Garmyn M, Roelandts R
Photodermatology Unit, University of Leuven, Belgium.
J Invest Dermatol. 1992 Feb;98(2):187-90. doi: 10.1111/1523-1747.ep12555835.
The acute and chronic deleterious effects of UVA on skin have prompted a growing interest in developing effective UVA-photoprotective sunscreens. The quantification of their UVA photoprotection remains, however, a major problem. In the present study, murine skin edema induced by 8-methoxypsoralen plus UVA (PUVA) is evaluated as a screening method for quantifying the UVA photoprotection of commercially available sunscreens. The PUVA-induced murine skin edema is provoked on the dorsa of female hairless albino mice and measured with a hand-held micrometer. A clear time course and a well-defined dose-response relationship are demonstrated. Therefore, a UVA-photoprotection factor (UVA-PF) could be defined by dividing the minimal edema dose with sunscreen by the minimal edema dose without sunscreen. The UVA-PF values obtained with this method were quantitatively and qualitatively very similar to those obtained in 8-methoxypsoralen-photosensitized murine skin by using the number of sunburn cells as the biologic end point and were qualitatively similar to UVA-PF values obtained in human skin using phototoxic erythema and UVASUN-induced tanning as the parameter. It is concluded that PUVA-induced murine skin edema offers an objective, reproducible, and easily applicable screening method for quantifying the degree of UVA photoprotection of a sunscreen.
UVA对皮肤的急慢性有害影响促使人们对开发有效的UVA光防护防晒霜的兴趣日益浓厚。然而，对其UVA光防护效果进行量化仍然是一个主要问题。在本研究中，8-甲氧基补骨脂素加UVA（PUVA）诱导的小鼠皮肤水肿被评估为一种用于量化市售防晒霜UVA光防护效果的筛选方法。在雌性无毛白化小鼠的背部诱发PUVA诱导的小鼠皮肤水肿，并用手持测微计进行测量。结果显示出清晰的时间进程和明确的剂量反应关系。因此，UVA光防护因子（UVA-PF）可以通过将使用防晒霜时的最小水肿剂量除以不使用防晒霜时的最小水肿剂量来定义。用这种方法获得的UVA-PF值在数量和质量上与以晒伤细胞数量作为生物学终点在8-甲氧基补骨脂素光敏化的小鼠皮肤中获得的值非常相似，并且在质量上与以光毒性红斑和UVASUN诱导的晒黑作为参数在人体皮肤中获得的UVA-PF值相似。得出的结论是，PUVA诱导的小鼠皮肤水肿为量化防晒霜的UVA光防护程度提供了一种客观、可重复且易于应用的筛选方法。
