Researchers at the University of Arizona in the US are exploring a non-pharmacological method for treating chronic pain with green light-emitting diodes (LED).
The team from Tucson, Arizona (US) bathed rats with neuropathic pain in green LED light, which made the subjects more tolerant to thermal and tactile stimulus than the rats that did not receive the light treatment.
According to the scientists, more than 100 million people suffer from chronic pain in the US alone. “The current available medications are not effective enough or they come with significant side effects,” says Mohab Ibrahim, lead author of the study and assistant professor of anesthesiology and pharmacology at the University of Arizona. The researcher adds that despite the many tools and interventions pain physicians use to manage chronic pain, some types of pain are very hard to treat, such as fibromyalgia or migraines. “We have noticed that light can have some biological functions,” he notes. “For example, bright light is used to treat depression.” What motivated the professor to experiment with light generated by green LEDs? “I personally noticed that green light relieves my headache. So I wanted to investigate the effects of green light on pain modulation.” In the lab, the professor found that green LED light has indeed pain-relieving effects on rats.
Ibrahim is using the existing technology of green LEDs in an entirely new way: to manage chronic pain through the visual system. “We show that green LEDs have strong potential in medical applications, especially in the field of pain management,” he confirms.
Advantages of the new approach to treating chronic pain
Chronic pain is inherently long-lasting, and most available pain medications come with significant side effects and can get very expensive over time. Furthermore, the researcher says while interventional procedures employed by pain physicians can significantly reduce and control pain, they are not always successful and still come with some degree of risks. “Green LED therapy, on the other hand, is far safer than most medications and procedures,” Ibrahim stresses, adding that this form of treatment is not addictive, widely available and relatively inexpensive compared with most medications or medical devices.
Green LED light therapy for humans
In the study, the University of Arizona team has bathed rats in green LED light, but the technology has already been translated to human trials — although these are just beginning, the researchers note. “We currently have a small ongoing clinical trial for patients with fibromyalgia and chronic headaches,” says Ibrahim. “While this is still very early in the process, the preliminary data is encouraging and shows that green LED exposure for several hours a day [leads to] a clear reduction on pain associated with these conditions.”
Impact on future of light-based medical therapy
The professor points out that light-based therapy is already well stablished in medicine. He says bright light has been used for many years to treat some types of serious depression, and that others have shown that certain wavelengths of light can accelerate wound healing. “Our research clearly demonstrates that different spectrums of light can also have different biological responses,” says Ibrahim. “I think, with every new application of light therapy in medicine, the door to fully investigate the potential for light as a therapy for many medical conditions is opening up more and more and is becoming more accepted in mainstream medicine.”
Next step in this research endeavor
Ibrahim says he and his colleagues have “many exciting plans” for the future investigating the mechanism of green LED therapy. “While we see a clear effect on animals and people, we still do not have a full understanding as to how it works,” the professor says, adding that they have applied for federal funding to continue the research in this “exciting and safe field of medicine.” Adds fellow researcher Dr Rajesh Khanna, associate professor in the Departments of Pharmacology, Anesthesiology and Neuroscience at the University of Arizona: “Another advantage of the green LED therapy could be its potential for lowering the need of other medications. In other words, patients may need less opiates or medications like Gabapentin/Lyrica to manage their pain; we are currently investigating whether this is indeed the case. Finally, we are gearing up towards trialling green LED therapy in a much larger clinical trial for fibromyalgia and other debilitating chronic pain conditions.”
Results of the study are detailed in the paper “Long-lasting antinociceptive effects of green light in acute and chronic pain in rats,” published in the journal Pain.
Written by Sandra Henderson, Research Editor, Novus Light Technologies Today