A bunch of paralyzed rats at the Swiss Federal Institute of Technology (EPFL) in Lausanne, Switzerland are happily walking, running, and scampering up stairs again, thanks to a team of EPFL scientists.
These rats, which had paralyzing lesions interfering with their spinal cords, similar to injuries that cause lower-body paralysis in humans, were able to voluntarily move their legs in a walking gait after only a couple weeks of neuro-rehabilitation that involved two steps to “awaken” a dormant spinal column. According to an announcement from the Swiss Federal Institute of Technology:
[Grégoire] Courtine [lead author of the study] and his team injected a chemical solution of monoamine agonists into the rats. These chemicals trigger cell responses by binding to specific dopamine, adrenaline, and serotonin receptors located on the spinal neurons. This cocktail replaces neurotransmitters released by brainstem pathways in healthy subjects and acts to excite neurons and ready them to coordinate lower body movement when the time is right.
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, called the epidural space. “This localized epidural stimulation sends continuous electrical signals through nerve fibers to the chemically excited neurons that control leg movement. All that is left was to initiate that movement,” explains Rubia van den Brand, contributing author to the study.
Amazingly, after training the rats by placing them in a mechanical harness to assist with balance, and encouraging them with a chocolate reward at the end of the walking platform, Courtine and his team actually measured a fourfold increase in nerve fibers throughout the brain and spine that bypass the injured section, showing impressive neuroplasticity of the nervous system even after a severe spinal cord injury. (In contrast, an earlier study involving a treadmill that facilitated forward movement showed no regrowth of nerve fibers.)
Of course, it’s not guaranteed that similar methods will work for humans. However, observing the amazing plasticity of the rats’ nervous systems as a result of these techniques makes scientists optimistic about new methods for treating paralysis.
Take a look at the video below of lead author Grégoire Courtine explaining the technique and showing off one of the paralyzed rats shuffling down a walking platform:
More info from EPFL: Walking Again After Spinal Cord Injury…
Journal abstract in Science: Restoring Voluntary Control of Locomotion after Paralyzing Spinal Cord Injury