申请人:Slominski Andrzej
公开号:US20070218023A1
公开(公告)日:2007-09-20
Melatonin, which can be produced in the skin, exerts a protective effect against damage induced by ultraviolet radiation (UVR). The present study investigated the effect of UVB, the most damaging component of UVR, on melatonin metabolism in HaCaT keratinocytes and in a cell-free system. Four metabolites were identified by HPLC and LC-MS: 6-hydroxymelatonin, AFMK, 2-hydroxymelatonin (the main intermediate between melatonin and AFMK) and 4-hydroxymelatonin. Concentrations of these photoproducts were directly proportional to UVR-dose and to melatonin substrate content, and their accumulation was time dependent. The UVR-dependent increase of AFMK and 2-hydroxymelatonin was also detected in keratinocytes, where it was accompanied by simultaneous consumption of intracellular melatonin. Of note, melatonin and its two major metabolites, 2-hydroxymelatonin and AFMK, were also detected in untreated keratinocytes, neither irradiated nor preincubated with melatonin. Thus, intracellular melatonin metabolism is enhanced under exposure to UVR. The additional biological activity of these individual melatonin metabolites increases the spectrum of potential actions of the recently identified cutaneous melatoninergic system.
褪黑激素可以在皮肤中产生,对紫外辐射(UVR)引起的损伤具有保护作用。本研究调查了UVB对HaCaT角质细胞和无细胞系统中褪黑激素代谢的影响,UVB是UVR中最具破坏性的组分。通过HPLC和LC-MS鉴定了四种代谢产物:6-羟基褪黑激素、AFMK、2-羟基褪黑激素(褪黑激素和AFMK之间的主要中间体)和4-羟基褪黑激素。这些光产物的浓度与UVR剂量和褪黑激素底物含量成正比,它们的积累是时间依赖的。在角质细胞中也检测到AFMK和2-羟基褪黑激素的UVR依赖性增加,同时伴随着细胞内褪黑激素的消耗。值得注意的是,未经辐照或未预先孵育褪黑激素的角质细胞中也检测到褪黑激素及其两种主要代谢产物2-羟基褪黑激素和AFMK。因此,在UVR暴露下,细胞内褪黑激素代谢得到增强。这些单个褪黑激素代谢产物的额外生物活性扩大了最近发现的皮肤褪黑激素系统的潜在作用范围。