Yuen K S, Halliday G M
Department of Medicine (Dermatology), University of Sydney, New South Wales, Australia.
Photochem Photobiol. 1997 Mar;65(3):587-92. doi: 10.1111/j.1751-1097.1997.tb08610.x.
We investigated the involvement of epidermal lipid peroxidation in the induction of ultraviolet radiation (UVR)-induced suppression of the skin immune system. The shaved dorsal skin of C3H/HeJ mice was irradiated with one of two subinflammatory solar-simulated UVR protocols 3 days per week for 4 weeks. Then half of 1 mg, 1, 2.5 or 5 mg alpha-tocopherol in a vehicle of acetone was topically applied to the shaved dorsal skin before UVR, A 5 mg dose of vitamin E gave complete protection against a UVR protocol that induced a 55% reduction in the contact hypersensitivity response to 2,4,6-trinitrochlorobenzene and a 23% reduction in epidermal Langerhans cell density. Lower doses were ineffective. alpha-Tocopherol was unable to protect against a higher UVR protocol. As 5 mg alpha-tocopherol did not prevent postirradiation inflammatory edema it is unlikely that the antioxidant acted as a sunscreen. However, 5 mg alpha-tocopherol inhibited UVR-induced epidermal lipid peroxidation, suggesting that this may be one mechanism by which alpha-tocopherol prevented UVR-induced local immunosuppression. Scavenging of UVR-generated lipid peroxides and reactive oxygen may have inhibited loss of cell membrane integrity preventing depletion of LC numbers, thus protecting from local immunosuppression.
我们研究了表皮脂质过氧化在紫外线辐射（UVR）诱导的皮肤免疫系统抑制中的作用。将C3H/HeJ小鼠背部剃毛后的皮肤，按照两种亚炎症性模拟阳光UVR方案之一，每周照射3天，共照射4周。然后，在UVR照射前，将1毫克、1毫克、2.5毫克或5毫克α-生育酚溶解在丙酮载体中，局部涂抹于剃毛后的背部皮肤上。5毫克剂量的维生素E能完全保护小鼠免受UVR方案的影响，该方案会使对2,4,6-三硝基氯苯的接触性超敏反应降低55%，使表皮朗格汉斯细胞密度降低23%。较低剂量则无效。α-生育酚无法保护小鼠免受更高剂量UVR方案的影响。由于5毫克α-生育酚不能预防照射后的炎性水肿，因此这种抗氧化剂不太可能起到防晒作用。然而，5毫克α-生育酚可抑制UVR诱导的表皮脂质过氧化，这表明这可能是α-生育酚预防UVR诱导的局部免疫抑制的一种机制。清除UVR产生的脂质过氧化物和活性氧可能抑制了细胞膜完整性的丧失，从而防止朗格汉斯细胞数量减少，进而预防局部免疫抑制。
