中文摘要：

目的探讨单频308 nm准分子光对角质形成细胞的凋亡、细胞周期和干细胞因子表达的影响。方法采用MTT法确定最适能量密度，用流式细胞仪检测单频308nm准分子光对角质形成细胞的凋亡和细胞周期的影响。RT-PCR和蛋白质印迹分别检测单频308nm准分子光对角质形成细胞干细胞因子基因转录和蛋白表达水平的影响。结果用400mJ／cm^2单频308nm准分子光照射角质形成细胞后24h和48h，细胞凋亡明显增加（P〈0.05），48h时S期细胞虽有增加，但无统计学意义（P=0．059）。干细胞因子mRNA和蛋白表达均增加，在照射后12h左右达高峰。且蛋白表达随着照射剂量的增加而增加，但mRNA的表达未随剂量的增加而改变。结论单频308nm准分子光可导致角质形成细胞凋亡，促进干细胞因子的表达，这可能是准分子光治疗白癜风的机制之一。

英文摘要：

Objective To investigate the effect of 308 nm monochromatic excimer light on the apoptosis, cell cycle and stem cell factor （ SCF ） expression of human keratinocytes. Methods MTT was used to determine the optimal dose of the excimer light on the keratinocytes, and flow cytometry to examine the apoptosis and cell cycle of keratinocytes. The mRNA and protein expression of SCF was detected by RT-PCR and Western blot, respectively. Results The apoptosis rate of keratinocytes was significantly increased at 24 h and 48 h after the radiation with 308 nm monochromatic excimer light of 400 mJ/cm^2 （ both P 〈 0.05 ）. The cell count at S stage was elevated 48 h after the radiation, but no statistical difference was found for the elevation. Both the mRNA and protein expression of SCF increased after the radiation, and peaked at 12 h. The excimer light up-regulated the protein expression, but not mRNA expression of SCF, in a dose dependant manner. Conclusions The 308 nm excimer light could induce the apoptosis, and promote the expression of SCF mRNA and protein expression of keratinocytes, which might be a therapeutic mechanism of 308 nm excimer light in vitiligo.