Unlocking the Mystery of Post-Sun Exposure Tanning: Tel Aviv University’s Pioneering Study Reveals the Science of Post-Beach Tanning
For many beachgoers, it’s a familiar scenario: after hours of soaking up the sun, you return home, only to notice that your skin has changed color, but not immediately. A groundbreaking study from Tel Aviv University has now unraveled the scientific intricacies behind this delayed tanning process that occurs after sun exposure or post-beach tanning.
The research findings shed light on the mechanism responsible for this intriguing phenomenon of post-beach tanning. It turns out that after sun exposure, our bodies prioritize repairing DNA damage in the skin cells before triggering the mechanism that leads to skin pigmentation, commonly recognized as tanning.
Conducted in collaboration with researchers from Tel Aviv University, Wolfson Medical Center, the Weizmann Institute of Science, the University of California, and Paris-Saclay University, this study was spearheaded by doctoral student Nadav Elkoshi and Prof. Carmit Levy from the Department of Human Molecular Genetics and Biochemistry at Tel Aviv University’s Faculty of Medicine. Their findings were published in the Journal of Investigative Dermatology, part of the Nature Group.
Elkoshi explains, “We have two mechanisms designed to protect the skin from exposure to dangerous UV radiation. The first mechanism repairs the DNA in the skin cells damaged by the radiation, while the second mechanism involves increased production of melanin, which darkens the skin to shield it from future radiation exposure. In our study, we discovered why the tanning phenomenon does not occur immediately when the body is exposed to the sun, but only following a delay.
It turns out that the mechanism that repairs our DNA takes precedence over all other systems in the cell, temporarily inhibiting the pigmentation mechanism. Only after the cells repair the genetic information to the best of their ability do they begin to produce the increased melanin.”
To validate their hypothesis of post-beach tanning, the Tel Aviv University researchers activated the DNA repair mechanism in both animal models and human skin tissues. Remarkably, a tan developed even without any exposure to UV radiation, providing solid evidence for their findings.
Prof. Carmit Levy elaborates on the process of post-beach tanning, stating, “The genetic information must be protected from mutations, so this repair mechanism takes precedence inside the cell during exposure to ultraviolet radiation from the sun. The DNA repair mechanism essentially tells all the other mechanisms in the cell, ‘Stop everything, and let me work in peace.’ One system effectively paralyzes the other, until the DNA correction reaches its peak, which occurs a few hours after the UV exposure.
Only then does the pigment production mechanism get to work. In our previous research, we showed that a protein called MITF, which is activated during exposure, is responsible for regulating these two mechanisms. In the current study we show that another protein, called ATM, which plays a key role in DNA repair, activates one mechanism while disabling the other. This process likely harnesses the pigmentation mechanism’s components to maximize the chances of the cell surviving without mutations following radiation exposure.”
Prof. Levy concludes by emphasizing the broader implications of this discovery, stating, “This scientific discovery has revealed a molecular mechanism that could serve as a foundation for further research on post-beach tanning that may lead to innovative treatments that will provide maximum protection of the skin against radiation damage; in the long run, it may even contribute to the prevention of skin cancer.”