STUDY: UV rays continue to harm skin hours after exposure
Thursday, February 19, 2015, 7:03 PM - A new study out of Yale University suggests the majority of damage the sun's ultraviolet (UV) radiation does to skin occurs hours after exposure.
DNA damage usually begins less than a second after UV rays make contact with the skin, but the new study reveals the majority of the damage occurs at least three hours later.
Researchers exposed melanocytes -- specialized human skin cells that make the melanin that give skin its colour -- to UV radiation.
The radiation triggered a type of DNA damage known as a cyclobutane dimer (CPD). Cells that lacked melanin only experienced DNA damagedduring exposure, while cells with melanin continued to produce CPDs for hours.
Skin cells from mice produced similar results, leading researchers to believe that melanin can be both protective and carcinogenic.
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“If you look inside adult skin, melanin does protect against CPDs. It does act as a shield,” study author Douglas E. Brash said in a statement.
“But it is doing both good and bad things.”
UV radiation damages the skin's DNA which can eventually lead to skin cancer.
The team says the findings may lead to the development of preventative treatments, like "evening-after" sunscreens that prevent post-exposure damage.
The complete study has been published in the journal Science.
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