What happens when we get sunburnt?

Exposure to UVB radiation can cause sunburn, premature ageing and carcinogenesis. Image: Losevsky Photo and Video/Shutterstock

Turns out this painful process is an immune response to radiation.

We’ve all had it happen — too long in the Sun and our exposed skin becomes red and painful to touch. This inflammation — a biological response to the ultraviolet (UV) radiation — is actually a consequence of RNA damage to skin cells.

UVB radiation tangles and fractures elements of self non-coding RNA, according to researchers from the University of California, San Diego in the US. Using human cells and a mouse model, they found that our irradiated cells then release this altered RNA.

This provokes the healthy cells to start a process that eventually causes an inflammatory response, with the goal of removing the sun-damaged cells. We experience the painful process as sunburn.

“The inflammatory response is important to start the process of healing after cell death,” says Professor Richard Gallo, one of the authors of the study published in Nature Medicine. “We also believe the inflammatory process may clean up cells with genetic damage before they can become cancer. “Of course, this process is imperfect and with more UV exposure, there is more chance of cells becoming cancerous.”

These findings could possibly lead to a way of blocking this response, which would have implications for various medical treatments. Psoriasis, for example, is treated using UV light, but this increases the risk of skin cancer.

“Our discovery suggests a way to get the beneficial effects of UV therapy without actually exposing our patients to the harmful UV light,” Gallo says. Blocking this process could also benefit people with excessive sensitivity to UV light, such as those suffering from lupus.

However, we still don’t know how gender and skin pigmentation affects the sunburn mechanism. Gallo suggests that genetics appears to be linked to the ability to defend against UV damage.

“We know in our mouse genetic models that specific genes will change how the mice get sunburn. Humans have similar genes, but it is not known if people have mutations in these genes that affect their sun response.”

Source: Eureka Alert

The degrees of skin burns. Image: rob3000/Shutterstock

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