1399 Blue light disrupts circadian rhythm at night causing direct effects on skin cells

Abstract

Since entering the industrialized age, we have introduced artificial lights in our life, this is called Light Pollution. Artificial light has been created in order to lengthen the days either for work or for our modern life. This causes a loss of the normal evening/night reduction in light that used to give clues to our body to be ready for sleep and other functions, impacting our natural circadian rhythm. Our biological functions rhythm has been found to be dependent on us being exposed to daylight and darkness and the disruption of this rhythm by light pollution has been now shown to have profound health effects. Entering in the 21st century, light pollution has continued to increase with the rapid expansion of personal electronic devices, which are a potent source of blue light, the strongest signal for us to stay awake and alert, and not to fall asleep. The skin, as the largest organ in our body, is directly exposed to the environment/light and serves as a key sensor and a protective barrier. Each skin cell contains clock genes that control and synchronize cellular activities for optimal benefits to the skin. During the day most cellular activities are used to protect the skin, while during the night they are used mostly to restore, repair and regenerate the tissue. When skin cells become out-of-sync they lose some ability to repair and accumulate more damages. It is critical to continually restore this cellular synchronization in order to keep skin healthy and young. Studying skin circadian rhythm, we have been looking for the different factors that push skin cells out-of-sync and more specifically in light pollution, in particular the influence of blue light. Our results show that skin cells can see and are very sensitive to blue light, which has a direct impact on Per-1 clock gene level as well as free radical production. This, ultimately, will result in a skin desynchronization with a loss of circadian rhythm and acceleration of skin aging.