We all know that for human skin to tan it takes several days of sun exposure. The downside of this process is that prolonged exposure to solar ultraviolet (UV) rays, in addition to making us tan, damages the DNA of skin cells. Now a team of researchers from Brown University (USA) has identifieda much faster way to achieve skin pigmentation. As published by the researchers in the journalCurrent Biology, the research results could affect the design of sunscreens in the future.
“Our work shows thata UV receptor allows skin cells to detect and respond immediately to UV light“explains Elena Oancea, co-author of the study. This immediate response occurs in a matter of seconds after being exposed to UVA light, which represents about 95 percent of the ultraviolet radiation on the Earth’s surface, while UVB rays add up to the another 5 percent.
Oancea’s team found thatExposure of pigment-producing human skin cells to UVA rays leads to early melanin synthesisin a process that involves the release of calcium. They also observed that the skin’s response depends on therhodopsin, a light-sensitive molecule that is also found in the retina of the eye. “Both the eyes and the skin – the only two organs constantly exposed to solar radiation – use very similar molecular mechanisms to decipher light,” Oancea clarifies.
The authors suggest thatanticipated melanin production, which is only activated by the activation of rhodopsin, provides afirst line of defense against UV light. If this is the case, “this route and its protection capacity must be taken into account in the design and use of broad spectrum sunscreens”, the researcher emphasizes.
