Department of Dermatology, Huashan Hospital, Fudan University, Shanghai 200040, PR China.
Department of Dermatology, Huashan Hospital, Fudan University, Shanghai 200040, PR China.
J Dermatol Sci. 2018 Jan;89(1):11-18. doi: 10.1016/j.jdermsci.2017.10.001. Epub 2017 Oct 11.
Melasma is a common hyperpigmentation skin disease on face. Light-emitting diode (LED) photomodulation (585nm) is reported to be effective for the treatment of melasma. However, whether and how LED photomodulation would influence melanogenesis of human epidermal melanocytes (HEMs) is unknown.
To evaluate the effects of LED photomodulation (585nm) on melanogenesis in HEMs.
HEMs were irradiated with fluences of 0, 5, 10 and 20J/cm 585nm LED light. After 5-day treatment, cell viability was analyzed by CCK-8 assay, and apoptosis was assessed by Annexin V APC assay. Melanin content and tyrosinase activity were measured by spectrophotometer. Melanosome stage and autophagosomes were determined under transmission electron microscope (TEM). The formation of autophagic punctate structures was observed under confocal microscope. RT-PCR and western blotting were used to assess the expression of relative mRNA and protein levels.
Yellow light LED 585nm had no effects on HEMs cell viability and apoptosis. Treatment with LED 585nm from 5J/cm to 20J/cm inhibited melanosome maturation, decreased melanin content and tyrosinase activity. Inhibition was accompanied by the decreased expression of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1) and microphthalmia-associated transcription factor (MITF) on both mRNA and protein levels. Autophagosomes were observed under TEM. Autophagic punctate structures of microtubule-associated protein light chain 3 (LC3) proteins were induced by LED 585nm light. The configuration change of LC3 from LC3-I to LC3-II, and the degradation of p62 protein were observed after LED 585nm. Furthermore, we also revealed that the anti-melanogenic effect of LED 585nm photomodulation was reversed by 3-Methyladenine (3-MA), which inhibits autophagy by blocking autophagosome formation via the inhibition of type III Phosphatidylinositol 3-kinases (PI-3K).
Our finding demonstrated that LED photomodulation with 585nm wavelength suppressed melanin content in HEMs, and the effect was caused by its dose-dependent inhibition on melanogenesis and the induction of HEMs autophagy. This may provide new insights into the efficacy of LED photomodulation in the treatment of hyperpigmentation disorders.
黄褐斑是一种常见的面部色素沉着性皮肤病。据报道，发光二极管（LED）光调制（585nm）对治疗黄褐斑有效。然而，LED 光调制是否以及如何影响人表皮黑素细胞（HEMs）的黑色素生成尚不清楚。
评估 LED 光调制（585nm）对 HEMs 黑色素生成的影响。
用 0、5、10 和 20J/cm 的 585nm LED 光照射 HEMs。经过 5 天的治疗，用 CCK-8 法分析细胞活力，用 Annexin V APC 法评估细胞凋亡。用分光光度计测定黑素含量和酪氨酸酶活性。用透射电子显微镜（TEM）观察黑素体阶段和自噬体。用共聚焦显微镜观察自噬点状结构的形成。用 RT-PCR 和 Western blot 法评估相对 mRNA 和蛋白水平的表达。
黄色 LED 585nm 对 HEMs 细胞活力和凋亡没有影响。用 LED 585nm 处理 5J/cm 至 20J/cm 抑制黑素体成熟，减少黑素含量和酪氨酸酶活性。这种抑制伴随着酪氨酸酶（TYR）、酪氨酸酶相关蛋白-1（TRP-1）和小眼畸形相关转录因子（MITF）在 mRNA 和蛋白水平上表达的降低。TEM 观察到自噬体。LED 585nm 光诱导微管相关蛋白轻链 3（LC3）蛋白的自噬点状结构。在 LED 585nm 光处理后，LC3 蛋白从 LC3-I 转变为 LC3-II，p62 蛋白降解。此外，我们还发现，通过阻断自噬体形成来抑制 III 型磷酸肌醇 3-激酶（PI-3K），LED 585nm 光调制的抗黑色素生成作用被 3-甲基腺嘌呤（3-MA）逆转，后者通过抑制自噬体形成来抑制自噬。
我们的研究结果表明，585nm 波长的 LED 光调制抑制 HEMs 中的黑色素含量，其作用是通过其对黑色素生成的剂量依赖性抑制和诱导 HEMs 自噬引起的。这可能为 LED 光调制治疗色素沉着障碍的疗效提供新的见解。
