Scientists decode how UV rays damage our skin

Ultraviolet rays weaken bonds between cells in top layer of skin and causes damage

By DTE Staff
Published: Friday 23 August 2019
Photo: Getty Images

Sunscreens, widely used as a first line of defence against skin cancer, can safeguard even the deepest layers of your skin from Sun’s ultraviolet (UV) rays, claims a study.

Exposure to UV rays emitting from the Sun have been known to cause sunburns and lead to melanoma, a potentially deadly form of skin cancer. But, in the study, researchers from Binghamton University explored the mechanism underlying the damage. 

They found that the UV rays weakens the bonds between cells in the stratum corneum — the top layer of skin — and causes damage.

The rays disperse the proteins in the corneodesmosomes, which helps the cells to adhere together, and leads to peeling of skin, according to the study published online in the Journal of the Mechanical Behavior of Biomedical Materials.

Corneodesmosomes are the main intercellular adhesive structures found in the stratum corneum.

To understand, the researchers used female breast skin samples. When they subjected the samples to more UV radiation, they found that “the dispersion of these corneodesmosomes was increasing”, said Zachary W Lipsky, a biomedical engineering doctoral student at the University.

“They’re supposed to be these nice little distinct points surrounding cells, but with more irradiation, they essentially look exploded, moving away from their position. We conclude that because of the disruption of these corneodesmosomes, it damages the skin’s structural integrity,” Lipsky added.

Protecting the stratum corneum, throughout all seasons, is important as it blocks different bacteria from entering the body and causing infections. Sunscreens can, thus, play a significant role in protecting the skin, the researchers said.  

“We’re trying to push the message to use sunscreen not just for preventing skin cancer, but also to keep the integrity of your skin so you don’t get infections or other problems,” Lipsky said.

The team, further, subjected the samples to various wavelengths of UV radiation to understand what kind of ultraviolet radiation is the worst and how it damages human skin.

Depending on wavelength and photon energy, UV radiation — which the human eye can’t perceive — are of four types:

  • Ultraviolet A (315 to 400 nanometres wavelength) — It is not absorbed by the Earth’s ozone layer
  • Ultraviolet B (280 to 315 nanometres wavelength) — It is mostly absorbed before it reaches us
  • Ultraviolet C(200 to 280 nanometres wavelength) — It is completely absorbed by the ozone layer
  • Vacuum ultraviolet(100 to 200 nanometres wavelength) — It occurs on Earth only under laboratory conditions and is very close to the X-ray spectrum.

No UV range was found more harmful than the other. But the damage depends on the amount of UV energy that the skin absorbs, the researchers said.

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