Mild Traumatic Brain Injury Secrets Revealed: Concussions in Humans and Mice

Concussions don't just impact a person immediately after the injury; they also have the potential to affect a person for years afterward. Sports-related concussions have been linked with damage to the brain as a person ages. Now, though, scientists have learned a bit more about mild traumatic brain injuries. It turns out that while the brain may appear to be intact, the brain's protective coverings may feel the brunt of the impact.

In order to learn a bit more about brain injuries, the researchers examined individuals who had recently suffered from a concussion but whose initial scans did not reveal any physical damage to the brain tissue. After administering a dye during MRI scans, the scientists saw it leaking into the meninges, the outer covers of the brain, in 49 percent of 142 patients. Intrigued by this, the scientists then used a newly developed mouse trauma model to better study what was occurring.

"In our mice, there was leakage from blood vessels right underneath the skull bone at the site of injury, similar to the type of effect we saw in almost half of our patients who had mild traumatic brain injury," said Dorian McGavern, one of the researchers, in a news release. "We are using this mouse model to look at meningeal trauma and how that spreads more deeply into the brain over time."

In the end, the scientists found that the intact skull bone was porous enough to allow small molecules to get through to the brain. They showed that smaller molecules reached the brain faster and to a greater extent than larger ones. This revealed that the protective barriers that the brain has may not be concrete.

That's now all they discovered, either. They also found that by applying glutathione, which is an antioxidant normally found in our cells, directly on the skull surface after brain injury reduced the amount of cell death by 67 percent. Applying glutathione about three hours after injury reduced cell death by 51 percent.

The findings could help treat traumatic brain injuries in the future. As mild traumatic brain injuries become more of a public health concern, researchers are looking more closely at what their effects might be on an individual and how best to treat them. These findings show that the inflammatory response in a mild traumatic brain injury model is actually beneficial during the first 9 to 12 hours after injury.

The findings are published in the journal Nature.