中文摘要：

目的：探讨熊果酸（ursolic acid,UA）对H2O2诱导的人脐静脉内皮细胞（HUVECs）氧化应激的保护及相关分子机制。方法：培养人脐静脉内皮细胞,分组为正常组,H2O2组（400μmol/L,作用8h）、1μmol/L熊果酸预给药组、5μmol/L熊果酸预给药组、10μmol/L熊果酸预给药组、15μmol/L熊果酸预给药组和阳性对照组（0.1g/L Vit E＋H2O2）。采用CCK-8检测各组内皮细胞的活性,DCFH-DA荧光探针法检测ROS含量,硝酸还原酶法检测细胞培养上清液中NO含量及细胞内NOS的表达,Western blotting检测有效剂量组内皮细胞Pten、Akt、p-Akt（ser473）、eNOS的蛋白表达水平。结果：H2O2处理后,细胞存活率较正常组明显下降,NO、NOS含量降低,ROS水平升高;熊果酸给药后,其中三组细胞存活率明显升高,NO和NOS的水平明显升高。细胞内ROS含量降低,Pten蛋白水平表达降低,Akt磷酸化水平增加,eNOS表达水平升高。结论：熊果酸预给药能明显改善HUVECs的细胞活性,可能与促进内皮细胞NO的释放和熊果酸潜在的清除ROS而直接抗氧化的作用有关,其机制可能涉及到Pten的下调和Pi3k/Akt信号通路的激活。

英文摘要：

Objective： To investigate the protective effect of ursolic acid（ UA） on oxidative damage induced by H2O2 in human umbilical vein endothelial cells（ HUVECs） and its possible mechanism. Methods： HUVECs were cultured in vitro and divided into seven groups： control group,model group（ cells incubated by 400μmol / L H2O2 for 8h）,others were added H2O2 after UA with different concentrations respectively（ 1μmol/L UA,5μmol/L UA,10μmol/L UA,15μmol/L UA） and positive drug（ 0. 1g/L Vit E） worked for 12 h. The cell vitality（ OD value）was measured by cell counting kit-8. Reactive oxygen species（ ROS） were detected by the dichlorodihydrofluorescein（ DCF） assay. The NO concentration in the cell medium and activity of NOS of HUVECs were detected by using nitric acid deoxidize enzyme method. The proteins expression of PTEN,Akt,phospho-Akt（ ser473） and eNOS in HUVECs were detected by Western Blot. Results： H2O2 decrease the cells＇ survival（ 50. 30 2. 88） %,reduce the level of NO and NOS and increase the content of ROS,compared with control group. UA groups with higher concentration increased the cell viability to（ 55. 65 2. 73） %,（ 64. 78 5. 21） %,（ 74. 56 4. 04） %（ P ﹤ 0. 05）,which fits with the positive control group（ 67. 84 3. 79） %. The production activity of NO and NOS were increased and the intracellular ROS level was reduced. Finally,UA can effectively downregulate pten and increase the expressions of eNOS,phospho-Akt. Conclusion： Ursolic acid exerted protective effects against H2O2 induced injury in endothelial cells,including inceased NO and eNOS level and reduced the ROS damage,which may act through the downregulation of Pten and the activation of Pi3 k / Akt signaling pathway.