Worms reveal effects of long space voyages
"While it may seem surprising, many of the biological changes that happen during spaceflight affect astronauts and worms and in the same way," said Nathaniel Szewczyk, a physiologist at the University of Nottingham in the U.K., in a statement. He led the study published Wednesday in the journal Interface.
"Given the high failure rate of Mars missions, use of worms allows us to safely and relatively cheaply test spacecraft systems prior to manned missions."
Szewczyk and colleagues at Simon Fraser University in Burnaby, B.C., the University of Pittsburgh and the University of Colorado sent 4,000 microscopic Caenorhabditis elegans (C. elegans) worms aboard the Space Shuttle Discovery to the International Space Station in December 2006. The space station is located in low-Earth orbit at an altitude of 400 kilometres. The worms, which belong to a strain developed at Simon Fraser University, lived there for six months — twice as long as originally intended due to weather-related space shuttle delays, said Bob Johnsen, a researcher at Simon Fraser who co-authored the paper. Over that time, the worms produced roughly 12 generations of descendants.
The researchers had developed a system that automatically regulated the temperature, oxygen, relative humidity, and available food in their environment. They were monitored and measured daily by scientists from Earth using miniature cameras, with the help of grade and high-school students in Canada, the U.S. and Malaysia.
Scientists hope this means worms will allow them to understand the long-term biological effects of space travel, including hazards such as muscular deterioration and radiation exposure.
The recent experiment has already provided some insights — the worms' muscles did deteriorate in space, as human muscles do. But the worms moved as much as they do on Earth when they were fed, suggesting that their muscles deteriorated because they didn't need as much strength in low gravity, rather than because they were otherwise damaged by space travel.
The worms were just as active after 12 generations as they were in the first. That was good news because it countered scientists' worries that muscular decline would continue indefinitely and never plateau.
The researchers plan to release more results of the study soon, including their findings about how the worms' muscles repair themselves in space.
Johnsen said the Canadian researchers involved in the project are particularly interested in how the high levels of radiation in space affect the mutation of the worms' DNA. In fact, the worms belonged to a special strain that allows the researchers to track new mutations. Those studies were partly funded by the Canadian Space Agency, and the work is ongoing, Johnsen said.