By Staff

Early research using green light-emitting diodes (LED) is showing some promise in rats as a novel, non-pharmacological approach to managing pain. And researchers are excited enough to start a human clinical trial for people with fibromyalgia.

Researchers at the University of Arizona had results of their study published in the February 2017 issue of the journal Pain.

In the study, rats with neuropathic pain showed more tolerance for thermal and tactile stimulus when bathed in green LED compared to rats with neuropathic pain that were not exposed to the greed LED.

The effects of the green LED lasted for four days after the rats’ last exposure to the light. There were no side effects from the green LED therapy, and there was no tolerance to the therapy.

“Chronic pain is a serious issue afflicting millions of people of all ages,” says Mohab Ibrahim, UA assistant professor of Anesthesiology and Pharmacology and lead author of the study. “Pain physicians are trained to manage chronic pain in several ways including medication and interventional procedures in a multimodal approach. Opioids, while having many benefits for managing pain, come with serious side effects. We need safer, effective and affordable approaches, used in conjunction with our current tools, to manage chronic pain. While the results of the green LED are still preliminary, it holds significant promise to manage some types of chronic pain.”

To receive the green LED exposure, one group of rats were placed in clear plastic containers that were affixed with green LED strips, allowing them to be bathed in green light. Another group of rats was exposed to room light and fitted with contact lenses that allowed the green spectrum wavelength to pass through. Both groups benefitted from the green LED exposure. However, another group of rats was fitted with opaque contact lenses, which blocked the green light from entering their visual system. These rats did not benefit from the green LED exposure.

“While the pain-relieving qualities of green LED are clear, exactly how it works remains a puzzle,” says Rajesh Khanna, UA associate professor of Pharmacology and senior author of the study. “Early studies show that green light is increasing the levels of circulating endogenous opioids, which may explain the pain-relieving effects. Whether this will be observed in humans is not yet known and needs further work.”

researchers are now conducting a small, randomized, double-blind clinical trial to study the effects of green LED light on people with fibromyalgia, a common source of chronic pain. Participants are provided with a green LED light strip to use in a darkened room for one to two hours nightly for 10 weeks.

Robin Tricoles from University of Arizona News writes,

So far, the results of the trial look promising. Two participants even refused to return the green LED light because their pain was markedly diminished, and one participant wrote to Ibrahim telling him how positive the experience was — and asked for the light back. Ibrahim obliged.

Also of note, the therapy works equally well in males and females, Khanna says. “There’s no lesser efficacy in females, and that’s exciting because some medications will have some pain relief and that may be further stratified based on gender,” he says. The hope is that green LED light therapy will alleviate the participants’ pain when used alone or in combination with other treatments including physical therapy or low-dose analgesics.

Todd Vanderah, professor and chair of pharmacology and co-author of the study, says that novel non-pharmacological methods are desperately needed to help the millions of individuals suffering from chronic pain. The initial results, hinting of green LED altering the levels of endogenous substances that may inhibit pain and possibly decreasing inflammation of the nervous system, are a great breakthrough, Vanderah says. Such therapy is inexpensive and could easily be used worldwide.

At the very least, the researchers are hoping that green LED may be used by itself or in combination with other treatments for pain, Ibrahim says.

“Chronic pain is a serious issue afflicting millions of people of all ages,” he says. “Pain physicians are trained to manage chronic pain in several ways, including medication and interventional procedures in a multimodal approach. Opioids, while having many benefits for managing pain, come with serious side effects.

“We need safer, effective and affordable approaches, used in conjunction with our current tools, to manage chronic pain. While the results of the green LED are still preliminary, it holds significant promise to manage some types of chronic pain.”

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