The discovery made ba a UCLA team could lead to new therapies for the estimated 250,000 Americans who suffer from traumatic spinal cord injuries. An additional 10,000 cases occur each year, according to the Christopher and Dana Reeve Foundation, which helped fund the UCLA study.
“Imagine the long nerve fibers that run between the cells in the brain and lower spinal cord as major freeways,” explained Dr. Michael Sofroniew, lead author and professor of neurobiology at the David Geffen School of Medicine at UCLA. “When there’s a traffic accident on the freeway, what do drivers do? They take shorter surface streets. These detours aren’t as fast or direct, but still allow drivers to reach their destination.
“We saw something similar in our research,” he added. “When spinal cord damage blocked direct signals from the brain, under certain conditions the messages were able to make detours around the injury. The message would follow a series of shorter connections to deliver the brain’s command to move the legs.”
Using a mouse model, Sofroniew and his colleagues blocked half of the long nerve fibers in different places and at different times on each side of the spinal cord. They left untouched the spinal cord’s center, which contains a connected series of shorter nerve pathways. The latter convey information over short distances up and down the spinal cord.
“We were excited to see that most of the mice regained the ability to control their legs within eight weeks,” said Sofroniew. “They walked more slowly and less confidently than before their injury, but still recovered mobility.”
When the researchers blocked the short nerve pathways in the center of the spinal cord, the regained function disappeared, returning the animals’ paralysis. This step confirmed that the nervous system had rerouted messages from the brain to the spinal cord via the shorter pathways, and that these nerve cells were critical to the animal’s recovery.
MEDICA.de; Source: University of California - Los Angeles