中文摘要：

目的：观察人参皂苷Rb1对中波紫外线诱导的人原代角质形成细胞光损伤的影响，探讨其可能的作用机制。方法：通过细胞培养法，加入不同浓度人参皂苷Rb1（5、20、50μg／ml）预处理细胞，以中波紫外线辐射剂量30ml／cm^2诱导细胞DNA损伤，MTT法观察细胞活力的变化，Hoechst 33258染色观察细胞凋亡，免疫细胞化学染色观察细胞DNA损伤环丁烷嘧啶二聚体。结果：人参皂苷Rb1对未辐射中波紫外线的角质形成细胞的活力无明显影响，但可显著增强紫外线辐射后细胞的活力，减少核浓缩、核小体的形成及细胞凋亡的发生，加速环丁烷嘧啶二聚体的清除。结论：人参皂苷Rb1可能通过加速DNA损伤的清除，抑制紫外线诱导的角质形成细胞凋亡的发生。

英文摘要：

Objective To observe the photo-damage of primary keratinocyte induced by ultraviolet B （UVB）radiation treated with various doses of ginsenoside Rbl, and investigate its possible mechanisms in vitro. Methods MTT assay was performed to analyze cell viability after UVB radiation of 30 ml/cm^2. The damage of nucleolus and cyclobutane pyrimidine dimmer triggered by UVB were scanned by Hoechst 33258 staining and immunocytochemistry. Results Ginsenoside Rbl showed no influence on cell viability of keratinocyte without UVB radiation. But when radiated by UVB, cell viability of keratinocyte pretreated with ginsenoside Rbl was enhanced greatly. It was found that the cell survival rate decreased gradually and the damage of nucleolus aggravated at the radiation dose of 30 ml/cm^2. At the dose of 50 μg/ml, obvious protective effect of ginsenoside Rbl against UVB radiation-induced keratinocyte growth inhibition and nucleolus damage can be observed. Conclusion UVB radiation inhibits human keratinocytes growth and ginsenoside Rbl can relief the apoptosis by accelerating the clearance of DNA damage.