A new study offers a possible reason why women are more likely than men to have a sports-related concussion, and often take longer to recover.
Researchers at Penn Medicine found that women have smaller, more breakable nerve fibres in the brain compared to men, which may make them more susceptible to concussions.
The team — led by Dr Douglas H. Smith, director of the Penn Center for Brain Injury and Repair and the Robert A. Groff Professor of Neurosurgery at the Perelman School of Medicine at the University of Pennsylvania — conducted a series of laboratory tests using rat and human neuronal cells. The results showed that female axons (nerve fibres) were smaller and had fewer microtubules — “train tracks” that transport molecules up and down the axons — which were more likely to break after applying the same amount of force from a simulated traumatic brain injury.
That breaking is what researchers believe may lead to symptoms associated with concussions, such as dizziness or loss of consciousness, Penn Medicine explained. This susceptibility may also help explain why female athletes have an increased risk of concussions and worse outcomes than male athletes.
“The paper shows us that there is a fundamental, anatomical difference between male and female axons,” Smith said. “In the male axon, there are a great number of microtubules, which make the entire structure stronger, whereas in female axons, it’s more of a leaner type of architecture, so it’s not as strong.”
As a result, axons in female brains may be more susceptible to damage than axons in male brains.
The findings also highlight potential treatment options to study, including microtubule-stabilising drugs that would help reduce microtubule breakdown following brain injury.