Human beings have evolved under the constant influence of the earth’s gravity. But space travel in microgravity becomes a real test for the body: muscles weaken, bones lose density, and radiation threatens to irreversibly distort DNA. To understand how space conditions affect the human skeleton, scientists from the Blue Marble Space Institute (BMSIS) conducted an experiment with mice on the ISS. The results were unexpected, and provided clues to the problem of bone mass loss in astronauts.
Astronaut mice and the mystery of bones
A team led by Rukmani Cahill sent a group of mice to the International Space Station for 37 days. Upon returning to Earth, their bones were examined using high-resolution 3D tomography. It turned out that microgravity destroys the skeleton not evenly: the femurs lost up to 18% of tissue, but the spine remained almost intact. This proved that the main enemy of bones in space is mechanical unloading, not radiation or stress.
“When the body doesn’t have to fight gravity, bones that used to carry the load start to ‘conserve resources,’” Cahill explains. However, the study also revealed a paradox: in the upper part of the femur, microgravity accelerated the transformation of cartilage into bone tissue. This can lead to premature closure of growth zones, limiting bone length – a previously unknown effect of spaceflight.
The most surprising discovery was the effect of habitat on bone health. A control group of mice that were on Earth in special 3D-structured mesh enclosures not only retained bone mass, but increased it. In contrast, mice in conventional cages showed a dramatic deterioration in bone health.
“The 3D cages mimic a natural environment – the mice were climbing, exploring the space, which increased the mechanical stress on their bones. It’s like a gym for rodents!” – joked the authors of the study. The conclusion is simple: activity and varied movement are critical for bone health, even on Earth.
What does this mean for people?
The study confirmed: to prevent bone loss in space, we need to recreate mechanical loading on the skeletal support areas. The ISS already uses simulators, but future missions to Mars will require innovative solutions, such as artificial gravity or customized exercise programs.
In addition, the discovery to accelerate bone formation may help treat osteoporosis or injuries. “We still don’t realize how much the human body depends on the familiar conditions of the Earth. Space is a unique laboratory for studying ourselves,” Cahill concludes.
Space experiments with mice prove a simple fact: sometimes it’s not a complicated technological trick that saves us, but a simple truth: movement is life.
We previously reported on how a way to prevent bone mass loss in space was found.
According to universetoday.com
