中文摘要：

目的 研究受照前后沉默H2AX基因对裸鼠移植瘤的影响，方法 将60只裸鼠按随机数字表法分为空白组、照射组、空载体组、空载体照射组、沉默（H2AX）组和沉默（H2AX）照射组,每组10只.于裸鼠皮下接种相应细胞,制备裸鼠模型，接种21 d后,给予6MVX射线15 Gy单次照射,受照后48 h每组处死5只裸鼠,将肿瘤标本按Western blot、RT-PCR及流式细胞分析要求处理,检测蛋白水平、RNA水平及细胞周期的改变，结果 沉默组肿瘤体积为（42.76±4.40） mm^3,明显小于空白组（73.18±8.80） mm^3和空载体组（71.27±8.40） mm^3（F=67.8,P＜0.01）.沉默组组织中H2AX蛋白表达（0.12±0.03）明显低于空白组（1.12±0.11）和空载体组（1.16±0.08,F=34.27,P＜0.01），沉默组RNA水平（0.85±0.31）明显低于空白组（1.86±0.26）和空载体组（1.82±0.24,F=39.45,P＜0.01），组织的免疫共沉淀显示,照射使γ-H2AX与MDC1、53BP1发生明显相互作用，沉默H2AX后,其相互作用减弱，受照后各组肿瘤体积在分组之间总体存在差异（F=13.56,P＜0.01），沉默照射组凋亡率为（24.15±2.25）％,较照射组（13.26±1.54）％和空载体照射组（12.78±1.47）％明显增高（F =54.33,P＜0.01）.照射后引起G2/M期阻滞,沉默照射组较照射组阻滞减轻（F=10.21,P＜0.01），结论 体内研究显示沉默H2AX基因可以提高食管癌放射敏感性、

英文摘要：

Objective To explore the effects of silencing H2AX gene on esophageal cancer ECA109 cell xenograft growth and sensitivity to radiotherapy in nude mice.Methods BALB/c nude mice models were established by subcutaneously inoculating differently treated ECA109 cells into nude mice.By random number table method 60 nude mice were divided into six groups,including blank group,irradiation group,negative group,negative with irradiation group,silence group and silence with irradiation group.The nude mice were irradiated with 15 Gy of 6 MV X-rays 21 d after inoculation.After irradiation 48 h,half of each mice group was terminated.The tumor specimens were processed by Western blot,RT-PCR and flow cytometry were used to detect the change in protein levels,RNA levels,and cell cycle.Results The tumor volume was （42.76 ±4.40） mm^3 in silence group,significantly smaller than that of the blank group （73.18±8.80） mm^3 and the negative group（71.27 ±8.40） mm^3（F=67.8,P〈0.01）.H2AX protein expression level in the silence group was also significantly lower （0.12 ±0.03 vs.1.12 ±0.11,1.16 ± 0.08,F =34.27,P 〈 0.01）.Relative H2AX mRNA expression level in the silence group was （0.85 ± 0.31）,significantly lower than that of the blank group （1.86 ± 0.26） and the negative group （1.82 ±0.24,F =39.45,P 〈 0.01）.Co-immunoprecipitation assay showed that γ-H2AX and MDC1,53BP1 obvious interaction after irradiation,which would be weakened through silencing H2AX.The tumor volumes at different groups had significant difference after irradiation （F =13.56,P 〈 0.01）.The apoptosis rate in the silence group was significantly higher than that of the blank group and the negative group [（24.15±2.25） % vs.（13.26±1.54） %,（12.78±1.47） % （F=54.33,P〈0.01）].G2/M phase arrested in the silence with irradiation group lower than that of the radiation group （F =10.21,P 〈 0.01）.Conclusions Silencing H2AX gene expression could inhibit the growth of esophageal cancer ECA109 cell xenograft and in