Scientists Regenerate Axons in Rats Months after Spinal Cord Injury

In the October 29 issue of the Cell Press Journal Neuron, a team of researchers from the University of California, San Diego School of Medicine report that they achieved regeneration of central nervous system axons in rats even when treatment was delayed for more than a year after the spinal cord injury.

Lead author Mark Tuszynski, director of the Center for Neural Repair at UC San Diego, said, “The good news is that when axons have been cut due to spinal cord injury, they can be coaxed to regenerate if a combination of treatments is applied. The chronically injured axon is not dead.”

This is the first study to show that regeneration is possible even long after the original injury. The researchers demonstrated successful regeneration of spinal cord axons into and beyond a cervical injury site. Treatment started at time periods ranging from six weeks to 15 months after the time of the injury in the adult rats.

Many factors make regeneration of nerves difficult. Such factors include the formation of scar tissue around the injury, a partial deficiency in the growth capacity of adult neurons, the presence of growth inhibitors, and often extensive inflammation around the injury site. Furthermore, injured neurons often lose the ability to express genes that promote regeneration. Even in the ideal laboratory environment, axonal regeneration has been difficult to achieve. The regeneration of axons after spinal cord injury requires a combination of therapies including: a cellular bridge in the injury site; administration of central nervous system growth factor to guide axonal regeneration; and some sort of stimulus to activate the genes for regeneration within the injured neurons. By combining these techniques, the researchers were able to achieve axonal regeneration beyond the injury site in the rats, even when treatment did not start until 15 months after the injury. The rats did not receive all elements of the combination treatment did not experience axonal regrowth.

The research team also discovered that broad sets of genes which support regeneration can be reactivated long after a spinal cord injury. In other words, even a chronically injured cell can still be primed to grow.

"Our findings indicate that there is potential for promoting repair of the injured spinal cord even in chronic stages of injury. While the regenerating axons grow for relatively short distances, even this degree of growth could be useful. For example, restoration of nerve function even one level below an injury in the neck might improve movement of a wrist or hand, providing greater quality of life or independence," Tuszynski said.

Nearly 250,000 people in the United States are living in the chronic stages of spinal cord injury, and 10,000 new spinal cord injuries occur each year.

This is an exciting time for spinal cord injury research. I am hopeful that some significant progress will be made in treatments within the next decade.

If you have suffered a spinal cord injury due to the negligence or recklessness of an individual, business or organization, you may be entitled to monetary compensation. Contact a Georgia spine injury lawyer to ask about your legal rights. Call 404-531-9700 to schedule a free consultation.