Now, recent research published in the journal Science suggests that astronauts may be subject to similar neurological impairments if they are subject to long-term exposure to cosmic rays or other space-derived radiation. The researchers have shown long-term exposure to these space rays may cause cognitive impairments similar to dementia in astronauts who plan to travel to Mars.
To conduct the experiments leading to this conclusion, researchers at the NASA Space Radiation Laboratory exposed mice to ionized oxygen and titanium, elements found in cosmic rays, thus mimicking the galactic cosmic rays in space. For easy visualization and imaging, the mice were genetically modified to express green fluorescent protein (GFP) in their neurons. Six weeks after their exposure, researchers at UC Irvine studied the mouse brains and found distinct changes in them. This included notable inflammation which was enough to disrupt communication between the neurons.
As described in an article about the research published in Popular Science, “the particles acted like tiny bullets, flying into the brain and breaking off neuronal structures known as dendrites.” A similar process of losing neuronal integrity occurs in neurodegenerative diseases such as Alzheimer’s disease.
To determine if these structural changes were associated with behavioral changes in the mice, the exposed mice were also subject to another set of experiments. These experiments found the mice exposed to the space-like radiation exhibited less curiosity than other mice while also being more confused in the tasks they were performing. In other words, exposure to ionized particles mimicked the symptoms associated with both cognitive decline and “chemo brain.” Altogether, this recent research serves as a cautionary warning for NASA and the other companies that are intensively planning a manned mission to Mars. As Charles Limoli, professor of radiation oncology at UC Irvine’s school of medicine said, “This is not positive news for astronaut [who would be] deployed on a two- to three-year round trip to Mars.”
(Photo courtesy of Cyril Rana)