Barolet Daniel, Boucher Annie
RoseLab, Skin Optics Laboratory, Montreal, Quebec, Canada.
Lasers Surg Med. 2008 Feb;40(2):106-12. doi: 10.1002/lsm.20615.
As photoprotection with traditional sunscreen presents some limitations, the use of non-traditional treatments to increase skin resistance to ultraviolet (UV) induced damage would prove particularly appealing. The purpose of this pilot study was to test the potential of non-thermal pulsed light-emitting diode (LED) treatments (660 nm) prior to UV exposure in the induction of a state of cellular resistance against UV-induced erythema.
STUDY DESIGN/MATERIALS AND METHODS: Thirteen healthy subjects and two patients with polymorphous light eruption (PLE) were exposed to 5, 6, or 10 LED treatments (660 nm) on an EXPERIMENTAL anterior thigh region. Individual baseline minimal erythema doses (MED) were then determined. UV radiation was thereafter performed on the LED EXPERIMENTAL and CONTROL anterior thigh areas. Finally, 24 hours post-UV irradiation, LED pre-treated MED responses were compared to the non-treated sites.
Reduction of erythema was considered significant when erythema was reduced by >50% on the LED-treated side as opposed to CONTROL side. A significant LED treatment reduction in UV-B induced erythema reaction was observed in at least one occasion in 85% of subjects, including patients suffering from PLE. Moreover, there was evidence of a dose-related pattern in results. Finally, a sun protection factor SPF-15-like effect and a reduction in post-inflammatory hyperpigmentation were observed on the LED pre-treated side.
Results suggest that LED based therapy prior to UV exposure provided significant protection against UV-B induced erythema. The induction of cellular resistance to UV insults may possibly be explained by the induction of a state a natural resistance to the skin via specific cell signaling pathways and without the drawbacks and limitations of traditional sunscreens. These results represent an encouraging step towards expanding the potential applications of LED therapy and could be useful in the treatment of patients with anomalous reactions to sunlight.
由于传统防晒霜的光保护作用存在一些局限性，采用非传统疗法来增强皮肤对紫外线（UV）诱导损伤的抵抗力将极具吸引力。本初步研究的目的是测试在紫外线暴露之前，非热脉冲发光二极管（LED）治疗（660纳米）诱导细胞抵抗紫外线诱导红斑状态的潜力。
研究设计/材料与方法：13名健康受试者和2名多形性日光疹（PLE）患者的实验性大腿前侧区域接受5次、6次或10次LED治疗（660纳米）。然后确定个体基线最小红斑剂量（MED）。此后，对LED治疗的实验性大腿前侧区域和对照区域进行紫外线辐射。最后，在紫外线照射后24小时，将LED预处理的MED反应与未治疗部位进行比较。
当LED治疗侧的红斑相对于对照侧减少>50%时，红斑减少被认为具有显著性。在至少一次实验中，85%的受试者（包括患有PLE的患者）观察到LED治疗显著降低了UV-B诱导的红斑反应。此外，结果存在剂量相关模式的证据。最后，在LED预处理侧观察到类似防晒系数SPF-15的效果以及炎症后色素沉着的减轻。
结果表明，紫外线暴露前基于LED的疗法对UV-B诱导的红斑提供了显著保护。细胞对紫外线损伤的抗性诱导可能是通过特定细胞信号通路诱导皮肤产生自然抗性状态来解释的，且没有传统防晒霜的缺点和局限性。这些结果朝着扩大LED疗法的潜在应用迈出了令人鼓舞的一步，可能有助于治疗对阳光有异常反应的患者。
