十两茶提取物抗氧化型低密度脂蛋白诱导的内皮细胞衰老机制研究

Effect of Shiliang tea extracts on ox-LDL-induced senescence in endothelial cells and underlying mechanism

目的：探讨十两茶提取物对氧化型低密度脂蛋白（ox-LDL）诱导衰老细胞模型的影响及其可能的机制。方法将人脐静脉内皮细胞（HUVECs）株于含有10%牛血清的DMEM培养液中培养，使用ox-LDL孵育建立衰老细胞模型，用β？半乳糖苷酶染色法评价内皮细胞的衰老状态，分别予以不同剂量十两茶提取物及辛伐他汀预处理，检测培养液中活性氧（ROS）、非对称二甲基精氨酸（ADMA）、二甲基精氨酸二甲胺水解酶（DDAH）以及端粒酶活性水平。结果 ox-LDL诱导的内皮细胞衰老模型中β？半乳糖苷酶染色阳性的细胞数量显著增加，细胞内ROS水平、ADMA水平增强，DDAH和端粒酶活性降低，而十两茶提取物预处理可明显抑制这一过程（P＜0.05）。结论十两茶提取物在ox-LDL诱导的内皮细胞衰老进程中起抑制作用，其机制可能与降低细胞内ROS、ADMA水平以及提高DDAH水平和端粒酶活性有关。

Objective To determine the effect of the extract of Shiliang tea （a traditional tea from Anhua county, Hunan Province, China） on the senescence cells induced by oxidized low density lipoprotein （ox-LDL） and investigate the underlying potential mechanism. Methods Human umbilical vein endothelial cells （HUVECs） were cultured in the DMEM containing 10%bovine serum, and then treated with ox-LDL to establish the model of senescent cells.β-galactose glucoside enzyme staining was used to evaluate the senescence of the endothelial cells. Simvastatin （10μmol/L, positive control） and different doses of the extract of Shiliang tea （1.0,2.5 and 5.0g/L） were used to treat the cells before ox-LDL inducement. The levels of reactive oxygen species （ROS） and asymmetric dimethylarginine （ADMA）, and the activities of dimethylarginine dimethylaminohydrolase （DDAH） and telomerase in culture medium were detected. Results In the senescence model of the endothelial cells induced by ox-LDL, the amount of positive cells ofβ-galactose glucoside enzyme staining was significantly increased, the levels of ROS and ADMA were enhanced, and the activities of DDAH and telomerase were reduced. However, the pretreatment of the extract of Shiliang tea restrained the process apparently （P〈0.05）. Conclusion The extract of Shiliang tea plays a restraining role in the senescence process of endothelial cells induced by ox-LDL, which might be through reducing the levels of ROS and ADMA and improving the activities of DDAH and telomerase.