Spinal cord injuries result in paralysis when the nerve fibers that carry information to and from the brain are damaged or severed. Much of the focus of research into spinal cord injuries has been exploring ways of regenerating those nerve fibers and connections, which has so far met with limited success in people.
In the new study, rats were treated with a combination of drugs, electrical stimulation of the spinal cord and locomotor training, a rehabilitation technique. The combined treatment enabled the rats to walk with a near-normal gait on a treadmill, without the muscles receiving signals from the brain.
"The study demonstrates that the lower spinal cord has circuitry that is sufficient to support virtually normal, weight-bearing locomotion," said senior study author V. Reggie Edgerton, a professor of physiological sciences and neurobiology at the University of California, Los Angeles.
The study appears in the Sept. 20 online edition of Nature Neuroscience.
Previous research has been able to coax a stepping motion using one or two of those techniques, said Susan Howley, executive vice president of research for the Christopher & Dana Reeve Foundation, which provided some funding for the current research. But this is the first study to achieve actual weight-bearing walking, as opposed to the motions of walking.
"The thing that's very exciting about this is that for the first time they actually showed they can get these rats, with no input from the brain, to step near normally," Howley said. "On the treadmill, they were able to bear weight and step virtually as well as they had been prior to the injury. That's a remarkable achievement."
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