A new study has detailed microscopic brain changes following a concussion, and outlined a probable mechanism for swelling that could lead to better treatments in the future.

For the study, researchers from The Ohio State University induced mild traumatic brain injury on mice brain tissue by delivering blasts of liquid to the tissue with a pipette in a method known as “puffing.” They discovered there was swift subcellular-level swelling along the axons.  Axons are a long threadlike part of a nerve cell that signals to other parts of the brain.

“We think based on our study in an animal model and in the lab that it’s highly likely that when a person has a concussion some of the neurons swell within a few seconds, much more rapidly than we expected,” study author Chen Gu, associate professor of biological chemistry and pharmacology, said in a prepared statement.

Luckily, the swelling is reversible, the researchers found.

“When we stop the mechanical stress, the swelling actually disappears within minutes and the axon can recover,” Gu said. “This is critical, because the axon is where important signals happen – four our sense, motor skills, cognition, emotion and all kinds of neurophysiological functions.”

These findings are likely very relevant to mild traumatic brain injury and correlate with what is observed in the clinic, in that most people make a full recovery over time, Gu noted.

The team also identified that a chain reaction from a stress activated protein called TRPV4 was the likely mechanism behind the swelling. Swelling did not occur when the researchers suppressed TRPV4. This information could be important for better prevention and treatment of concussions.

“It’s like having a highway with a lot of cargo running in both directions.  After the concussion, the highway closes and there’s a major traffic jam,” Gu said. “If the stress to the brain stops, the highway opens back up and the cargo slowly starts to move again.”

Gaining a better understanding of the difference between reversible and irreversible damage could aid the development of new treatment strategies, according to Gu.

The results were published in the Journal of Cell Biology

Contributing Editor/Science Writer