Scientists unearth secret behind skin tan

Have you ever wondered how your skin gets a nice tan after a week of frolicking in the sun-kissed beaches of Goa and how it fades in a month?

Indian biologists now claim to know the answer, which may lead to the development of a therapy against leprosy. Besides, it would strengthen the ongoing battle against skin cancer. “Our aim would be to research on a new therapy for leprosy, exploiting the pathway we found,” Rajesh S Gokhale, director of Institute of Genomics and Integrative Biology (IGIB), Delhi, which led the study, told Deccan Herald.

One of the indications of leprosy is white patches on the skin, which happens when cells producing skin pigment melanin stop functioning. This is where the Indian team wants to chip in. Human skin gets its characteristic colour from melanin, packed in small granules that serve as soldiers shielding the DNA from harmful rays of the sun.

It is required in the body because too much sun can cause sunburn and cancer.

Whenever our body is exposed to the sun, these granules increase in number, strengthening the protective shield. It results in skin tanning. The tan remains for 28 days after which the skin gets back its colour.

“Our study shows a protein named interferon-gamma is a crucial factor secreted by immune cells that maintains these checks and balances in human skin. It helps bring back pigmentation to a normal state,” said Gokhale. The research findings were published in the January 28 issue of “Proceedings of National Academy of Sciences”.

The IGIB team, along with researchers from National Institute of Immunology, Jawaharlal Nehru University and Ram Manohar Lohia Hospital here, besides National Chemical Laboratory, Pune found that the interferon pathway was involved in maintaining pigmentation balance in the skin.