Healthy Living

Cause For Sunburn Pain Revealed: Is A Cure On The Way?

Sunburned legs
The discovery from Duke University and the University of California in San Francisco could lead to the end of sunburn pain. Tara Whitsitt, CC BY-NC-ND 2.0

Sunburns are often an unfortunate, and painful, consequence of a nice weekend at the beach. New research in mice has uncovered why sunburns cause pain, which opens the door for new remedies that prevent this process.

"We have uncovered a novel explanation for why sunburn hurts," said study author Dr. Wolfgang Liedtke, an associate professor of neurology and neurobiology at Duke University School of Medicine and whose findings were reported today in the journal PNAS.

This endeavor started by looking for a biological explanation for why sunlight, namely ultraviolet (UV) radiation, harms the skin. Prior work had shown that one protein in the skin — TRPV4 — is responsible for pain sensation after physical damage — like a pin prick. TRPV4 is abundant in the outermost layer of the skin — the epidermis — but nobody had investigated its involvement with sunburns.

The researchers discovered that mice lacking TRPV4 were resistant to tissue injuries — sunburns — caused by UV exposure. As a result, they demonstrated an extremely lowered pain response.

TRPV4 is an ion channel, meaning it serves as a gateway for elemental compounds like calcium and sodium to enter a person's cells.

Read more: Heidi Klum Posts Photo Of Her Sun-Burned Backside: 4 Easy Tips To Keep Your Bum Sunburn Free 

The team found that UV exposure caused skin samples from humans and mice to produce elevated levels of TRPV4. This led to an influx of calcium into cells, which the researchers revealed also brings in another compound called endothelin. Endothelin is known to trigger pain and itching in humans, which may explain why sunburns are often itchy.

To test this further, the scientists then created a salve with a pharamaceutical compound — GSK20 — that blocks TRPV4 channels. Rubbing this lotion onto mice before UV exposure protected them from the pain-inducing, skin-disrupting effects of the sunburn.

"The results position TRPV4 as a new target for preventing and treating sunburn, and probably chronic sun damage including skin cancer or skin photo-aging, though more work must be done before TRPV4 inhibitors can become part of the sun defense arsenal, perhaps in new kinds of skin cream, or to treat chronic sun damage," said co-senior author Dr. Martin Steinhoff, a professor of dermatology and surgery at the University of California in San Francisco

More research is needed to determine whether or not blocking TRPV4 has any side effects, but these early results are very promising.

Read more: Foods That Cure Sunburn: What You Should Eat After a Day At The Beach 

"I think we should be cautious because we want to see what inhibition of TRPV4 will do to other processes going on in the skin," Liedtke concluded. "Once these concerns will be addressed, we will need to adapt TRPV4 blockers to make them more suitable for topical application. I could imagine it being mixed with traditional sunblock to provide stronger protections against UVB exposure."

 

Source: Moore C, Cevikbas F, Pasolli HA, et al. UVB radiation generates sunburn pain and affects skin by activating epidermal TRPV4 and triggering endothelin-1 signaling. PNAS. 2013.

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