Concussions, even the mildest ones, can leave a long-term impact on neurological functioning. A latest study by National Institutes of Health shows while the brain might remain intact after a mild trauma, the protective covering around the organ is severely damaged.
Dorian McGavern, Ph.D., scientist at the National Institute of Neurological Disorders and Stroke (NINDS) and colleagues used mouse models to understand how concussion affects brain. They found that certain cells in the brain begin an immune response to prevent further damage. Researchers believe that humans might have a similar mechanism to cope with a head injury.
"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. We are using this mouse model to look at meningeal trauma and how that spreads more deeply into the brain over time," said Dr. McGavern.
In the present study, researchers filmed the brain's defence mechanism after the injury.
In the first stage, cells in meninges and at the glial limitans begin to die. It takes about nine to 12 hours after an injury for the underlying brain cells to stop functioning.
Harmful molecules enter the brain when the glial limitans breaks-down. Researchers found that microglia (a kind of immune cells) reach the brain surface to prevent these moleciules from getting into the brain.
The study team also found that certain molecules could get past the hard skull bone. According to researchers, applying glutathione (an antioxidant) on the skull after a head injury could prevent cell death by 67 percent whereas applying the antioxidant after 3 hours reduced cells death by 51 percent.
"This idea that we have a time window within which to work, potentially up to three hours, is exciting and may be clinically important," said Dr. McGavern in a news release.
Glutathione decreases the levels of reactive oxygen species (ROS) molecules. In the present study, ROS were seen accumulating at the injury site and beginning the mechanism that leads to cell death. The antioxidant was able to disrupt this mechanism.
Mild injuries to the brain or concussion during sports can damage the brain that can take a while to recover. People who have had repeated concussions have been known to have severe brain damage.