.
Pear Therapeutics CEO on How Its Apps Work for Conditions Like Addiction
Digital medical care provider Pear Therapeutics rang the closing bell on the Nasdaq Friday and President and CEO Dr. Corey McCann, joined Cheddar to talk about how the company plans to grow the business of software-based therapeutics and how the first FDA authorized prescription digital therapeutics company will go about treating illnesses like insomnia and addiction. "These really are pieces of software. In many cases, they're apps and in the cases of our addiction products, these are based on something called cognitive behavioral therapy or CBT," he said. "These products change the patient's brain circuitry to help them be abstinent, to help them stay in treatment, and that's exactly what we see in randomized clinical trials and that's what we see in the real world." He also addressed the ongoing mental health crises brought on by the pandemic. **copy updated to remove IPO information as Pear Therapeutics went public in December**
Virgin Orbit Goes Public One Week Before 'Above the Clouds' Space Mission
Satellite launch service Virgin Orbit has gone public on the Nasdaq via a SPAC merger with NextGen Acquisitions with a valuation of about $3.2 billion. CEO Dan Hart joined Cheddar's "Between Bells" from in front of his LauncherOne rocket in New York City's Times Square to talk about what's next after the IPO, an upcoming "Above the Clouds" mission to deliver commercial and national security payloads, and the benefits of their rockets being launched from commercial 747 aircraft. "We can launch anywhere in the world," he said. "There are almost 80 space agencies across the world, for instance, and about 10 of them have space launch. We can give them a space flight capability overnight by taking a runway and turning it into a spaceport."
Cheddar Climate: The Fight for Change 2021 Year-End Special
The year 2021 saw numerous natural disasters around the world, including extreme heat and wildfires, rare deep freezes, and historic flooding. This year's United Nations COP26 conference was key for getting world leaders on board with emissions reductions and other climate-focused policies as the UN Secretary-General said the agency's report on global warming is a 'code red for humanity.' In the U.S., President Joe Biden has focused most of his domestic agenda on slashing emissions and building climate-focused infrastructure. Guests from The Economist, UNC-Chapel Hill, Global Rescue, and more join Cheddar Climate's year-end special to discuss how the climate changed in 2021, and what to expect in 2022.
Little Otter Raises $22 Million Series A to Combat the Children's Mental Health Crisis
Digital mental health company Little Otter recently announced it closed a $22 million Series A round. Little Otter was founded in 2020 by a mother-daughter team, which based the company on the idea that a child's mental health can only be addressed by treating the whole family through technology available to everyone. Little Otter CEO and co-founder Rebecca Egger and her mother, Little Otter Chief Medical and Scientific Officer and co-founder Dr. Helen Egger joined Cheddar News' Closing Bell to discuss.
Load More