Space & Innovation

Rodents in Space Will Show How Genes Are Affected by Microgravity

Space is tough on an astronaut's bones, muscles, blood flow and much more.

Getty Images: Eugen Wais/EyeEm

Flying in space can be a bit like growing old, because without exercise and proper nutrition astronauts on weeks- or months-long missions would come back to Earth with difficulties staying balanced, with weaker bones and muscles, and with other health problems that are usually confined to seniors or those with disease.

To help better understand these effects, a new investigation on the International Space Station (ISS) will study aging and how the age of mice living in microgravity affects the progression of symptoms that mimic some human diseases. Rodent research in space has been performed many times on the space shuttle and more recently on the ISS to better understand the effects of microgravity on astronaut health. The mice in this experiment will stay in space for over 30 days to provide a better idea how spaceflight effects on their health can inform us about human health on Earth.

This is the ninth Rodent Research mission launched to the ISS since 2014. Each mission has specific science goals,and studied different responses of the mice to spaceflight or therapeutic drugs (or sometimes, both at the same time). While it is possible to make some comparisons between spaceflights, it can be a challenge when mice of different genetic types or genetic backgrounds fly on different missions.

This situation makes it difficult to predict how the genetic background of a particular type of mouse may influence the effects of microgravity in other genetic backgrounds of mice. (Similar things happens with humans; certain genes predispose people to certain types of diseases, such as cancer.) So Rodent Research-8 aims to examine genetic influences more closely.

"This mission is different from previous missions as it is the first reference mission where young and old mice of the same genetic strain are flown together during the same mission," said co-investigator Gretchen Kusek, the associate director of scientific services at private company Taconic Biosciences, in an e-mail to Seeker.

"Genetic background dictates the underling molecular mechanisms contributing to the aging process, so utilizing genetically identical mice removes a variable when analyzing the data. Furthermore, this mission will provide space-flown samples to researchers that have agreed to share their data and results in an online database that is open to the public."

The researchers are from several institutions and will run their own investigations to test how spaceflight and the aging process affect certain organ systems in mammals, especially those effects that might be comparable to human diseases such as osteoporosis, muscle wasting and immune dysfunction, said principal investigator Michael Roberts, deputy chief scientist at the U.S. National Laboratory (which is also sponsoring the investigation).

"These research questions will be addressed by observing the activity levels of the younger and older mice and different measures of activity and function in their genes and major organ systems," he said in an e-mail to Seeker.

While mice and rats are not human subjects, Roberts says they are good models for probing the effects of spaceflight on mammalian systems – such as cardiovascular or reproductive systems – that humans share. Rodents are also prone to many human-type diseases, including diabetes, osteoporosis and even cancer. Another advantage of rodents is they have shorter lifespans and breed more quickly than humans, allowing researchers to quickly see the effects of aging in a single generation exposed to microgravity for a few weeks.

"Our mission at the ISS National Lab is to enable research in space that benefits Earth. The NASA Human Research Program has the mission to identify and mitigate risks to astronauts.  This experiment directly addresses both missions by seeking to improve our understanding of the effects of spaceflight on human physiology using an animal model, to reveal how these effects may be exacerbated or attenuated by age and how faithfully these molecular and physiological changes mimic disease," Roberts said.

"The data collected will be used to inform those of us on Earth about new, early-stage biomarkers of disease. For those working in space, these biomarkers will be used to inform physicians and engineers about effectiveness of current and planned countermeasures to combat physiological changes associated with extended spaceflight," he added.

Waiting for results will still take a while, because analyses on the data take at least a year or more to perform after the mice and associated biospecimens (such as blood samples) return to Earth. It's not as though mice can easily catch a ride home; they have to wait for a SpaceX Dragon spacecraft to come to the station, which only happens a few times a year at best.

Future rodent missions may focus on the effects of spaceflight on males and females, and how their sex alters disease onset and progression, Roberts said.

You can read more about the experiment at this NASA web page.