中文摘要：

目的建立应激性溃疡细胞损伤模型，观察过氧化氢对人胃腺癌细胞株AGS的浓度及时间损伤效应，并探讨miRNA-146a对其调控作用。方法（1）将人胃腺癌细胞株AGS分为5组，每组4孔：其中4组在200μmol／L过氧化氢处理3、6、12、24 h，另1组为未处理组，分别检测人胃腺癌细胞株AGS脂质过氧化代谢产物丙二醛含量和超氧化物歧化酶（ SOD ）活力。（2）将人胃腺癌细胞株AGS分为6组，每组4孔，其中4组分别用50、100、200、400、600μmol／L过氧化氢处理6 h，另1组为未处理组，检测其丙二醛含量和SOD活力。（3）将人胃腺癌细胞株AGS分为2组，实验组和对照组，每组4孔，对照组不做处理，实验组用200μmol／L过氧化氢刺激6 h后，采用实时定量PCR法分别检测两组细胞miRNANA-146a的相对表达量。（4）将人胃腺癌细胞株AGS分为4组，每组4孔：未处理组、miRNANA对照组、miRNA-146a抑制组、miRNA-146a增强组。处理组分别转染miRNA-146a对照剂、miRNA-146a抑制剂和miRNA-146a模拟物，培养24 h后，用200μmol／L过氧化氢刺激6 h，检测细胞miRNA-146a表达、丙二醛含量和SOD活力。多组间比较采用单因素方差分析，两组间比较采用LSD-t检验。结果（1）在200μmol／L过氧化氢刺激后，未处理组、不同时间培养组组间细胞丙二醛含量、SOD活力比较，差异均有统计学意义（F＝46．744、42．736，P值均小于0．01）；随着作用时间的延长，细胞丙二醛含量逐渐升高，在培养6 h时达到峰值（2．15±0．50）μmol／mg，然后逐渐降低；随着作用时间的延长，SOD活力逐渐降低，在培养6 h时达到最低（6．51±0．54） U／mg，然后逐渐升高。（2）用不同浓度的过氧化氢处理人胃腺癌细胞株AGS 6 h后，未处理组、不同浓度处理组组间细胞丙二醛含量、SOD活力比较，差异均有统计学意义（F＝152．786、129．231，P值均小于0．01）；随

英文摘要：

Objective To observe the concentration and time damage resulting from hydrogen peroxide on human gastric cancer cell line AGS and to investigate the effect regulated from microRNA -146a by constructing the cell model of stress ulcer .Methods (1) The AGS cells were divided into 5 groups, with 4 wells in each group.The content of malondialdehyde and the vigor of superoxide dismutase ( SOD) were tested which were kind of lipid peroxidation products from AGS cells that stimulus with 200 μmol/L hydrogen peroxide concentration at time points of 3, 6, 12 and 24 h.(2) The AGS cells were divided into 6 groups, with 4 wells in each group .Then the content of malondialdehyde and the vigor of SOD were tested which were kind of lipid peroxidation products from AGS cells that stimulus with 50, 100, 200, 400 and 600μmol/L hydrogen peroxide concentration all after 6 hours.(3) The AGS cells were divided into 2 groups, with 4 wells in each group.Then the AGS cells were excited 6 hours with 200 μmol/L hydrogen peroxide applying real-time PCR to detect gene expression of miRNA-146a of AGS cells.(4) The AGS cells were divided into 4 groups, with 4 wells in each group.Cells in miRNA-146a control group were transfected with microRNA control; cells in miRNA-146a enhancement group were transfected with miRNA-146a mimics; cells in miRNA-146a inhibition group were transfected with miRNA-146a inhibitor.After cultivating for 24 hours, miRNA-146a expression, the content of malondialdehyde and the vigor of SOD of the cells wer tested that have been stimulated 6 hours by hydrogen peroxide .Statistics were chose one-factor analysis of variance between groups and LSD-t test for the two groups .Results ( 1 ) After 200 μmol/L hydrogen peroxide stimulation , comparing the malondialdehyde content and SOD vitality in cells between untreated group and different time training group, the differences were statistically significant ( F=46.744, 42.736, P values were less than 0.01).As the extension of the time, the malondialdehyde content of cells was g