Too much sun results in RNA damage to your skin cells

We are reminded time and time again of how much sunburn hurts. But what exactly happens during this reddish and painful experience?

Researchers at the University of California's San Diego School of Medicine have found, using both human skin cells and mouse models, that the biological mechanism of sunburn - an immune response to ultraviolet radiation - is the result of RNA damage to skin cells.

Reporting their findings in Nature Medicine, the scientists say it could open the way to eventually blocking the inflammatory process, and have implications for a range of medical conditions and treatments.

RNA, or ribonucleic acid, is a type of molecule very similar to DNA, the hereditary material in humans and almost all other living organisms. RNA plays an active role in cell processes such as biological reactions and protein synthesis.

Principal investigator Dr Richard L. Gallo and his team found that UVB radiation - the part of the electromagnetic spectrum that causes sunburn - fractures and tangles elements of a special type of RNA inside the cell that does not directly make proteins. Irradiated cells release the altered RNA, causing healthy, neighbouring cells to start a process that results in an inflammatory response intended to remove the sun-damaged cells. This process is what we see and feel as sunburn.

'The inflammatory response is important to start the process of healing after cell death,' says Gallo, professor of medicine and paediatrics at UC San Diego School of Medicine.