Reeve V E, Boehm-Wilcox C, Bosnic M, Reilly W G
Department of Veterinary Pathology, University of Sydney, New South Wales, Australia.
J Invest Dermatol. 1994 Dec;103(6):801-6. doi: 10.1111/1523-1747.ep12413445.
A series of experimental sunscreen preparations based on a common vehicle, containing increasing concentrations of either octyl-N-dimethyl-p-aminobenzoate (o-PABA) or 2-ethylhexyl-p-methoxycinnamate (2-EHMC) as the ultraviolet B (UVB) absorber, has been tested in the hairless mouse for the ability to protect from erythema, from the systemically suppressive effects of UVB (280-320 nm) radiation on contact hypersensitivity, and from photoisomerization of epidermal urocanic acid. All the preparations protected efficiently from the edema component of the erythema response when mice were exposed to UVB radiation equivalent to three times the minimal erythema dose (MED). However, when mice were exposed to UVB radiation equivalent to 15 x MED, protection from erythema was observed only at the higher concentrations of each UVB absorber (10% 2-EHMC and 10% or 15% o-PABA). Protection from the UVB-induced suppression of contact hypersensitivity was shown to be dependent on both the nature of the UVB absorber and its concentration. Photoimmunoprotection by the sunscreens containing 2-EHMC was evident at lower concentrations (5% and 10% 2-EHMC) than with o-PABA, following both 3 x MED and 15 x MED of UVB exposure. Photoimmunoprotection by o-PABA-containing sunscreens was observed only at 15% o-PABA following 3 x MED, and failed at all tested concentrations after 15 x MED of UVB exposure. Regardless of the photoimmunoprotective capacity, sunscreen preparations containing either of the UVB absorbers prevented the UVB-induced formation of cis urocanic acid in the mouse epidermis and in vitro under all conditions tested. Thus, there appeared to be a correlation between protection from edema and from cis urocanic acid formation at 3 x MED of UVB, but a dissociation of these variables at 15 x MED of UVB. There was no relation apparent at either UVB dose between either edema or cis urocanic acid formation and protection from suppression of contact hypersensitivity.
一系列基于通用载体的实验性防晒制剂，含有浓度递增的N-二甲基对氨基苯甲酸辛酯（o-PABA）或2-乙基己基对甲氧基肉桂酸酯（2-EHMC）作为紫外线B（UVB）吸收剂，已在无毛小鼠中进行测试，以评估其预防红斑的能力、预防UVB（280 - 320纳米）辐射对接触性超敏反应的全身抑制作用的能力，以及预防表皮尿刊酸光异构化的能力。当小鼠暴露于相当于最小红斑剂量（MED）三倍的UVB辐射时，所有制剂都能有效预防红斑反应中的水肿成分。然而，当小鼠暴露于相当于15×MED的UVB辐射时，仅在每种UVB吸收剂的较高浓度（10% 2-EHMC和10%或15% o-PABA）下观察到对红斑的防护作用。结果表明，预防UVB诱导的接触性超敏反应抑制作用既取决于UVB吸收剂的性质，也取决于其浓度。在3×MED和15×MED的UVB照射后，含（5% 和10% 2-EHMC）的防晒霜的光免疫保护作用在较低浓度下比含o-PABA的防晒霜更明显。含o-PABA的防晒霜的光免疫保护作用仅在3×MED后15% o-PABA浓度下观察到，在15×MED的UVB照射后，所有测试浓度下均未观察到该作用。无论光免疫保护能力如何，含有任何一种UVB吸收剂的防晒制剂在所有测试条件下均能预防UVB诱导的小鼠表皮和体外顺式尿刊酸的形成。因此，在UVB 3×MED时，预防水肿和预防顺式尿刊酸形成之间似乎存在相关性，但在UVB 15×MED时，这些变量相互分离。在任何一种UVB剂量下，水肿或顺式尿刊酸形成与预防接触性超敏反应抑制之间均未发现明显关系。
