Paralysed rats have been
able to walk again after their spinal cords were bathed in chemicals and
zapped with electricity, scientists have shown.
An injury to the spinal cord stops the brain controlling the
body.
Experts said it was an "exceptional study" and that restoring
function after paralysis "can no longer be dismissed as a pipedream".
In 2011, a man from Oregon in the US
was able to stand up again while his spinal
cord was stimulated with electricity. Rob Summers had been paralysed
from the chest down after being hit by a car.
Now researchers at the Swiss Federal Institute of Technology
(EPFL) say they have restored far more movement in rats which became
able to run and climb stairs.
'Reawakening'
End Quote
Dr Bryce Vissel
Garvan Institute of Medical Research
in Sydney
The spinal cord of the rats was
cut in two places. It meant messages could not travel from the brain to
the legs, but the spinal cord was still in one piece.
The researchers then tried to repair the damage. In an
advance from the Rob Summers study, the spinal cord was first injected
with chemicals to stimulate the nerves in the spine. The base of the
spinal cord was then electrically stimulated as well. The scientists say
they were reawakening the "spinal brain".
However, this was not sufficient to restore movement. The
rats were supported in a robotic harness and were shown a treat which
they needed to "learn" to walk towards.
The lead researcher, Prof Gregoire Courtine, said: "Over time
the animal regains the capacity to perform one, two steps, then a long
run and eventually we gain the capacity to sprint over ground, climb
stairs and even pass obstacles."
He told the BBC: "It is completely unexpected to see this
recovery, they walk and climb stairs voluntarily."
The scientists showed that new nerves were forming across the
injury and there were also changes in the brain.
This is not, however, a cure for spinal cord injuries in
people.
Rob Summers: ''The moment I stood up, I was in
disbelief''
Prof Reggie Edgerton, from the
University of California Los Angeles, was part of the team which helped
Rob Summers stand again.
He told the BBC the study was "important" and that it was
becoming clear that engaging the brain was the key. "You've got to make
the rat want to step, it demonstrates the importance of training and
rehabilitation," he said.
Both procedures only work while the spinal cord is still
being stimulated, even though new nerves have bridged the injury.
Why this is the case is still
unknown. Prof Edgerton speculated that "we are activating the spinal
cord to a critical level" close to the level which would trigger
movement, and a small signal from "the brain pushes it over" leading to
movement.
Dr Bryce Vissel, from the Garvan Institute of Medical
Research in Sydney, said he was "excited" by the research.
He said: "The major advance of this new study is to show that
it is possible to stimulate almost complete functional recovery in rats
with profound injury, using a combination of therapeutic drugs injected
into the spinal cord, electrical stimulation of the spinal cord and
initial assistance to walk.
"We are on the edge of a truly profound advance in modern
medicine: the prospect of repairing the spinal cord after injury."
Dr Mark Bacon, the director of research at the charity Spinal
Research, said: "This is a robust demonstration that medical research
is moving in the right direction and restoring function after paralysis
can no longer be dismissed as a pipedream.
"For all its complexity, the important message here may be
that our standard approach to rehab may not be making the most of the
potential to restore function if we don't provide appropriate
'rewarding' feedback to every part of the nervous system, including the
brain."
However he warned that "real world" injuries might be more
complicated, with less tissue for new nerves to grow through.
source : http://www.bbc.co.uk/news/health-18257077
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