Rats with spinal cord injuries are walking

Rats with spinal cord injuries and severe paralysis were able to walk after their dormant spinal column was woken up, Swiss researchers said. Lead author Gregoire Courtine of the University of Zurich said it was unclear whether similar rehabilitation techniques could work for humans, but the observed nerve growth hinted at new methods for treating paralysis. "After a couple of weeks of neurorehabilitation with a combination of a robotic harness and electrical-chemical stimulation, our rats are not only voluntarily initiating a walking gait, but they are soon sprinting, climbing up stairs and avoiding obstacles when stimulated," Courtine, chairman of the International Paraplegic Foundation, said in a statement. The brain and spinal cord can adapt and recover from moderate injury, a quality known as neuroplasticity, but until now, the spinal cord expressed so little plasticity after severe injury that recovery was impossible. Courtine said his findings prove, under certain conditions, plasticity and recovery can take place in these severe cases after the spinal cord was injected a chemical solution of monoamine agonists. These chemicals trigger cell responses by binding to specific dopamine, adrenaline and serotonin receptors located on the spinal neurons, Courtine said. Five to 10 minutes after the injection, the scientists electrically stimulated the spinal cord with electrodes implanted in the outermost layer of the spinal canal, which sent continuous electrical signals through nerve fibers to the chemically excited neurons that control leg movement, the researchers said. The findings are scheduled to be published in the June 1 issue of Science.