Sunburn pain discovery could lead to better arthritis treatments

Some of us today are suffering from one of summer's few downsides--sunburn, which is caused by having too much fun outdoors. However, U.K. researchers studying sunburns--or, as the condition is known in science circles, UVB irradiation--have found a molecule that controls how sensitive one is to sunburn pain. But this research goes well beyond the uncomfortable sting of sunburn and may help scientists develop new drugs that target pain caused by other inflammatory conditions--such as arthritis.

Here's what scientists at King's College London found in research funded by the Wellcome Trust. There is a molecule known as CXCL5 that's part of a family of proteins called chemokines. They are responsible for mediating pain as they send inflammatory immune cells to the site of the sunburn. The scientists know this fact after recruiting some brave, healthy human volunteers to agree to be blasted with UVB irradiation on small patches of skin--without, presumably, the fun in the sun that goes along with normal exposure. Biopsies revealed CXCL5 was significantly over-expressed in the human volunteers and a few unwilling rat subjects. In further tests on rats, the scientists showed that a neutralizing antibody targeting CXCL5 significantly reduced the pain.

"These findings have shown for the first time the important role of this particular molecule in controlling pain from exposure to UVB irradiation," London researcher Steve McMahon said in a news release. "But this study isn't just about sunburn--we hope that we have identified a potential target which can be utilized to understand more about pain in other inflammatory conditions like arthritis and cystitis.

"I'm excited about where these findings could take us in terms of eventually developing a new type of analgesic for people who suffer from chronic pain."

One other unique aspect to this research is that the scientists did it a bit backwards from the norm. They identified the mediators first in humans, then explored them further in rats.

- read the release
- Reuters filed this story