Symptoms of a concussion after the moment of impact or trauma may be obvious (such as passing out), fuzzy (feeling slow or having difficulty remembering), or not be present at all. But what about damage that can't be seen? Stanford undergraduate Theo Roth, a senior majoring in biology, is first author of a study with researchers from the National Institutes of Health that observes the brain's response to a concussion at the cellular level.
Using an intracranial microscope, the researchers examined the effects of traumatic brain injury in mice for a few hours immediately after a head injury. A Stanford Report article today explains the cellular mechanics noted in the study:
The brain's first line of defense is called the meninges, a thin layer of tissue that wraps the brain and creates a nearly impermeable barrier to harmful molecules. At the direct site of the injury, however, Roth found that the meninges can become damaged, tearing blood vessels and causing hemorrhaging. As cells in the meninges and other nearby tissues die, their toxic innards – in particular, molecules called reactive oxygen species (ROS) – can leak through the meninges onto healthy brain cells.
The brain tries to plug the holes in the meninges, Roth said, by quickly mobilizing special cells called microglia toward the site of the injury, a reaction that had never been seen in living brains before this study. The patch isn't perfect, however, and some ROS and other potentially toxic molecules still leak through to the brain cells. Within nine to 12 hours after the initial injury, brain cells begin to die.
The researchers also looked for ways to prevent the damage they had observed in mice, finding that the natural antioxidant glutathione could neutralize ROS molecules and minimize damage if applied soon after injury. And, the article reports, these findings could have implications for treating concussions in humans.
The study (subscription or purchase required) was published online in Nature.
Previously: Now that’s using your head: Bike-helmet monitor alerts emergency contacts after a crash, Traumatic brain injuries: An issue both on the battlefield and the playing field, Kids and concussions: What to keep in mind and Measuring vs. reporting concussions in cheerleading
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