British worms launched into space

In November, 4,000 worms from the University of Nottingham (UK) flew into space on board the space shuttle Atlantis. The microscopic worms, Caenorhabditis elegans, which share much of their genetic material with humans, might help scientists better understand how to treat people who suffer from muscle deterioration due to space travel.

Nathaniel Szewczyk of the University's Institute of Clinical Research (Derby, UK) and colleagues from the United States and Japan had already established C. elegans as a good model for studying the effects of altered gravity in space (Adv. Space Res. 41, 807–815; 2008). Szewczyk and researchers from Nottingham and Tohoku University (Sendai, Japan) are now testing whether treating worms with RNAi that is targeted at specific proteases will help block muscle degradation in space.

In preparation for space travel, the researchers put the worms into a dormant state and stored them in special cell culture bags. After the worms reached the Japanese Experimental Module 'Kibo' at the International Space Station, they were brought out of their dormant state and exposed to the space station conditions for 4 days. The worms were then frozen again for the trip back to earth. Researchers in Derby will now study whether the RNAi managed to prevent or mitigate muscle degradation in the worms.

No oxygen, no problem for naked mole rats

In most mammals, oxygen deprivation, even for short periods of time, causes injury to the brain tissue and potential long-term damage. But the naked mole rat (Heterocephalus glaber), a small, subterranean rodent native to eastern Africa, seems to weather hypoxia quite well. Naked mole rats have drawn a good deal of scientific attention lately, as they possess a suite of unique characteristics presumed to be adaptations for surviving underground. They are extremely long-lived, with an average lifespan near 30 years, almost 10 times longer than that of a rat or mouse. They lack pain sensation in their skin, and perhaps most notably, they are resistant to cancer.

The most recent research has focused on their tolerance for low-oxygen conditions. John Larson and Thomas Park (University of Illinois, Chicago) found that neurons from naked mole rats continued to function, despite low or no oxygen, for much longer than did mouse neurons and were able to recover even after 30 min of oxygen deprivation (NeuroReport 20, 1634–1637; 2009).

Understanding the mechanism underlying hypoxia tolerance in naked mole rats may lead to better ways of treating brain injuries associated with oxygen deprivation in humans, such as stroke, heart attack and accidents like drowning.

Pain that overstays its welcome

For a short time after an injury, people usually become extra-sensitive to pain at the injury site. Even lightly touching the injured area can cause pain. In some cases, however, this hypersensitivity becomes chronic and lasts long after the injury has healed.

Now researchers led by Robert Edwards of the University of California, San Francisco School of Medicine have reported that a previously uncharacterized type of neuron might be at least partly responsible for this hypersensitivity caused by injury (Nature published online 15 November, 2009; doi:10.1038/nature08505). These neurons, known as unmyelinated, low-threshold mechanoreceptors (C-LTMRs), contain a protein called VGLUT3 that allows the C-LTMRs to send signals to other cells.

To further study VGLUT3, the research team developed mice that lacked VGLUT3. Both normal mice and the mice lacking VGLUT3 responded to most painful stimuli, such as heat and tail poking, in the same way. The researchers then injured the mice in one of three ways: by creating nerve damage, inflammation or an incision. After these injuries, both the normal mice and the mice with silent C-LTMRs became hypersensitive to heat. However, unlike normal mice, the engineered mice did not become hypersensitive to mechanical stimulation. This suggests that following injury, C-LTMRs might be recruited into the pain circuitry.