Scientists discover molecule responsible for sunburn

Sunburn is nature's warning to the sunworshipper to seek shade. Picture: PA

Blocking this molecule, named TRPV4, which is abundant in the epidermis, greatly protects the skin against the painful effects of sunburn, tests revealed.

Lead author, Professor Wolfgang Liedtke, neurologist at Duke University School of Medicine in North Carolina, said the findings could lead to the development of new types of creams to provide extra protection from the sun’s rays.

The study could also help look for new ways to treat the effects of long-term sun damage as well as other skin diseases.

He said: “We have uncovered a novel explanation for why sunburn hurts. If we understand sunburn better, we can understand pain better because what plagues my patients day in and day out is what temporarily affects otherwise healthy people who suffer from sunburn.”

Most sunburn is caused by ultraviolet B radiation, also known as UVB, which is good for the body in small doses, providing vitamin D and decreasing the risk of certain diseases.

However, too much exposure to UVB damages the DNA in people’s skin cells and increases the likelihood of them developing skin cancer. In this way, sunburn is nature’s warning sign to sun worshippers to seek shade.

The new study used genetically engineered mice that were missing the crucial TRPV4 molecule in their skin. These mice had their hind-paws, where the skin is most similar to humans, exposed to UVB.

Normal mice exposed to the same rays suffered from soreness and blistering, but the mutant mice showed very little damage. Applying a specially manufactured solution designed to block the TRPV4 molecule to the paws of the normal mice was effective in stopping the pain and damage to the skin.

Moving on to human skin samples, researchers were able to find that exposure to UVB increased the amount of TRPV4 in the skin – strongly suggesting the same process is responsible for sunburn in humans.

A study released earlier this year by Edinburgh University researchers found that the benefits of exposure to sunlight, such as lowered blood pressure, decreased risk of strokes and increased vitamin D production, broadly outweigh the extra risks of skin cancer.

However, this was followed a month later by the results of a survey by Macmillan Cancer Support, which found that nearly half of Scots get sunburn deliberately to try to get a “deeper tan”, even though getting sunburnt once every two years can triple the risk of skin cancer.