Moshell A N, Bjornson L
J Invest Dermatol. 1977 Mar;68(3):157-60. doi: 10.1111/1523-1747.ep12492479.
Erythropoietic protoporphyria is a genetic disease caused by the accumulation of protoporphyrin IX. This molecule absorbs 400-nm light and its presence is at times associated with severe cutaneous photosensitivity. The only effective treatment for this disease is oral administration of beta carotene. Several possible mechanisms of photoprotection by beta carotene were investigated using the photohemolysis of red blood cells as an in vitro model. Additional studies were done in an in vivo model which involves lethal hematoporphyrin photosensitization of white mice. The photoprotective effects of beta carotene were compared with those of alpha tocopherol, an agent which possesses some but not all the properties that have been implicated in explaining the known effectiveness of beta carotene. In the photohemolysis model, both compounds demonstrated partial protection. In hematoporphyrin-photosensitized mice, tocopherol showed some protection at high doses, while beta carotene showed greater protection at lower concentrations. Although these results suggest that photoprotective was due to free radical scavenging or singlet oxygen quenching, properties common to both agents, they do not rule out the possible role of 400-nm light absorption, a property of beta carotene alone.
红细胞生成性原卟啉病是一种由原卟啉IX积累引起的遗传性疾病。该分子吸收400纳米的光，其存在有时与严重的皮肤光敏性有关。这种疾病唯一有效的治疗方法是口服β-胡萝卜素。使用红细胞的光溶血作为体外模型，研究了β-胡萝卜素的几种可能的光保护机制。在体内模型中进行了额外的研究，该模型涉及对白色小鼠进行致命的血卟啉光敏化。将β-胡萝卜素的光保护作用与α-生育酚的光保护作用进行了比较，α-生育酚具有一些但不是所有与解释β-胡萝卜素已知有效性相关的特性。在光溶血模型中，两种化合物都表现出部分保护作用。在血卟啉光敏化的小鼠中，生育酚在高剂量时显示出一定的保护作用，而β-胡萝卜素在较低浓度时显示出更大的保护作用。尽管这些结果表明光保护作用是由于自由基清除或单线态氧猝灭，这是两种物质共有的特性，但它们并不排除β-胡萝卜素单独具有的400纳米光吸收可能发挥的作用。
