Analysis of the effect of visible light on photoaged skin focusing on DNA repair

可见光（VL），如强脉冲光（IPL）和发光二极管（LED）最近被引入到无痛、非磨蚀性光疗中，以逆转光老化皮肤，如皱纹和小雀斑。然而，VL照射调节这些老化皮肤变化的精确基本机制尚未得到证实。本研究利用人原代培养成纤维细胞和三维皮肤样组织结构，研究了LED对细胞增殖、透明质酸产生、DNA修复能力和黑色素生成的影响。红色和蓝色LED照射后，细胞增殖率和透明质酸的产生明显增加。此外，红色、黄色和蓝色LED可以刺激细胞修复氧化DNA损伤的能力，包括8-oxo-G，通过宿主细胞报告质粒的再激活来评估。暴露在红色或蓝色LED下的人体三维皮肤样组织上的黑色素生成受到抑制，而皮肤没有组织学损伤。这些发现表明，LED光可以通过激活真皮皮肤成纤维细胞、增加DNA修复氧化DNA损伤的能力和抑制黑色素生成的机制来帮助皮肤恢复活力。

Visible light(VL) such as intense pulsed light(IPL) and light emitting diodes(LED) have been recently introduced to the painless, nonabrasive phototherapy to reverse photoaging skin such as wrinkles and lentigines. However the precise basic mechanisms on which VL irradiation can modulate these aged skin changes has not yet been proven. Here, we examined the effect of LED on cell proliferation, production of hyaluronic acid, DNA repair ability and melanogenesis by use of the human primary cultured fibroblasts and the 3-D skin-like tissue structure. A rate of cell proliferation and production of hyaluronic acid from the cells were significantly increased after red and blue LED irradiation. In addition, red, yellow and blue LED could stimulate the ability to repair oxidative DNA damage including 8-oxo-G of the cells assessed by host cell reactivation of the reporter plasmid. Melanogenesis was inhibited on the human 3-D skin-like tissue exposed to red or blue LED without no histologically damage of the skin. These findings suggest that LED light can be useful for skin rejuvenation through mechanisms of activating dermal skin fibroblast, increasing DNA repair ability to oxidative DNA damage and suppressing melanogenesis.