Skin photobiological effects induced by blue light

In the digital age, understanding the impact of BL on skin is becoming increasingly important. While awareness of UVA and UVB damage is well-established, the study of BL, a relatively new field, is gaining more attention. The widespread use of electronic devices has increased consumer demand for BL protection, even though sunlight is the primary cause of BL-induced photodamage. Despite progress in UVA and UVB protection, the sun protection industry has yet to fully address the challenges posed by BL.

A recent study in the Journal of Dermatologic Science and Cosmetic Technology addresses this gap, exploring BL's impact on skin, including pigmentation, barrier damage, and photoaging. Particularly in skin Fitzpatrick types III and above, BL can cause a long-term tanning effect, while lighter skin colors are less affected. Recent studies have shown that BL exposure causes tanning in the Chinese population and that this effect is proportional to the dose of exposure. In addition, the combined effect of a small amount of UVA and BL caused longer-lasting hyperpigmentation in darker skin. The study also revealed differences in the molecular mechanisms of BL and UVA, including their different targets of action - BL acts on OPN3, while UVA acts on TRPA1 - and the oxidative stress pathways they trigger, with BL producing superoxide, and UVA producing singlet oxygen which further emphasizing the importance of BL protection in sun care. In terms of tanning mechanisms, BL triggers Ca2+ flow through activation of OPN3, which in turn affects the expression of TYR and DCT, ultimately leading to the release of melanosomes, resulting in skin tanning. In terms of oxidative stress, BL-induced generation of reactive oxygen species not only damages mitochondrial DNA and affects cellular respiratory function, but also damages cellular nuclear DNA, which is closely related to inflammatory response, pigmentation, and aging process of the skin. In photoaging, BL activates TRPV1 to generate reactive oxygen species (ROS) and Ca2+ ionic current, which promotes the expression of matrix metalloproteinase (MMP), thereby degrading collagen. Similar to UVA, BL also reduces collagen production and accelerates skin aging by organizing the TGF-β/Smad signaling pathway.

The authors bridge theory and practice, recommending a multifaceted BL protection approach with physical and chemical sunscreens, bioprotective ingredients, antioxidants, and anti-photoaging components. MISTINE's red rice extract is highlighted as a bioprotective example, combating ROS, melanin production, and collagen degradation caused by BL.

Despite growing recognition of BL's impact, the industry lacks a unified assessment standard. The study notes the potential use of the BL Protection Factor (PBF) in cutting-edge research as a standard for BL protection.

This study is significant as it identifies BL's mechanisms of skin damage from a photobiology perspective, offering guidance for BL protection in the sun protection industry and constructive suggestions for establishing BL protection standards.

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Contact the author: Tao Zhang, Research and Development Center, Better Way (Shanghai) Cosmetics Co. Ltd., Shanghai, China, zhangt@mistinechina.com

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