宇宙飞行能延长微型蠕虫的寿命

The effect of spaceflight on a microscopic worm -- Caenorhabditis elegans (C. elegans) -- could help it to live longer. The discovery was made by an international group of scientists studying the loss of bone and muscle mass experienced by astronauts after extended flights in space. The results of this research have been published July 5 2012, in the online journal Scientific Reports.

Dr Nathaniel Szewczyk, from The University of Nottingham, was part of the ICE-FIRST project which involved scientists from Japan, France, the US, and Canada. They discovered that spaceflight suppressed accumulation of toxic proteins that normally accumulate within aging muscle. They also discovered a group of genes that are expressed at lower levels during spaceflight. When the expression of these same genes were lowered in worms back on Earth the worms lived longer.

Dr Szewczyk, an expert in muscle metabolism, said: "We identified seven genes, which were down-regulated in space and whose inactivation extended lifespan under laboratory conditions."

How do these genes play a role in longevity control? Dr. Szewczyk said: "We are not entirely certain, but it would appear that these genes are involved in how the worm senses the environment and signals changes in metabolism（新陈代谢） in order to adapt to the environment. For example, one of the genes we have identified encodes insulin which, because of diabetes, is well known to be associated with metabolic control. In worms, flies, and mice insulin is also associated with modulation（调整） of lifespan."

What could this mean for space travellers? He said: "Well, most of us know that muscle tends to shrink in space. These latest results suggest that this is almost certainly an adaptive response rather than a pathological one. Counter-intuitively, muscle in space may age better than on Earth. It may also be that spaceflight slows the process of aging."

Dr Szewczyk's role was to provide expertise in the culturing of worms in CeMM -- a special liquid food for worms. Dr Szewczyk transported the samples to and from the Russian launch site and ran a series of 'health' checks to ensure that the tiny astronauts were fit for flying. On their return he helped with the analysis of the data.