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Science: New Rehabilitation Method for Paralyzed Rats Restores Ability to Walk
Swiss Federal Institute of Technology researcher Gregoire Courtine discusses his team’s study on neurorehabilitation in the rat spinal cord
[Video and images courtesy of EPFL]
Scientists have developed a rehabilitation method that enables paralyzed rats with severed spinal cords to walk again. The findings raise the possibility that a similar method might someday be effective in humans with severe spinal cord injuries.
Neuronal damage to a severed spinal cord is generally considered too great for repair, even though the nervous system does have a remarkable capacity to forge new connections around an injury.
In research that challenges this view, Rubia van den Brand of the University of Zurich and the Swiss Federal Institute of Technology and colleagues studied rats with spinal cord injuries similar to those causing lower-body paralysis in humans. The results appear in the 1 June issue of Science.
The researchers excited the spinal cord neurons that were dormant after the injury, using both electrical stimulation and injections of neuron-activating chemicals. This step reactivated the neurons controlling the rats’ hind limbs and primed them to make new connections. The researchers then outfitted the rats with special vests attached to a robotic system that supported the animals, holding them up on their hind legs and enabling them to move forward.
After several weeks of neurorehabilitation, previously paralyzed rats are voluntarily initiating a walking gait, and soon sprinting, climbing up stairs and avoiding obstacles.
Over a nine-week period, one group of rats learned to walk across solid ground in order to reach a treat. These animals even managed to sprint up stairs or step over a low obstacle to get to their reward. The rats moved voluntarily, bearing their full weight on their hind legs.
In contrast, other rats were trained on a treadmill. These rats also moved their legs automatically, as the treadmill moved beneath their feet. But without the active decision-making that the first group of animals engaged in, the treadmill-trained rats did not manage to walk voluntarily on solid ground.
The successful rehab procedure, the Science authors say, appears to extensively remodel neuronal circuitry all way from the spinal cord up through the brain.
31 May 2012