不同中波紫外线照射对角质形成细胞干细胞因子／kit表达及黑素细胞迁移的影响

Effects of ultraviolet irradiation at different wavelengths on the expression of SCF/kit in keratinocytes and the migration of melanocytes

目的探讨不同中波紫外线照射对角质形成细胞干细胞因子／kit表达及黑素细胞迁移的影响。方法不同剂量的311nm窄谱中波紫外线（NB—UVB）及308nm单频准分子光（MEL）照射培养的HaCaT角质形成细胞株，ELISA方法测定培养上清液中干细胞因子含量，培养上清液作为条件化培养基培养A375黑素瘤细胞，RT—PCR测定A375细胞c—kitmRNA的表达，微孔滤膜法测定A375细胞迁移功能的变化。结果不同剂量的NB—UVB和MEL照射HaCaT细胞均可使干细胞因子分泌增加，其分泌量与照射剂量呈剂量依赖关系。用所收集的条件化培养基处理A375细胞，后者干细胞生长因子受体kit mRNA的表达显著上调，迁移功能亦显著增加。相同剂量的NB—UVB和MEL照射，对角质形成细胞干细胞因子／kit表达及黑素细胞迁移的影响无显著差异。结论NB—UVB和MEL两种波长紫外线照射均可通过同时上调角质形成细胞干细胞因子和黑素细胞kit的表达，增加黑素细胞的迁移。

Objective To investigate the effects of narrow band UVB （ NB-UVB ） and monochromatic excimer laser 308 nm （ MEL 308 nm ） on the expression of SCF/kit in keratinocytes and the migration of melanocytes. Methods HaCaT cells were irradiated with 311 nm NB-UVB and MEL 308 nm at various doses （ 100, 200, and 400 mJ/cm^2 ）. Cell culture supematants （ conditioned medium ） were harvested at 24 h post-irradiation, and analyzed by enzyme-linked immunosorbent assay （ELISA） for concentration of the c-kit ligand, stem cell factor （ SCF ）. The conditioned medium was examined for its ability to affect the expression of c-kit mRNA in A375 melanoma cells by reverse transcriptase-polymerase chain reaction （ RT-PCR ）, and the migration of A375 cells through the micropore filter. Results In both NB-UVB and MEL 308 nm groups, the concentrations of SCF in UVB-irradiated HaCaT conditioned medium were increasing in a UVB-dose dependent manner. The conditioned medium could significantly induce the expression of c-kit mRNA in A375 cells and significantly enhance the migration of A375 cells （ P 〈 0.01 ）. Nevertheless, there was no significant difference in the ability of conditioned medium to induce c-kit expression and enhance the melanocytes migration between the same dose of NB-UVB and MEL 308 nm. Conclusions The results indicate that both NB-UVB and MEL 308 nm can upregulate the expression of SCF in keratinocytes, the expression of kit in melanocytes, and the migration of melanocytes. These may partially account for the therapeutic mechanisms of NB-UVB and MEL 308 nm on vitiligo.