California Scientists Make Paralyzed Rats Walk Again

September 21, 2009 8:17 a.m. EST

Los Angeles, CA (AHN) - Scientists at University of California, Los Angeles used combination of drugs, regular exercise and electrical stimulation to make paralyzed rats walk and run again.

The researchers said in a statement that their findings show that the regeneration of severed nerve fibers is not required to make paraplegic rats learn to walk again, and the same may hold true for humans suffering from spinal cord injuries.

Lead researcher Reggie Edgerton, a professor of neurobiology and physiological sciences at the David Geffen School of Medicine at UCLA, said in a statement that the spinal cord contains nerve circuits that can generate rhythmic activity without input from the brain, which can move the hind leg in a way that resembles walking.

Previous studies similarly resulted in stimulation of the same circuitry, but the latest UCLA study was the first where the subjects were able to walk and run while supporting their full body weight.

The rats, which had complete spinal injuries and no voluntary movement in their hind legs, were give drugs that act on the neurotransmitter serotonin. They also received low levels of electrical currents to the spinal cord point of injury. After several weeks of training, the rates were able to support their full body weight while walking on a treadmill.

But the rats still weren't able to walk on their own because the injury interrupted the brain's connection to the spinal cord-based circuitry that allows movement of the legs. Prosthetic devices that stimulate movement may help solve this problem in the future, the researchers said.

The study is published in the online edition of the journal Nature Neuroscience.