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

最近，强脉冲光(IPL)和发光二极管(LED)等可见光(VL)被引入无痛、非研磨性光疗，以逆转皮肤的光老化，如皱纹和扁豆。然而，VL辐射调节这些老化皮肤变化的确切基本机制尚未得到证实。在这里，我们利用原代培养的人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产量均显著增加。此外，红、黄、蓝三色LED还能刺激细胞修复DNA氧化损伤的能力，其中8-oxo-G的修复能力通过宿主细胞对报告质粒的重新激活来评估。暴露在红色或蓝色LED下的人体3D皮肤样组织上的黑色素生成受到抑制，而皮肤组织学上没有受到损害。这些发现表明，LED灯可通过激活真皮皮肤成纤维细胞、提高DNA修复能力以防止DNA氧化损伤和抑制黑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.