Light may be effective treatment for chronic pain, study says

Researchers reduced pain in mice using optogenetics, and think it may be possible to do the same in people.

By Stephen Feller

MONTREAL, April 20 (UPI) -- With opioid dependency and misuse issues continuing to grow nationwide, researchers are looking to non-opioid options for pain control -- including light.

Researchers at McGill University in Canada reduced pain in mice by shining light on the affected area using a technique called optogenetics, according to a study published in the journal eNeuro.


Optogenetics uses light to control neurons, in the case of pain by turning them off when light shines on them. Researchers think the non-invasive specificity of using light, as well as eliminating concerns about opioid drug dependency for people using the drugs over long periods of time, could be a better method for controlling chronic pain.

While the technology is not at a point that researchers think it is applicable to humans, they envision methods by which it could be used.

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"Chronic pain is an increasingly big problem clinically and for many years we've relied only on opiates," Philippe Séguéla, a researcher at the Montreal Neurological Institute and Hospital, said in a press release. "It's hard to treat because of tolerance, making it necessary to increase dosages, which leads to serious side effects. Optogenetic therapy could be a highly effective way to relieve chronic pain while avoiding the side effects of traditional pain medication."


For the study, researchers bred mice with a light-sensitive trait making peripheral neurons, called Nav 1.8+ nociceptors, release proteins that react to light. Shining yellow light on these neurons shuts them off, decreasing sensitivity to touch and heat.

The researchers found shining light decreased pain, suggesting an on-demand system of pain management could be possible, without the potential for drug dependency.

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Although the researchers said it may be possible to use a harmless virus to change neurons in the body and make them sensitive to light, however further technological and neuroscientific research is necessary before optogenetics can be tested in humans, they said.

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