Green Light for Pain Relief

Despite chronic pain affecting approximately one third of the adult population in the US, the number of treatment options has remained relatively stagnant for decades. The Translational Scientist previously addressed the challenging nature of the search for new analgesics – and our experts urged other researchers to join the quest for novel therapeutic options (1). Now, a team at the University of Arizona has risen to the challenge and shown that light therapy could have uses beyond treating depression, jaundice, and skin conditions.

The researchers bathed rats under LED light at various wavelengths in the visible spectrum for 8 hours a day and compared their tolerance to neuropathic pain. Rats under 525 nm (green light) exhibited significant long-lasting antinociception (2).

To probe the mechanism, rats were fitted with opaque contact lenses and exposed to green light, or fitted with green contact lenses and exposed to room light; in the former, antinociception was prevented, but in the latter antinociception was exhibited, strongly indicating the role of the visual system.

More clinical work will be necessary to assess the potential of green LED therapy in the management of acute and chronic pain – but the lack of apparent side-effects, coupled with the low cost and wide availability of LEDs, sounds like a compelling treatment option for millions of sufferers worldwide. Perhaps equally importantly, the work shows that non-pharmacological approaches do exist and are worth seeking out...