美国国家公共电台 NPR Mighty Mice In Space May Help Disabled People On Earth : Shot（在线收听）

DAVID GREENE, HOST:

Now the story of some very unusual mice. They are back on Earth after a month on the International Space Station. And what scientists are learning from these animals could eventually help astronauts and other people with disabling bone and muscle diseases.

NPR's Jon Hamilton has the story of two researchers, a married couple, who sent their science into space.

JON HAMILTON, BYLINE: At the Kennedy Space Center in Florida, a SpaceX rocket is about to launch. And among the crowd of onlookers are two very anxious scientists.

SE-JIN LEE: Getting close to the two-minute warning.

HAMILTON: Dr. Se-Jin Lee studies muscles. His wife, Dr. Emily Germain-Lee, studies bones.

EMILY GERMAIN-LEE: I feel like our heart and soul is going up in that thing, you know? I'm, like, so nervous.

HAMILTON: Both scientists have a huge stake in an experiment packed inside the spacecraft.

LEE: We're past 32.

GERMAIN-LEE: All right.

HAMILTON: The experiment involves 40 mice that will spend more than a month in near-zero gravity. Usually, that causes bones to weaken and muscles to melt away.

GERMAIN-LEE: Here we go.

HAMILTON: But Emily and Se-Jin are hoping that won't happen with these mice, assuming they make it into space.

UNIDENTIFIED PEOPLE: Five, four, three, two, one.

GERMAIN-LEE: Oh. Oh. Oh, my God. Oh.

HAMILTON: It took the scientists 20 years to get the mice from lab to launchpad, but their story really begins in the late 1970s.

GERMAIN-LEE: We met when I was 18, and we were bio-chem majors in college together.

HAMILTON: At Harvard. They clicked. And early on, Emily had big dreams about what she and Se-Jin might accomplish.

GERMAIN-LEE: Wouldn't that be amazing if one day we worked on some project together that had incredible meaning and helped people and, like, all the stuff that you'd think a teenage kid would say.

HAMILTON: The couple went to medical school together at Johns Hopkins in Baltimore. She specialized in kids with rare bone disorders. He focused on muscle growth. They got married, had a son. And in the late 1990s, Se-Jin Lee got kind of famous. The reason was a bulked-up rodent known as Mighty Mouse. He showed me an example when I visited his lab in 2006.

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LEE: This was one that I've actually engineered. It has about four times the muscle mass of normal mice.

HAMILTON: Ordinarily, myostatin limits the growth of muscles. Get rid of that protein, and you get the mouse version of Arnold Schwarzenegger.

LEE: If you open up the mouse and actually look at the muscles, it is just really unbelievable, right? These animals are almost getting to the point where they don't really look like mice.

HAMILTON: Se-Jin thought his discovery might help people with diseases that weakened muscles. So he began looking for a drug that could block myostatin. Meanwhile, Emily was treating children with diseases that affected their bones, and she noticed that weak bones could lead to weak muscles.

GERMAIN-LEE: My bone patients don't escape muscle loss because they have large periods of time where they can't move or a whole lifetime where they're wheelchair-bound.

HAMILTON: Emily says it also works the other way.

GERMAIN-LEE: Any muscle disease leads to weakness. And any weakness leads to bone fragility eventually.

HAMILTON: At home, Emily and Se-Jin talked a lot about muscle and bone. And they realized a drug that could strengthen both might help a lot of people - kids with muscular dystrophy or brittle bone disease, cancer patients, patients with hip fractures and older people who had simply grown frail.

Eventually, Se-Jin identified a potential drug. It's a substance that affects not only myostatin, but also other proteins involved in bone growth. Emily wanted to test the drug on mice with brittle bones.

GERMAIN-LEE: I said, oh, my gosh, I really have to try this. And Se-Jin said, sure. And those were the first set of experiments we actually physically did together.

HAMILTON: The experiments worked. The mice developed stronger bones and stronger muscles. And Se-Jin saw a chance to revive an idea he'd been pursuing for two decades. It involved astronauts.

LEE: So for the astronauts in space, you know, they have lots of health things that they need to be thinking about, but certainly at the very top of that list would be muscle loss and bone loss.

HAMILTON: Without gravity, a person can lose up to 20% of their muscle mass in less than two weeks. By this time, Se-Jin and Emily had moved to the University of Connecticut School of Medicine. Emily works at Connecticut Children's Medical Center. Se-Jin has an appointment at the Jackson Laboratory. And not long after he arrived, Se-Jin got a chance to send his mighty mice to the International Space Station. They went up in December and came back last week.

LEE: Question is, will they lose any of that muscle mass? And then, if they do lose, then will they lose at the same rate as normal mice? Will they end up at the same place as normal mice? Will they be somewhat protected and so forth?

HAMILTON: But Se-Jin and Emily also sent up some other mice. They're normal rodents that received the drug that builds both muscle and bone, at least on Earth. It will take months for Se-Jin and Emily to know for sure whether they've figured out how to maintain muscles without gravity, but the couple says preliminary results look promising. Jon Hamilton, NPR News.