Bangha E, Elsner P, Kistler G S
Department of Dermatology, University of Zurich, Switzerland.
Dermatology. 1997;195(3):248-52. doi: 10.1159/000245953.
In a previous study, we reported a significant and dose-dependent suppression of UV-induced erythema in human skin by a topically applied melatonin preparation.
The present double-blind randomized study was designed to examine the influence of the application time point of topical melatonin on this antierythema effect.
Defined small areas on the lower back of 20 volunteers were treated with 0.6 mg/cm2 melatonin dissolved in a nanocolloid gel carrier either 15 min before or 1, 30 or 240 min after UV irradiation with twice the individual minimal erythema dose delivered by a Multiport Solar UV Simulator (UVA and UVB). The erythemata induced were evaluated by visual scoring and chromametry 24 h after irradiation.
Treatment of the skin with melatonin 15 min before UV irradiation proved to almost completely suppress the development of an UV-induced erythema. In contrast, no significant protective effects of melatonin were observed when it was applied after UV irradiation.
Topically applied melatonin has a clear-cut protective effect against UV-induced erythema. Free radical scavenging of UV-generated hydroxyl radicals and interference with the arachidonic acid metabolism are possible mechanisms of the melatonin action.
在之前的一项研究中，我们报道了局部应用褪黑素制剂对人体皮肤紫外线诱导的红斑有显著且剂量依赖性的抑制作用。
本双盲随机研究旨在探讨局部应用褪黑素的时间点对这种抗红斑效应的影响。
20名志愿者下背部的特定小区域，在用多端口太阳能紫外线模拟器（UVA和UVB）给予个体最小红斑量两倍的紫外线照射前15分钟，或照射后1、30或240分钟，用溶解于纳米胶体凝胶载体中的0.6mg/cm²褪黑素进行处理。照射24小时后，通过视觉评分和色度测定法评估诱导产生的红斑。
紫外线照射前15分钟用褪黑素处理皮肤，几乎完全抑制了紫外线诱导红斑的发展。相比之下，紫外线照射后应用褪黑素未观察到显著的保护作用。
局部应用褪黑素对紫外线诱导的红斑有明确的保护作用。清除紫外线产生的羟基自由基以及干扰花生四烯酸代谢可能是褪黑素发挥作用的机制。
