People with red hair take longer to heal abrasions and cuts on the skin. A study in mice revealed why. This discovery could help develop more effective treatments for people of all hair colors.

Our hair color is largely determined by our genes. MC1Rwhich encodes a protein that regulates the ratio of black-brown and red-yellow pigment in hair follicles. In people with light brown and dark hair, variants of this gene encode active forms of this protein. In almost all red-haired people, due to mutations in the MC1R gene, this protein has reduced activity or is not active at all. The genetics of blondes are more complex: they can have both active and inactive forms of the protein.

The same protein is also present in our skin, where it has an anti-inflammatory effect. This prompted researchers at the University of Edinburgh to ask: does it interfere with injury healing? This process requires a short-term inflammatory response to clear the wound of germs and dead cells, but if the inflammation is too severe or prolonged, healing is delayed.

Testing on mice

To test this hypothesis, the scientists inflicted identical lesions on the backs of black and red mice. In the latter, the MC1R protein was completely inactive. The results of the experiments were published in the journal PNAS.

After a week, the wounds in the red mice had decreased by an average of 73%, and in the black mice by 93%.

So the scientists decided to test whether increasing the activity of this protein would work as a topical treatment for chronic wounds, like those that take a long time to heal in diabetics.

In this experiment, only black mice were tortured (it is possible to activate at least a partially functional protein; it is useless to act on a “defective” one, like in red mice): wounds were inflicted and treated with an experimental drug.

After a week, they found that the wounds in the treated mice had shrunk by an average of 63%—more than twice as fast as those in the control group, which received saline dressings.

“I think if the wound was half the size, especially in such a short period of time, patients would be delighted,” says pharmacologist Jenna Cash, who led the study.

Further analysis showed that the drug works by reducing the number of inflammatory immune cells.

Because the wound healing process is quite similar in mice and humans, this approach holds promise for treating humans, including redheads, most of whom retain some activity in the MC1R protein; For those for whom this protein does not work, the new technique will definitely not help, Cash warns.

Hope for safety

Drugs targeting this protein are already used to treat conditions such as erythropoietic protoporphyria, in which the skin is overly sensitive to sunlight. Therefore, there is hope for an acceptable safety profile of the new product, the researcher notes.

Further research is needed to confirm this, says Kat Bogie of Case Western Reserve University in Ohio. Human trials are planned for the near future, Cash said.

Future work will need to test how safe and effective the drug is in infected wounds, Bogie adds: “There is a possibility that the drug may interfere with the response to infection, or may have the opposite effect.”

For some redheads, this may come as bad news, especially considering previous studieswhich link red hair color to increased sensitivity to pain. But Cash is confident there is no cause for concern.

“Red-haired people don’t have to worry. “We don’t have data in humans yet, and even if a redhead’s healing was slightly slower, they might not even notice it—the effect would likely be quite small,” she concluded.