中文摘要：

目的：比较观察氧化应激状态下正常人表皮黑素细胞（MCs）与白癜风非皮损区MCs细胞膜表达CD40,CD80,HLA-DR和ICAM免疫分子水平的变化。方法：自5例健康成年包皮和5例稳定期白癜风下腹部非皮损区分别建立正常人表皮MCs和白癜风MCs的原代培养;将培养第2-3代细胞分别用100 mmol/L过氧化氢（H2O2）作用1 h或1.5 J/cm2长波紫外线（UVA）照射进行氧化应激处理;用二氯荧光素标记法测定两种MCs在H2O2处理和UVA照射前后胞内活性氧基（ROS）水平变化;用流式细胞仪分析CD40,CD80,HLA-DR和ICAM 4种免疫分子表达水平变化;用分光光度计法测定两种MCs过氧化氢酶活性。结果：过氧化氢酶活性测定结果显示白癜风MCs过氧化氢酶活性较正常人表皮MC明显减低（P〈0.01）。细胞内ROS水平测定发现H2O2处理和UVA照射均导致白癜风非皮损区MCs细胞内ROS水平急剧增高,与正常人MCs比较ROS的荧光强度有显著统计学差异（P〈0.01）。流式细胞仪检测结果表明除HLA-DR外,UVA照射可诱导白癜风非皮损区MCs高表达CD40,CD80和ICAM1,与未照射组白癜风MCs和UVA照射组正常人MCs比较均有显著统计学差异（P〈0.01）。结论：白癜风非皮损区MCs的抗氧化能力明显减低。UVA照射能上调白癜风MCs胞膜异位表达CD40,CD80和ICAM1免疫分子,提示在氧化应激状态下白癜风MCs可兼有增强的抗原呈递细胞样功能。

英文摘要：

Objective： To analyze the changes in ectopic expressions of immunological markers on cultured human melanocytes from healthy subjects and stable vitiligo patients in the presence or absence of oxidative stress.Methods： Cultured human melanocytes were isolated from the foreskins of five healthy subjects and the uninvolved abdominal skins of five stable vitiligo patients.The cells at the second to third passages were subsequently exposed to 100 mmol/L H2O2 for 1 h or 1.5 J/cm2 UVA radiation.The levels of intracellular reactive oxygen species（ROS） in both untreated and treated melanocytes were monitored by 2,7-dichlorofluorescin diacetate labeling.Flow cytometry was used to examine the expressions of immune marker proteins（CD40,CD80,HLA-DR,and ICAM1） on cellular surfaces.Catalase activities of both melanocytes were also measured with a spectrophotometery method.Results： Decreased catalase activities were found in vitiligo melanocytes to compare with normal melanocytes.The intercellular ROS levels in vitiligo melanocytes were abruptly increased upon exposure to UVA irradiation or H2O2 treatment.There was a significantly statistic difference of ROS level between normal and vitiligo melanocytes under conditions of oxidative stress（P0.01）.Flow cytometry data showed that CD40,CD80,and ICAM1,except for HLA-DR,were highly expressed by UVA-treated vitiligo melanocytes,but not by UVA-treated normal melanocytes and untreated vitiligo melanocytes.Conclusion： Vitiligo melanocytes possess a decreased antioxidative capacity.Ectopic expressions of CD40,CD80,and ICAM1 on cellular membranes of vitiligo melanocytes are enhanced while exposure to UVA irradiation.These findings provide evidence that melanocytes are also able to function as non-professional antigen presenting cells,especially under conditions of oxidative stress.