Researchers at Dalhousie Medical School and the Brain Repair Centre claim to have found a method that allows them to bypass the nervous system to stimulate muscles. The researchers intends to use light to stimulate the muscles directly to address muscle-wasting and paralysis caused from nerve injuries and neurodegenerative diseases.
Dr. Victor Rafuse, professor in the Department of Medical Neuroscience and director of the Brain Repair Centre, and his collaborator, Dr. Ying Zhang, an assistant professor in the same department, have demonstrated direct muscle stimulation with light. Dalhousie surgery resident and Ph.D. candidate, Dr. Philippe Magown, and masters student, Dr. Basavaraj Shettar, worked with Drs. Rafuse and Zhang on the project. They published their findings in the journal, Nature Communications, on October 13, 2015.
Dr. Rafuse said that they found that just by shining LED light on muscles through the skin for an hour a day can prevent atrophy in completely dennervated muscles. Dr. Rafuse commented, “Others have used light to successfully stimulate nerves, but we are the first to bypass the nerves and go straight to the muscles. This is vital, because the nerve tissue is completely destroyed in many injuries and in diseases like ALS, so you can’t rely on stimulating nerves to activate muscles.”
The researchers inserted a light-activated gene extracted from a single-celled aquatic organism, Chlamydomonas reinhardtii, into a line of mice. When stimulated with a specific wavelength of blue LED light the mice muscles were able to contract.
“Our next step is to develop a means of delivering the light-activated gene directly to the muscles, without altering the genome,” Dr. Rafuse said. “Then we would have a viable therapeutic strategy for human use.”
Dr. Rafuse suggested that the gene could be injected into the hand muscles of a person suffering from a peripheral nerve injury that severed the nervous system’s connection to the hand. “We see the possibility of developing a ‘light glove’ they could wear to prevent atrophy in those muscles and use it to stimulate muscle contractions whenever they want to grasp something.”
The technology could also stimulate the diaphragm of people with ALS who have respiratory problems from their loss of motor neurons and synaptic connections that supply nerves to their muscles used in breathing.