目的：研究了竹叶总黄酮对紫外线B（UVB）诱发 HaCaT角质细胞氧化损伤的保护效果和机制。方法 HaCaT细胞经竹叶总黄酮预处理24 h后，以辐射剂量为20 mJ／cm2的 UVB照射细胞2 h后，MTT法测定细胞生存率。同时测定细胞内活性氧（ROS）水准，脂质过氧化程度，抗氧化酶（超氧化物歧化酶，SOD；过氧化氢酶，CAT和过氧化物歧化酶，GSH-Px）并利用RT-PCR法分析其 mRNA转录水准。ELISA法分析TNF-α和 IL-6分泌量。结果竹叶总黄酮可有效地抑制 UVB导致的细胞氧化损伤并提高其细胞生存率。与对照组相比，竹叶总黄酮还能有效降低受损细胞内 ROS水准，脂质过氧化程度，并提高 SOD、CAT和 GSH-Px等3种内源性抗氧化酶的活性及其它们的 mRNA转录水平。此外，竹叶总黄酮还能抑制 UVB所造成受损细胞分泌TNF-α和 IL-6炎性细胞因子的能力。结论竹叶总黄酮可通过降低细胞内 ROS水平，抑制细胞脂质过氧化，调节细胞内氧化酶的活性抑制 UVB导致的 HaCaT细胞氧化损伤。此外，竹叶总黄酮还可降低 UVB所诱发的 TNF-α和 IL-6分泌。%OBJECTIVE To investigate the protective effects of total flavonoids from bamboo (Phyllostachys pubescens) leaves (BLE) on UVB-irradiated oxidative damage in HaCaT keratinocytes.METHODS The HaCaT cells were pretreated with BLE for 24 h and then exposed to UVB(20 mJ/cm2) for 2 h.Cell viability was determined by MTT assay.The levels of reactive oxygen species (ROS),lipid peroxidation and antioxidant enzymes including catalase (CAT),superoxide dismutase (SOD) and glutathione peroxidase(GSH-Px) were measured.mRNA transcription levels of these antioxidant enzymes were determined by RT-PCR assay.In addition,the production of TNF-αand IL-6 were detected by ELISA assay.RESULTS BLE significantly reduced the UVB-induced HaCaT cell damage and improved the cell survival rates (P<0.05).Compared to the control group,BLE decreased the levels of ROS and lipid peroxidation,and increased the activities and mRNA transcription levels of endogenous antioxidant enzymes(SOD,CAT and GSH-Px)in UVB-irradiated HaCaT cells.In addition,BLE also in-hibited the secretion of TNF-αand IL-6 in UVB-irradiated HaCaT cells.CONCLUSION BLE can exhibit cytoprotective activi-ties against UVB-induced oxidative damage in HaCaT cells through the reduction of ROS,inhibition of lipid peroxidation and regulation of antioxidant enzymes activities.In addition,BLE can also decrease the levels of TNF-αand IL-6 in UVB-irradiated HaCaT cells.
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