模拟日光照射后皮肤CD1a、CD68阳性细胞变化的研究

目的 观察正常人皮肤经日光模拟器照射（solar-simulated ultraviolet radiation，ssUVR)后,朗格汉斯细胞（Langerhans cells, LC）和CD68阳性的巨噬细胞的变化。方法14名健康汉族女性志愿者于背部非曝光部位接受ssUVR照射。选择2个正方形部位，一处为正常对照，另一处为每日一次ssUVR照射。第4天照射后的72小时，进行活检取材。对所有标本进行CD1a和CD68免疫组化染色。结果 未照射部位正常表皮内的LC密度为258±61个/mm2，ssUVR照射部位的LC密度明显降低为96±53个/mm2，LC的形态不完整，树突变短而不明显。真皮浅层CD68阳性的巨噬细胞，未照射部位密度为290±22个/mm2，ssUVR照射部位的密度升高为399±65个/mm2。经过照射后真皮这些巨噬细胞数目明显增多位置上移，形态上树突变长并且大多数互相连接紧密。结论ssUVR照射可使LC数目减少，形态破损。真皮内的巨噬细胞则增高，这似有助于弥补紫外线照射对局部免疫的抑制作用。

Changes of density and morphology of CD1a- and CD68-positive cells in human skin after simulated solar radiation

Abstract] Objective To observe changes in CD1a+ Langerhans cells and CD68+ dermal macrophages in healthy adult human skin after irradiation with solar-simulated ultraviolet. Methods Fourteen healthy Han Chinese women were recruited in the study after obtaining informed consent. An area on the non-sun-exposed back skin of each subject was irradiated by 1.5x minimum erythema dose ( MED) of ssUVR once per day for four days. A biopsy was taken from each subject 72 hours after the last irradiation and frozen sections of the biopsies were stained by ABC immunohistochemistry for CD1a and CD68. Results After ssUVR irradiation there was a significant decrease in the number of LC to 96±53/mm2 compared to 258±61/mm2 in normal control skin 72 hours post-irradiation (P < 0.001). The staining showed irregular morphology of the CD1a+ LC with shortened dendrites. After ssUVR there was a significant increase in the number of CD68+ macrophages in the dermis to 399±65/mm2 compared to 290±22/mm2 in normal control skin 72 hours post-irradiation (P < 0.001). The location of these macrophages moved up toward the epidermis and the cells showed long and inter-connecting dendrites. Conclusions ssUVR could reduce LC density in the epidermis but the dermal macrophages increased in density 72 hours after ssUVR, indicating a compensatory or inflammatory mechanism that stimulate such increase in the dermis.