14 DAY TRIAL // Sunbathing and tanning beds might give folks the perfect skin tone, but they can also cause skin cancer. This is because the ultraviolet light that people are exposed to when sunbathing or when lying inside a tanning bed damages cell DNA.
In a study published in yesterday's issue of the journal Science, Yale University researchers warn that, as surprising as this may sound, ultraviolet radiation continues to damage the skin even after exposure.
What they mean is that, even after leaving the beach or their favorite beauty salon, people are not safe from the health risks that come with exposure to ultraviolet light. On the contrary, their skin continues to experience damage for several hours.
A better understanding of how sunlight affects the skin
In the report detailing their work, Yale University specialist Douglas E. Brash and his colleagues explain that the reason ultraviolet light can cause skin cancer is that exposure to it translates into damage to the DNA in cells.
More precisely, evidence indicates that ultraviolet light damages specific cells dubbed melanocytes, which serve to make the melanin that gives skin its distinctive color. By damaging the DNA of these cells, ultraviolet light encourages abnormal tissue growth.
While experimenting on laboratory mice, the Yale University specialists found that, when exposed to ultraviolet light, melanocytes containing the pigment melanin witnessed the DNA inside them being bent and twisted up to the point that it was impossible to read correctly.
What's interesting is that the melanocytes were found to continue producing such damaged DNA for several hours after being exposed to ultraviolet light. Simply put, the cells carried on experiencing the negative effects of exposure to ultraviolet light in the dark.
How sunlight damages the skin even in the dark
Writing in the journal Science, researcher Douglas E. Brash and his team explain that, when its home cell is exposed to ultraviolet radiation, the pigment melanin interacts with two enzymes and produces energy. It is this energy that acts on cell DNA, damaging it.
As the scientists put it, “The UV light activated two enzymes that combined to ‘excite’ an electron in melanin. The energy generated from this process - known as chemiexcitation - was transferred to DNA in the dark, creating the same DNA damage that sunlight caused in daytime.”
In light of these findings, the researchers recommend that efforts be made to find a way to limit the effect that ultraviolet light has on the skin even after exposure. Specifically, the scientists imagine designing evening-after sunscreens that would block the reactions shown to cause DNA damage.
