茶叶中表没食子儿茶素没食子酸酯抑制中波紫外线诱导HaCaT细胞氧化损伤研究

摘要

目的：研究茶叶中表没食子儿茶素没食子酸酯(EGCG)对中波紫外线(UVB)诱导的人表皮角质形成细胞(HaCaT)光损伤的保护作用。方法用不同浓度的EGCG对HaCaT细胞进行预处理6 h,采用60 mJ/cm2的剂量照射细胞,用MTT法检测细胞生存率,吸取细胞上清液检测超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH–Px)、乳酸脱氢酶(LDH)的活性和丙二醛(MDA)含量变化,用荧光法检测细胞内ROS含量。结果 UVB辐射对HaCaT细胞造成严重损伤,与对照组相比,细胞活性下降21.63%；与UVB辐射模型组相比, EGCG尤其高剂量可提高UVB照射后HaCaT细胞的存活率5.89%,显著提高SOD、GSH–Px活性(P<0.01),降低LDH活性(P<0.01),减少自由基ROS和MDA含量(P<0.01)。结论 EGCG可以减少UVB诱导HaCaT细胞的损伤和凋亡,具有光保护作用,其机制与增强细胞抗氧化能力和加速清除氧自由基有关。%ABSTRACT:Objective To study the photo-protective effect of epigallocatechin gallate in tea on HaCaT cells damaged from ultraviolet radiation B.Methods Sub–confluent HaCaT cells were incubated for 6 h with different doses of EGCG, and then irradiated with 60 mJ/cm2 doses of UVB. The cell viability was tested by MTT method. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), lactate dehydrogenase (LDH), and the level of malondialdehyde (MDA) of supernatant were detected with colorimetric methods. The content of ROS was measured with the fluorescence method.Results Compared with control group, the UVB irradiation could seriously damage HaCaT cell and gave rise to 21.63% cell viability decline. EGCG, especially this with the high dose, could enhance cell viability by 5.89%, increase SOD and GSH-Px activity in supernatant under UVB irradiation, and decrease LDH activity and the contents of MDA and ROS in dose–dependent manner (P<0.01).Conclusion EGCG can relieve UVB-induced oxidative damage and apoptosis of HaCaT cells, which may be the reasons that they enhance the oxidase activity and clear the oxy-radicals in cells.