An H T, Yoo J Y, Lee M K, Shin M H, Rhie G E, Seo J Y, Chung J H, Eun H C, Cho K H
Department of Dermatology, Seoul National University College of Medicine, and Laboratory for Cutaneous Aging Research, Clinical Research Institute, Seoul National University Hospital, Chongno-Gu, Seoul, Korea.
Photodermatol Photoimmunol Photomed. 2001 Dec;17(6):266-71. doi: 10.1034/j.1600-0781.2001.170604.x.
To establish whether the effect of fractionating radiation modifies the effects of ultraviolet (UV) radiation on epidermal melanocytes, we compared the clinical and histological effects of single high dose radiation against repeated intermediate to low dose radiation on epidermal melanocytes.
Three minimal erythema UV doses (MED) were administered to three sites on the buttocks of healthy volunteers. One site was irradiated with 0.5 MED UV every day for 6 consecutive days, another site was irradiated with 1 MED UV every second day, and a third site received a single dose of radiation with 3 MED UV. The treatment was replicated on the other buttock. For the evaluation of UV-induced erythema and pigmentation, erythema and melanin indices were measured at 2 and 14 days post-irradiation. For purposes of histological evaluation, tissue specimens taken from each irradiated site at 2 and 14 days post-irradiation and were stained with monoclonal antibodies against Mel-5, HMB-45 and tyrosinase. Fontana-Masson silver staining, DOPA staining and split DOPA reactions were also performed.
At 14 days post-irradiation, UV radiation induced melanocyte activation, proliferation and melanogenesis in proportion to the radiation dose administered to each fraction. The most prominent responses were observed after single high doses of radiation.
When the total administered dose is identical, fractionation of radiation dose diminishes the effects of UV radiation on epidermal melanocytes. Furthermore, long, uninterrupted doses of UV radiation were found to more effective in inducing melanogenesis and melanocyte activation.
为确定分次照射辐射的效果是否会改变紫外线（UV）辐射对表皮黑素细胞的影响，我们比较了单次高剂量辐射与重复中低剂量辐射对表皮黑素细胞的临床和组织学影响。
对健康志愿者臀部的三个部位给予三个最小红斑量紫外线（MED）。一个部位连续6天每天接受0.5 MED紫外线照射，另一个部位每隔一天接受1 MED紫外线照射，第三个部位接受单次3 MED紫外线辐射。在另一侧臀部重复该治疗。为评估紫外线诱导的红斑和色素沉着，在照射后2天和14天测量红斑和黑色素指数。为进行组织学评估，在照射后2天和14天从每个照射部位采集组织标本，并用抗Mel-5、HMB-45和酪氨酸酶的单克隆抗体染色。还进行了Fontana-Masson银染色、多巴染色和分裂多巴反应。
照射后14天，紫外线辐射诱导黑素细胞活化、增殖和黑素生成，其程度与给予每个分次的辐射剂量成比例。单次高剂量辐射后观察到最显著的反应。
当总给药剂量相同时，辐射剂量的分次给药会减弱紫外线辐射对表皮黑素细胞的影响。此外，发现长时间、不间断的紫外线辐射剂量在诱导黑素生成和黑素细胞活化方面更有效。
