Green LED Light Therapy Shows Potential to Treat Chronic Pain

Green LED Light Therapy Shows Potential to Treat Chronic Pain

Green LED (light-emitting diodes) therapy may represent a novel, nondrug strategy for managing pain, with important implications for patients with fibromyalgia.

The study with the findings, titled “Long-lasting antinociceptive effects of green light in acute and chronic pain in rats,” was published in the journal Pain.

Chronic pain refers to pain that typically lasts for more than three months or past the time of normal tissue healing, according to the Centers for Disease Control and Prevention (CDC). Chronic pain can be the result of an underlying medical disease or condition, injury, medical treatment, inflammation, or an unknown cause.

The prevalence of chronic pain varies, but according to CDC estimates, 14.6 percent of adults in the United States have current widespread or localized pain lasting at least three months.

Treatments for chronic pain are inadequate, and new options are needed. Nonpharmaceutical approaches are especially attractive with many potential advantages, including safety.

“Chronic pain is a serious issue afflicting millions of people of all ages,” Mohab Ibrahim, the study’s first author and assistant professor of anesthesiology and pharmacology at the University of Arizona (UA), said in a news release.

“Pain physicians are trained to manage chronic pain in several ways, including medication and interventional procedures in a multimodal approach,” he said. “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.”

Light therapy is one nondrug approach that has been suggested as beneficial in certain medical conditions such as depression. But it had not been explored in the treatment of pain.

Ibrahim and colleagues examined the effects of green LED in rats with neuropathic pain.

One group of rats was exposed to green LED light (eight hours a day, wavelength 525 nm), while another group was exposed to room light and fitted with contact lenses that allowed the green spectrum wavelength to pass through.

Both groups were found to benefit from green LED exposure.

In comparison, 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 green LED exposure.

Rats receiving green LED light showed significantly more tolerance for thermal and tactile stimulus compared to rats that were not exposed to green LED. There were no apparent side effects and the motor performance of the animals was not impaired by the green LED light.

“While the results of the green LED are still preliminary, it holds significant promise to manage some types of chronic pain,” Ibrahim said.

The beneficial effects lasted for four days after the final exposure.

“While the pain-relieving qualities of green LED are clear, exactly how it works remains a puzzle,” said 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.”

The results indicate that green LED light can change the levels of substances that may inhibit pain and perhaps reduce inflammation of the nervous system.

The team is currently conducting a clinical trial using green LED therapy in people with fibromyalgia to see whether this type of light therapy can ease participants’ pain when used alone or combined with low-dose analgesics or physical therapy.

9 comments

  1. Denise Bault says:

    Clicked on the actual article to read, but was “not allowed to.” Unfortunate. Why have a link if you’re not allowed to access it? However, I do know of at least one “RAT” who would like to be part of a clinical trial!

  2. Em says:

    Too this approach I say it is unfounded and very little is known. There have been instances of other therapies that are pure bull. End of comment.

  3. I have s very open mind and would be willing to try anything. Light sensitivity is very well known and felt by people with fibromyalgia. I know that overuse of certain lights do affect my nervous system,cause stress and this can be felt as pain. This is a great start and I’d love to try this out

  4. StevefromMA says:

    Ok,
    I bought the journal article for eight bucks and read it thoroughly and have much experience doing this. These people are top notch researchers who systematically tracked effects down to the biochemical and genetic level, albeit for rats. Their article gave the exact lights they used so I bought them, fifty bucks, and from the vid got enough info from the elderly woman on how they ran the small human trial, apparently unpublished as of yet. I have sitting in the light about two hours daily for a week, no effect yet, but it’s bright enough to read and I’ll continue until I’m sure it doesn’t work for me. The rat research was very impressive at all levels and the two guys seemed concerned and sincere to me,

        • StevefromMA says:

          This part of the article tells where they and I got the lights, Google for phone umber, cost about fifty bucks for 25 feet of lights, I think. I made a frame for them, sat under a few hours daily for a month and read. Pleasant but no effect. Worth a try IMO, no harm, worked on rats and sample volunteers.

          “Few studies have investigated possible effects of light therapy on pain. A randomized clinical trial investigated the effect of bright light exposure in managing nonspecific back pain where patients received light exposure once a week for 3 weeks reduced pain as assessed by the Brief Pain Inventory suggesting an active role for light in controlling pain.43 Preclinical studies on the possible modulation of pain by light therapy have not been reported. Here, we investigated the effect of light in modulation of acute nociception as well as in a model of chronic neuropathic pain. We found that green light produced antinociceptive and antihyperalgesic effects that involved descending, opioid- sensitive inhibition.
          2. Methods
          2.1. Animals
          Pathogen-free, adult, male and female Sprague Dawley (SD) as well as male Long Evans (LE) rats (weight at testing 250-350 g; Harlan–Sprague–Dawley, Indianapolis, IN) were housed in a climate-controlled room on a 12-hour light/dark cycle and were allowed to have food and water ad libitum. All procedures were approved by the University of Arizona Animal Care and Use Committee and conformed to the guidelines of the National Institutes of Health (publication no. 80–23, 1966) for the use of laboratory animals. All behavioral experiments were conducted by experimenters blinded to the treatment conditions. The experiments were replicated a minimum of 2 times with independent cohorts of animals.
          2.2. Chemicals
          All experimental compounds, doses, sources, and catalog numbers are described in Table 1.
          2.3. Light-emitting diodes
          Visible-spectrum light-emitting diode (LED) flex strips were purchased from ledsupply.com (Randolph, VT). The specifi- cations of the LEDs were (1) #LS-AC60-6-BL, 472 nm wavelength (ie, blue), 8 W, 120 V, 120 ̊ beam angle; (2) #LS- AC60-6-GR, 525 nm wavelength (ie, green), 8 W, 120 V, 120 ̊ beam angle; and (3) #LS-AC60-66-WH, white, 9.6 W, 120 V, 120 ̊ beam angle. Light-emitting diode strips were affixed to the outside of clear plastic cages that housed the rats so as to prevent the strips from being chewed. Rats were exposed to the various LEDs in these cages with full access to food and water in a dark room devoid of any other source of light. After behavioral assessment, the rats were returned to their cages for additional LED exposure. At the end of daily testing, the rats were returned to their regular animal room where they were exposed to room
          Because there are no previously published data reporting the effects of green LEDs on antinociception in rats, as a first step, we performed “pilot” experiments using a fixed amount (330 lux— which represents 1 full “strip”) of green LEDs over time, noting that antinociception developed only after 3 to 5 hours of exposure for at least 3 days. This antinociception continued to gradually increase over the next 2 days of exposure, reaching its zenith between days 4 and 5 (data not shown). The bulk of the studies were thus performed with 8 hours daily exposure for 5 days. Next, we performed a light-intensity vs antinociception analysis, which revealed that lower lux intensity was more effective than higher lux exposure for 8 hours daily for 5 days. These pilot experiments formed the basis of the exposure paradigm used in these studies—lux level, number of hours of exposure per day, and number of days of exposure.
          2.4. Thermal sensory thresholds
          Paw withdrawal latencies (PWLs) used were determined as described by Hargreaves et al.28 Rats were acclimated within Plexiglas enclosures on a clear glass plate maintained at 30 ̊C. A radiant heat source (high-intensity projector lamp) was focused onto the plantar surface of the hind paw. When the paw was withdrawn, a motion detector halted the stimulus and a timer. A maximal cut-off of 33.5 seconds was used to prevent tissue damage.
          2.5. Tactile thresholds
          The assessment of tactile sensory thresholds was determined by measuring the withdrawal response to probing the hind paw with a series of calibrated fine (von Frey) filaments. Each filament was applied perpendicular to the plantar surface of the paw of rats held in suspended wire mesh cages. Withdrawal threshold was determined by sequentially increasing and decreasing the stimulus strength (the “up and down” method), and data were analyzed with the nonparametric method of Dixon, as described by Chaplan et al.,12 and expressed as the mean withdrawal threshold.
          2.6. Elevated plus maze
          The elevated plus maze (EPM) consists of 4 elevated (50 cm) arms (50 cm long and 10 cm wide) with 2 opposing arms containing 30 cm high opaque walls. Elevated plus maze testing occurred in a quiet testing room with ambient lighting at ;500 lux. On the day of testing, the rats were allowed to acclimate to the testing room for 20 minutes.”

  5. It’s much too early to expect a cure to pain by green LEDs. I would wait until peer-reviews and peer-copies of the experiment(s) are done. It reminds me of the good-and-bad results from consistent wine drinking (or low-dose aspirin taking)…

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