Essentially we need to operate with artificial gravity. The good news is that this is possible, except we have not been allowed to know.
A
new study from the Henry Ford Hospital has highlighted a potential
hazard for future space travelers – bad joints. An examination of the
tissues of rodents that orbited the Earth in a Russian spacecraft
revealed that the reduced load on their joints caused the breakdown of
cartilage and signs of arthritis-like degradation.
One
of the depressing facts about spending time in zero gravity is that it
is very hard on the human body. Even if protected from the hazards of
vacuum, heat, cold, or radiation, the lack of gravity can take a
terrible toll. Prolonged space flights, like the Mars missions
that will one day take place, can cause all sorts of medical problems,
including muscle atrophy, the loss of bone calcium, a weakened
cardiopulmonary system, impaired eyesight, and could even affect the immune system.
The
recent Henry Ford study raises the possibility that joint cartilage
might also be affected, because the body isn't carrying the usual load
that it does on Earth. The team led by head of musculoskeletal genetics
Jamie Fitzgerald emphasizes that there's no evidence that this is
actually happening to humans, but the effects of zero gravity on mice
does raise concerns.
Operating
under a US$100,000 NASA grant, the research involved sending six male
mice into space aboard Russia's unmanned BION-M1 biosatellite, which
orbited the Earth from April 19 to May 19, 2013. These pathogen-free lab
mice were 19 to 20 weeks old at lift off. Meanwhile, 15 control mice
back on Earth were kept in identical conditions, except that they were
under full gravity.
Analysis
of the tissues and gene expressions of the cartilage after 30 days in
space showed signs similar to those of osteoarthritis, indicating that
the tissue had broken down. The team believes that this is due to the
fact that though the mice could be seen getting exercise as they climbed
over one another in the spacecraft, their bodies weren't carrying the
weight load that they would have back on Earth. So the cartilage
couldn't maintain its integrity.
"We
do know that tissues of the musculoskeletal system – bone, muscle,
tendon, cartilage and ligament – are constantly subjected to 'loading'
everywhere on Earth," says Fitzgerald. "This comes from daily activities
like walking and lifting, and the action of gravity pulling down on the
musculoskeletal system. When that loading is removed due to
weightlessness and near zero gravity in space, these tissues begin to
degrade. The most dramatic example is the atrophy of muscle and
demineralization of bones that occurs during spaceflight.
"This
muscle and bone loss are reversed when the astronauts return to Earth.
What is interesting about cartilage is that it's a tissue that repairs
very poorly. This raises the important question of whether cartilage
also degrades in space. You may have some payload specialists and
experienced pilots who already have some degree of pre-symptomatic
cartilage damage at the time of their flight.
Because cartilage in humans doesn't readily repair, the return to Earth could potentially bring long-term health problems."
Because cartilage in humans doesn't readily repair, the return to Earth could potentially bring long-term health problems."
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