Ekanayake Mudiyanselage Swarna, Hamburger Matthias, Elsner Peter, Thiele Jens J
Department of Dermatology and Institute of Pharmacy, Friedrich-Schiller-University, Erfurter Strasse 35, D-07740 Jena, Germany.
J Invest Dermatol. 2003 Jun;120(6):915-22. doi: 10.1046/j.1523-1747.2003.12233.x.
At the outermost surface of human skin, skin surface lipids are first-line targets of solar ultraviolet radiation. Therefore, we hypothesized that ultraviolet A and ultraviolet B irradiation induce photo-oxidation of skin surface lipids. To test this, sebum samples were collected from facial skin of 17 healthy volunteers, weighed, and immediately irradiated with either ultraviolet B or ultraviolet A. Squalene, the major sebum lipid, as well as photo-oxidation products were identified in sebum lipid extracts by high-performance liquid chromatography analysis. Upon ultraviolet A exposures squalene was depleted in a concentration-dependent manner, whereas an unidentified sebum lipid photo-oxidation product was detected. Using high-performance thin layer chromatography, high-performance liquid chromatography, atmospheric pressure chemical ionization mass spectrometry, and nuclear magnetic resonance, unidentified sebum lipid photo-oxidation product was identified as a mixture of squalene monohydroperoxide isomers. Squalene monohydroperoxide isomers purified from sebum were identical with squalene monohydroperoxide isomers synthesized by preparative photo-oxidation of squalene. Squalene monohydroperoxide isomers were formed even after small suberythematogenic doses of ultraviolet A (5 J per cm2). Whereas physiologic baseline levels of squalene monohydroperoxide isomers in human skin were only slightly above detection limits, squalene monohydroperoxide isomer levels were strongly increased by suberythematogenic doses of ultraviolet A both in vitro and in vivo. High-performance liquid chromatography results could be complemented by a straightforward thin layer chromatography method for rapid screening of lipid peroxide formation in human sebum/skin surface lipids. In conclusion, specific squalene monohydroperoxide isomers were identified as highly ultraviolet A sensitive skin surface lipid breakdown products that may serve as a marker for photo-oxidative stress in vitro and in vivo.
在人体皮肤的最外层表面，皮肤表面脂质是太阳紫外线辐射的首要靶点。因此，我们推测紫外线A和紫外线B照射会诱导皮肤表面脂质的光氧化。为了验证这一点，从17名健康志愿者的面部皮肤收集皮脂样本，称重后立即用紫外线B或紫外线A进行照射。通过高效液相色谱分析在皮脂脂质提取物中鉴定出角鲨烯（主要的皮脂脂质）以及光氧化产物。紫外线A照射后，角鲨烯以浓度依赖的方式消耗，同时检测到一种未鉴定的皮脂脂质光氧化产物。使用高效薄层色谱、高效液相色谱、大气压化学电离质谱和核磁共振，将未鉴定的皮脂脂质光氧化产物鉴定为单氢过氧化角鲨烯异构体的混合物。从皮脂中纯化的单氢过氧化角鲨烯异构体与通过角鲨烯的制备性光氧化合成的单氢过氧化角鲨烯异构体相同。即使在小剂量亚红斑量的紫外线A（每平方厘米5焦耳）照射后也会形成单氢过氧化角鲨烯异构体。虽然人体皮肤中生理基线水平的单氢过氧化角鲨烯异构体仅略高于检测限，但在体外和体内，亚红斑量的紫外线A照射均会使单氢过氧化角鲨烯异构体水平大幅升高。高效液相色谱结果可以通过一种直接的薄层色谱方法得到补充，用于快速筛查人皮脂/皮肤表面脂质中脂质过氧化物的形成。总之，特定的单氢过氧化角鲨烯异构体被鉴定为对紫外线A高度敏感的皮肤表面脂质分解产物，可能作为体外和体内光氧化应激的标志物。
