Why does the skin turn red after a sunburn?

Whenwe burn our skin due to the action of ultraviolet (UV) raysfrom the sun, the biological response by the immune system leads toredness,pain, itchingisswelling. A team of researchers at the University of California, San Diego, has shown that this process is due to damage to the RNA of skin cells. The conclusions are published inNature Medicine.

Using human and mouse cells, Richard L. Gallo and his colleagues observed thatUVB radiation damages microRNA noncoding elements-a special type of RNA inside cells. Irradiated cells release this altered RNA, causing neighboring healthy cells to initiate an inflammatory response, in order toget rid of sun damaged cells.

“Theinflammatory response is important to start the healing processafter cell death, “says Gallo. Furthermore, the inflammatory process can kill cells with genetic damage before they become cancerous. However, we must not forget this process is imperfect, and repeated exposure to rays UV causes more chances that the defense of the cells is insufficient and a cancerous process starts.

According to Gallo, it is still unknown how gender, skin pigmentation, and individual genetics can affect the body’s response after a sunburn. “Genetics is closely linked to the ability to defend against UV rays; we know which genes, in our mouse models, change in the face of sunburn. Humans have similar genes, but it is not known whether these genes influence in the same way before sunburn “, concludes the researcher.