Cai Bao-Xiang, Jin Song-Liang, Luo Dan, Lin Xiang-Fei, Gao Jie
Department of Dermatology, First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China.
Biol Pharm Bull. 2009 May;32(5):837-41. doi: 10.1248/bpb.32.837.
Ultraviolet (UV)-induced DNA damage is a crucial molecular trigger for sunburn cell formation and skin cancer. Nucleotide excision repair (NER) is the main mechanism in repairing UVB-induced DNA damage to mammalian cells. The purpose of this study was to investigate the functional role of ginsenoside Rb1 in UV-induced DNA damage and apoptosis in HaCaT (keratinocyte cell line) cells, and Xpc(-) knockout mouse keratinocytes. Flow cytometry and Hoechst 33258 staining were performed in analyzing UV-induced apoptosis in keratinocytes treated with ginsenoside Rb1. The ImmunoDotBlot assay was used to detect cyclobutane pyrimidine dimers, the main sign of DNA damage. Western blot analysis was applied for analyzing Xeroderma pigmentosum-C (XPC) and excision repair cross-complementing 1 (ERCC1), two of the NER proteins. Ginsenoside Rb1 inhibited UV-induced apoptosis of keratinocytes and caused a notable reduction in UV-specific DNA lesions which was due to induction of DNA repair. This reduction was not observed in Xpc(-) knockout keratinocytes. Ginsenoside Rb1 induced the expression of specific components of the NER complex, such as XPC and ERCC1. Our results demonstrate that ginsenoside Rb1 can protect cells from apoptosis induced by UV radiation by inducing DNA repair.
紫外线（UV）诱导的DNA损伤是晒伤细胞形成和皮肤癌的关键分子触发因素。核苷酸切除修复（NER）是修复UVB诱导的哺乳动物细胞DNA损伤的主要机制。本研究的目的是探讨人参皂苷Rb1在UV诱导的HaCaT（角质形成细胞系）细胞和Xpc（-）基因敲除小鼠角质形成细胞的DNA损伤和凋亡中的功能作用。在用人参皂苷Rb1处理的角质形成细胞中，采用流式细胞术和Hoechst 33258染色分析UV诱导的凋亡。使用免疫斑点印迹法检测DNA损伤的主要标志——环丁烷嘧啶二聚体。采用蛋白质免疫印迹分析来分析两种NER蛋白——着色性干皮病C（XPC）和切除修复交叉互补蛋白1（ERCC1）。人参皂苷Rb1抑制UV诱导的角质形成细胞凋亡，并使UV特异性DNA损伤显著减少，这是由于诱导了DNA修复。在Xpc（-）基因敲除的角质形成细胞中未观察到这种减少。人参皂苷Rb1诱导NER复合物特定成分如XPC和ERCC1的表达。我们的结果表明，人参皂苷Rb1可通过诱导DNA修复来保护细胞免受UV辐射诱导的凋亡。
