Imaging of rodent brains repairing themselves could improve concussion, mTBI treatment
A real-time look at how mice’s immune systems repair their brain lining, or meninges, after concussion or mild traumatic brain injury (mTBI) is providing insight into how the human brain heals itself in similar situations, the National Institutes of Health (NIH) reported this week.
The research, led by NIH scientists and published this month in Nature Immunology, revealed that not only does the immune system jump into action after brain injuries in mice—deploying a handful of distinct monocytes at stages throughout the healing process—but why a second blow to the head shortly after the first could be a far more devastating injury.
“The lining of the brain, with help from the immune system, has a remarkable ability to put itself back together again after injury,” senior author Dorian McGavern, PhD, said in an NIH release. “As we learn more about all the cells involved in the repair process, we may be able to identify potential targets for therapy that lead to better outcomes for patients.”
McGavern and his team recorded mice’s immune system reactions to meninges damage for up to one week after the initial injury, noting where monocytes centralized themselves during the process. The group used advanced imaging to capture any progress.
The researchers found that within the first day of a head injury, inflammatory monocytes flocked to the mice’s damaged sites and started to clear away dead cells. A few days later, a different blood monocyte entered the scene and worked around the lesion edge to help rebuild damaged blood vessels.
“Following a head injury, the meninges call in a clean-up crew, followed by a separate repair crew, to help fix damaged blood vessels,” McGavern said.
He said that if re-injury occurred within a day of the first traumatic brain injury, the healing process seemed to halt, never fully taking course. If a second blow to the head came three days after the first hit, though, the meninges seemed able to heal itself completely.
McGavern said that since around half of adult patients who present with mild traumatic brain injury show evidence of blood vessel damage to the meninges, these findings could be important for real-world, clinical applications.
“The timing of a second head injury may determine whether the meninges can be repaired,” he said. “We have shown on a cellular level that two or more head injuries within a very short amount of time can have really dire consequences for the brain lining and its ability to repair.”
After graduating from Indiana University-Bloomington with a bachelor’s in journalism, Anicka joined TriMed’s Chicago team in 2017 covering cardiology. Close to her heart is long-form journalism, Pilot G-2 pens, dark chocolate and her dog Harper Lee.