Narbutt Joanna, Lesiak Aleksandra, Jochymski Cezary, Kozlowski Wojciech, Sysa-Jedrzejowska Anna, Norval Mary
Department of Dermatology, Medical University of Lodz, Lodz, Poland.
Exp Dermatol. 2007 Oct;16(10):837-43. doi: 10.1111/j.1600-0625.2007.00598.x.
The impact of repeated doses of solar simulated radiation (SSR) has not been evaluated, particularly to determine if photoadaptation and photoprotection develop over time. In this study, erythema, pigmentation, cyclooxygenase (COX)-1 and 2 expression and thymine dimer (dTT) formation were evaluated in the skin of irradiated subjects of phototype II or III. Groups of 7-10 volunteers were whole-body irradiated with a low dose of SSR on each of 10 consecutive days followed by a single erythemal ultraviolet B (UVB) dose on a small body area, or irradiated only with the single erythemal UVB dose on a small body area, or irradiated with the low dose of SSR on each of 30 consecutive days, or were unirradiated. Erythema and pigmentation were measured 24 h after the final SSR or UVB, and skin biopsies collected for the assessment of COX(+) cells and dTT(+) nuclei. The repeated SSR exposures induced a small increase in pigmentation without erythema, and were slightly protective against the erythemal effects of the subsequent high UVB dose. The number of COX-1(+) and 2(+) cells increased as a result of 10-days SSR and rose still further after 30-days SSR, indicating that photoadaptation had not developed. The SSR exposures did not result in any protection against the further increase in COX-1 and 2 expression caused by the erythemal UVB dose. In contrast, for dTT formation, the repeated SSR exposures led to a limited degree of both photoadaptation and photoprotection.
多次剂量的太阳模拟辐射（SSR）的影响尚未得到评估，尤其是未确定光适应和光保护是否会随时间发展。在本研究中，对II型或III型光皮肤类型的受辐照受试者的皮肤进行了红斑、色素沉着、环氧化酶（COX）-1和-2表达以及胸腺嘧啶二聚体（dTT）形成的评估。将7至10名志愿者分为几组，连续10天每天对其进行低剂量SSR全身照射，随后在小面积身体部位给予单次红斑量紫外线B（UVB）照射，或者仅在小面积身体部位给予单次红斑量UVB照射，或者连续30天每天给予低剂量SSR照射，或者不进行照射。在最后一次SSR或UVB照射后24小时测量红斑和色素沉着，并采集皮肤活检样本以评估COX（+）细胞和dTT（+）细胞核。多次SSR照射导致色素沉着略有增加但无红斑，并且对随后高剂量UVB的红斑效应有轻微保护作用。由于10天的SSR照射，COX-1（+）和-2（+）细胞数量增加，在30天的SSR照射后进一步增加，这表明光适应尚未形成。SSR照射并未对红斑量UVB照射引起的COX-1和-2表达进一步增加产生任何保护作用。相比之下，对于dTT形成，多次SSR照射导致了一定程度的光适应和光保护。
