While male-dominated sports like football and boxing receive most of the attention when it comes to concussions, a growing body of evidence suggests that women actually face significantly more risk for brain injuries. Recent findings would indicate that females are at least 50% more likely to experience brain injuries compared to males.
As these disparities are becoming largely accepted by the medical field, researchers have gone in search of reasons for why women are so much more at risk. Now, according to a report published in the journal Experimental Neurology, a team of researchers from the University of Pennsylvania believes they may have found the answer.
The team, led by Dr. Douglas H. Smith from the Penn Center for Brain Injury and Repair, says they believe gender differences in the nerve fibers of the brain’s “electric grid” may contribute to women’s higher concussion risk.
Based on studies of in vitro rat and human cells, examined using transmission electron microscopy, women appear to have leaner and more fragile nerve fibers compared to men. Their axons – the parts of neurons that help transmit information between cells – have fewer and more breakable microtubules. These “train tracks” are essential for intracellular transport of molecules.
“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.”
When a concussion occurs, the impact stretches axons to the point that it frequently ruptures the microtubules. The team says this produces the dizziness, confusion, headache, and even the loss of consciousness from a concussion.
Twenty-four hours after the researchers inflicted trauma to the cells, the researchers found that female axons showed more swelling and loss of calcium-signaling function compared to male axons. The buildup of proteins could potentially trigger a destructive enzyme that further degrades axons and damages nerve fibers.
These anatomical differences between the genders may be the key to understanding the greater concussion risks in women, according to Smith and colleagues.
“You can imagine that if something goes wrong with that transport system, the cargos get dumped out and start to pile up and that will create a huge problem,” Smith said.
The findings are just the start of the exploration into the complex mechanisms that underlie brain injuries in both sexes, but the team believes their work will help progress further research. Their hope is to eventually create treatment options specifically designed to help women following concussions.