Alcalay J, Goldberg L H, Wolf J E, Kripke M L
Department of Dermatology, Baylor College of Medicine, Houston, Texas.
J Invest Dermatol. 1990 Aug;95(2):144-6. doi: 10.1111/1523-1747.ep12477895.
Exposure of human skin in vivo to UVB radiation induces pyrimidine dimers in DNA and alters the morphology and function of epidermal Langerhans cells. Cells in human skin have been reported to contain a photoreactivation repair mechanism that, following exposure to UVA or visible light, repairs UVB-induced pyrimidine dimers. The purpose of this study was to determine whether exposure to photoreactivating light would also reverse the UVB-induced morphologic alterations in human Langerhans cells. The skin of eight healthy volunteers was exposed to a low dose of UVB radiation (between 0.75 and 1.5 times the minimal erythema dose), and immediately thereafter exposed to photoreactivating light from either BLB fluorescent lamps (UVA radiation) or incandescent bulbs (visible light). After exposure to UVB radiation, the number of ATPase+ epidermal Langerhans cells was reduced in all subjects to between 21% and 65% of that in unirradiated skin, and the majority of the remaining cells exhibited morphologic alterations. Exposure of the UVB-irradiated skin to photoreactivating light did not reverse or reduce these effects. We conclude that UVB-induced morphologic alterations of human Langerhans cells are not subject to photoreactivation. These results imply either that pyrimidine dimers are not involved in these effects of UVB irradiation, or that photoreactivation does not occur in human Langerhans cells in situ.
人体皮肤在体内暴露于中波紫外线（UVB）辐射会诱导DNA中的嘧啶二聚体形成，并改变表皮朗格汉斯细胞的形态和功能。据报道，人体皮肤细胞含有一种光复活修复机制，在暴露于长波紫外线（UVA）或可见光后，可修复UVB诱导的嘧啶二聚体。本研究的目的是确定暴露于光复活光是否也能逆转UVB诱导的人类朗格汉斯细胞形态学改变。八名健康志愿者的皮肤暴露于低剂量的UVB辐射（最小红斑量的0.75至1.5倍之间），随后立即暴露于来自BLB荧光灯（UVA辐射）或白炽灯泡（可见光）的光复活光。暴露于UVB辐射后，所有受试者中ATP酶阳性的表皮朗格汉斯细胞数量减少至未照射皮肤中细胞数量的21%至65%之间，其余大多数细胞呈现形态学改变。将UVB照射过的皮肤暴露于光复活光并不能逆转或减轻这些影响。我们得出结论，UVB诱导的人类朗格汉斯细胞形态学改变不能通过光复活来恢复。这些结果表明，要么嘧啶二聚体不参与UVB辐射的这些效应，要么光复活在人体原位朗格汉斯细胞中不会发生。
