Eberlein-König B, Placzek M, Przybilla B
Dermatologische Klinik und Poliklinik der Ludwig-Maximilians-Universität München, Munich, Germany.
J Am Acad Dermatol. 1998 Jan;38(1):45-8. doi: 10.1016/s0190-9622(98)70537-7.
UV radiation causes acute adverse effects like sunburn, photosensitivity reactions, or immunologic suppression, as well as long-term sequelae like photoaging or malignant skin tumors. UV radiation induces tissues to produce reactive oxygen species, eicosanoids and cytokines. Inhibition of these mediators might reduce skin damage. Antioxidants such as ascorbic acid and d-alpha-tocopherol have been found to be photoprotective in some in vitro studies and animal experiments.
Our purpose was to assess the protective effect of systemic vitamins C and E against sunburn in human beings.
In a double-blind placebo-controlled study, each of 10 subjects took daily either 2 gm of ascorbic acid (vitamin C) combined with 1000 IU of d-alpha-tocopherol (vitamin E) or placebo. The sunburn reaction before and after 8 days of treatment was assessed by determination of the threshold UV dose for eliciting sunburn (minimal erythema dose [MED]) and by measuring the cutaneous blood flow of skin irradiated with incremental UV doses against that of nonirradiated skin.
The median MED of those taking vitamins increased from 80 to 96.5 mJ/cm2 (p < 0.01), whereas it declined from 80 to 68.5 mJ/cm2 in the placebo group. Cutaneous blood flow changed significantly (p < 0.05) for most irradiation doses with decreases in those given vitamins and increases in the placebo group.
Combined vitamins C and E reduce the sunburn reaction, which might indicate a consequent reduced risk for later sequelae of UV-induced skin damage. The increase of sunburn reactivity in the placebo group could be related to "priming" by the previous UV exposure.
紫外线辐射会导致晒伤、光过敏反应或免疫抑制等急性不良反应，以及光老化或恶性皮肤肿瘤等长期后遗症。紫外线辐射会诱导组织产生活性氧、类花生酸和细胞因子。抑制这些介质可能会减少皮肤损伤。在一些体外研究和动物实验中，已发现抗氧化剂如抗坏血酸和d-α-生育酚具有光保护作用。
我们的目的是评估系统性维生素C和E对人类晒伤的保护作用。
在一项双盲安慰剂对照研究中，10名受试者每人每天服用2克抗坏血酸（维生素C）与1000国际单位d-α-生育酚（维生素E）的组合或安慰剂。通过测定引起晒伤的阈值紫外线剂量（最小红斑剂量[MED]）以及测量不同递增紫外线剂量照射皮肤与未照射皮肤的皮肤血流量，来评估治疗8天前后的晒伤反应。
服用维生素者的MED中位数从80增加到96.5 mJ/cm²（p < 0.01），而安慰剂组的MED中位数从80下降到68.5 mJ/cm²。对于大多数照射剂量，皮肤血流量有显著变化（p < 0.05），服用维生素者的血流量减少，而安慰剂组增加。
维生素C和E联合使用可减轻晒伤反应，这可能表明紫外线诱导的皮肤损伤后期后遗症的风险相应降低。安慰剂组晒伤反应性的增加可能与先前紫外线暴露的“激发”有关。
