Researchers develop new hope for victims of paralysis

Scientists at the Karolinska Institute, Sweden, have created genetically-modified mice with neurons that have been designed to be 'activated' by a blue light, initiating motor activities that control the action of walking.

The research could be a breakthrough for humans who have suffered spinal cord damage, which often robs them of the ability to walk. The genetically modified mice were engineered with Channelrhodopsin2 (ChR2), a light-sensitive protein usually found in algae. When exposed to light, ChR2 activates the cell in which it is being expressed; the researchers realised that, by housing the protein in the excitatory neurons located in the spinal cord, ChR2 could be used to trigger activity in the neurons.

In the mice that contained the ChR2 protein, the researchers inserted the protein into Vglut2 nerve cells – Vglut2 being a transporter found in excitatory neurons in the brain stem and spinal cord. In cells isolated from this 'Vglut2-ChR2' mouse, it was observed that locomotive action was initiated by shining a blue light on the neurons. With the discovery that excitatory cells in the brain stem can provide a sufficient activity signal to the spinal neurons involved in walking, the discovery could potentially be applied to human cells.

"This new mouse model will impact the way in which future studies examining the organization of neurons involved in walking are performed. We hope that our findings can provide insight that eventually will contribute to treatments for spinal cord injured patients", says Professor Ole Kiehn, who lead the study.

For more information on the study, contact Katarina Sternudd at katarina.sternudd@ki.se

Published: Monday, 25th January 2010 by Tom Freeman

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