Mice are a common laboratory animal for pre-human testing. Everything from drugs to medical treatments to surgeries have been tested on mice, and the effects of spaceflight are no exception. Animals such as Laika the dog and Rhesus monkey Albert 1 have had their own test flights, but mice offer an easy alternative when there’s not much extra room on a spacecraft.
In a recent study, mice flown on the space shuttle Atlantis were shown to have developed early signs of liver disease. Could humans in space exhibit the same symptoms? “Prior to this study we really didn’t have much information on the impact of spaceflight on the liver,” said the study’s lead author Karen Jonscher, PhD, an associate professor of anesthesiology and a physicist at CU Anschutz. “We knew that astronauts often returned with diabetes-like symptoms but they usually resolved quickly.”
“We saw the beginning of nascent liver damage in just 13.5 days,” Jonscher said. “The mice also lost lean muscle mass. We have seen this same phenomenon in humans on bedrest — muscles atrophy and proteins break down into amino acids. The question is, how does that affect your liver?”
Space medicine is a growing field, matching the growth of the private space industry. Until recently, the medicine has been focussed on the cardiovascular, respiratory, and nervous systems, with a major focus on how microgravity affects muscles and bones. Metabolism definitely changes in space, and with diabetes like symptoms exhibited by astronauts, the liver has become a focal point.
With longer term missions on the horizon, specifically to Mars, this has become a pressing issue. How will the astronauts respond to the longer flight? If they do suffer unexpected damage, will it cause problems for the mission? Human safety is space is just as important as the science and engineering that take us there. If we can’t keep people alive and healthy as we explore the frontiers, is our technology really advanced enough to do it?
The field of space medicine has a lot of work ahead.