中文摘要：

目的 探讨芦荟甙对中波紫外线（UVB）辐射HaCaT细胞诱导核因子kB（NF-kB）及诱导型一氧化氮合酶（iNOS）表达的抑制作用。方法 采用MTY法测定HaCaT细胞的增殖变化，生化比色法检测培养细胞上清液中NO含量，RT-PCR法检测HaCaT细胞诱导型一氧化氮合酶（iNOS）mRNA的表达变化，免疫荧光细胞化学染色测定NF-kBP65的激活表达。结果 30mJ／cm^2UVB辐射HaCaT细胞，细胞的增殖明显下降，NO的合成分泌增加，iNOS mRNA表达显著增加，同时NF-kB被激活，从细胞浆易位到细胞核。芦荟甙对HaCaT细胞的增殖有显著促进作用。用不同浓度芦荟甙预处理HaCaT细胞，可以显著抑制UVB辐射诱导的NF-kB激活，下调iNOS mRNA表达及NO合成分泌。经统计学分析，差异有统计学意义（P＜0．01）。结论 芦荟甙通过抑制UVB辐射诱导的NF-kBP65激活，下调iNOS mRNA表达，减少NO合成分泌，发挥防护紫外线辐射损伤的作用，在炎症性皮肤病防治中可能发挥重要作用。

英文摘要：

Objective To investigate the protective effect of aloin on inducible nitric oxide synthase （iNOS） and nuclear faetor kappa B （NF-kB） synthesis of HaCat cells induced by ultraviolet B （UVB） irradiation. Methods The proliferation of HaCat cells was measured by MTT method, iNOS mRNA was detected by reverse transcriptase polymerase chain reaction （RT-PCR）. NO production was assessed by spectrophotometric method, and expression of NF-kB P65 was measured by immunofluorescent staining. Results After irradiation with 30 mJ/cm^2 of UVB, proliferation of HaCat cells was decreased, and NO generation and iNOS mRNA synthesis in HaCat cells were increased. UVB irradiation could also activate the expression of NF-kB P65 and promote its translocation into nucleus. NO generation and iNOS mRNA synthesis were markedly down-regulated in a dose-dependent manner by pre-treatment with different concentrations of aloin. The activation of NF-kB P65 was inhibited while the proliferation of HaCat cells was increased. All the difference reached statistical significanee （P〈0.01 ）. Conclusions Our results confirm that aloin treatment could inhibit NF-kB P65 activation, and down-regulate iNOS mRNA expression and NO generation induced by UVB irradiation. Aloin might play an important role in the treatment of skin inflammatory diseases, especially ultraviolet irradiation injury.