Ultraviolet Rays Can Harm Skin Hours Later, Even in the Dark
Ultraviolet Rays Can Harm Skin Hours Later, Even in the Dark – Researchers say ultraviolet rays can continue to harm skin even in the dark, inflicting cancer-causing DNA damage hours after people have left the sunshine or tanning bed.
In experiments on skin cells from mice and humans, the researchers found that the cells experienced a certain type of DNA damage not only immediately after exposure to ultraviolet A rays, but for hours after the UVA lamps were turned off. UVA rays make up about 95 percent of the ultraviolet radiation that penetrates Earth’s atmosphere.
To the researchers’ surprise, they found that the reason for this continuing damage is that melanin — the pigment that gives skin and hair their color, and is usually thought of as a protective molecule because it blocks the ultraviolet rays that damage DNA — can itself cause damage to DNA. This new finding reveals that melanin can both help prevent and cause cancer, supporting a few past studies suggesting that melanin is associated with skin cell damage.
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