Corcuff P, Leveque J L
L'oreal Research Laboratories, Aulnay-Sous-Bois, France.
Photodermatol. 1988 Jun;5(3):110-5.
The effects of UV irradiation on the human stratum corneum (SC) were studied under both artificial and natural conditions. Artificial UV exposure was performed with a solar simulator. Single doses of radiation from 1 to 3 MED were delivered on the backs of volunteers and the measurements were recorded for a period of one month. Corneocytes were harvested from the skin surface by using a "turbine-machine". Their count and projected area were measured by image analysis. The evolution of corneocyte counts showed 3 steps: 1) a background level of desquamation until the 8th day; 2) a sharp increase from day 9 to day 11; and 3) a plateau until the 20th day. No evolution of the corneocyte size occurred at 1 MED, but a decrease was recorded at day 20 for 2 MED and earlier for 3 MED. Natural sun exposure was investigated in 2 different experiments: on a population living in a sunny coastline and on professional racing cyclists. In these natural conditions, the response of the SC to UV led to an increase in corneocyte count associated with a decreased size. Even though natural environment involves both weather and sun influences, results showed similar SC responses. In case of acute irradiation, the skin recovers its initial state one month later, but in the natural environment, it maintains altered features as long as the UV irradiation occurs.
在人工和自然条件下研究了紫外线照射对人体角质层（SC）的影响。使用太阳模拟器进行人工紫外线照射。向志愿者背部给予1至3个最小红斑量（MED）的单剂量辐射，并记录为期一个月的测量结果。使用“涡轮机”从皮肤表面采集角质形成细胞。通过图像分析测量其数量和投影面积。角质形成细胞数量的变化呈现三个阶段：1）直到第8天的背景脱屑水平；2）从第9天到第11天急剧增加；3）直到第20天趋于平稳。在1个MED时角质形成细胞大小没有变化，但在2个MED时第20天记录到减小，在3个MED时更早出现减小。在两个不同的实验中研究了自然阳光照射：一个是针对生活在阳光充足海岸线上的人群，另一个是针对职业自行车赛车手。在这些自然条件下，角质层对紫外线的反应导致角质形成细胞数量增加且大小减小。尽管自然环境涉及天气和阳光的影响，但结果显示角质层有相似的反应。在急性照射的情况下，皮肤一个月后恢复到初始状态，但在自然环境中，只要紫外线照射持续，皮肤就会保持改变后的特征。
