Chiarelli-Neto Orlando, Ferreira Alan Silva, Martins Waleska Kerllen, Pavani Christiane, Severino Divinomar, Faião-Flores Fernanda, Maria-Engler Silvya Stuchi, Aliprandini Eduardo, Martinez Glaucia R, Di Mascio Paolo, Medeiros Marisa H G, Baptista Maurício S
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas-USP, São Paulo, Brazil.
PLoS One. 2014 Nov 18;9(11):e113266. doi: 10.1371/journal.pone.0113266. eCollection 2014.
Protecting human skin from sun exposure is a complex issue that involves unclear aspects of the interaction between light and tissue. A persistent misconception is that visible light is safe for the skin, although several lines of evidence suggest otherwise. Here, we show that visible light can damage melanocytes through melanin photosensitization and singlet oxygen (1O2) generation, thus decreasing cell viability, increasing membrane permeability, and causing both DNA photo-oxidation and necro-apoptotic cell death. UVA (355 nm) and visible (532 nm) light photosensitize 1O2 with similar yields, and pheomelanin is more efficient than eumelanin at generating 1O2 and resisting photobleaching. Although melanin can protect against the cellular damage induced by UVB, exposure to visible light leads to pre-mutagenic DNA lesions (i.e., Fpg- and Endo III-sensitive modifications); these DNA lesions may be mutagenic and may cause photoaging, as well as other health problems, such as skin cancer.
保护人类皮肤免受阳光照射是一个复杂的问题，涉及光与组织相互作用中尚不明确的方面。一个长期存在的误解是可见光对皮肤是安全的，尽管有几条证据表明并非如此。在这里，我们表明可见光可通过黑色素光敏化和单线态氧（1O2）生成来损伤黑素细胞，从而降低细胞活力、增加膜通透性，并导致DNA光氧化和坏死性凋亡细胞死亡。紫外线A（355纳米）和可见光（532纳米）以相似的产率使1O2光敏化，并且褐黑素在生成1O2和抵抗光漂白方面比真黑素更有效。虽然黑色素可以保护细胞免受紫外线B诱导的损伤，但暴露于可见光会导致前诱变DNA损伤（即对Fpg和Endo III敏感的修饰）；这些DNA损伤可能具有诱变作用，并可能导致光老化以及其他健康问题，如皮肤癌。
