中文摘要：

目的观察60Co照射后体外培养的食管癌细胞株TE-13和ECA109细胞中MDC1和53BP1蛋白表达、ECA109细胞核内MDC1和53BP1斑点数量的变化,探讨放射线对食管癌细胞中相关蛋白表达的影响。方法 Western blot检测照射后细胞中MDC1和53BP1蛋白表达,激光共聚焦显微镜观察放射线照射后食管癌细胞ECA109中MDC1和53BP1细胞核内斑点数量的变化。结果 0、1、2、5、10Gy照射后1、2、24h,TE-13和ECA109细胞MDC1和53BP1蛋白表达未见明显变化（P〉0.05）;细胞接受不同剂量放射线照射后1h,MDC1和53BP1核内斑点的数量呈现明显剂量依赖性,与对照组（0Gy组）相比,差异具有统计学意义（P〈0.05）;同时发现4Gy放射线照射后30min（MDC1）～1h（53BP1）细胞核内斑点的数量最多,分别为26.3和36.7个,其后斑点的数量逐渐下降,与对照组（0Gy组）相比,差异均具有统计学意义（P〈0.05）。结论单纯放射线照射未发现食管癌细胞中MDC1和53BP1蛋白表达发生明显变化,但两种蛋白在细胞核内斑点的数量与剂量和照射后时间存在明显的量效关系。

英文摘要：

Objective To study the expression of mediator of the MDC1 and 53BP1 mediators in esophageal carcinoma cells after 60Co γ-rays irradiation in vitro.Methods Expression of MDC1 and 53BP1 proteins were detected by Western blot after different time points with 1,2,5,10 Gy in TE-13 and ECA109 esophageal carcinoma cells in vitro,ECA109 cell was collected 1h after different irradiation dosages（0,2,4,6,8 and 10 Gy） and different time points（5,15,30,60,120 and 240 min）after 4 Gy of γ-irradiation,the immunofluorescence images were taken under a Zeiss fluorescence microscope.Results The expression of MDC1 and 53BP1 proteins in TE-13 and ECA109 cells has no sig-nificant change at 1h,2h and 24 h after irradiation with 1,2,5,10Gy（P0.05）;MDC1 and 53BP1 foci were evident 5 min after exposure to 2Gy IR.The number of foci increased gradually with the increase of the IR dose（P0.05）.The time course of MDC1 and 53BP1 foci formatited and dispersed after exposure to 4Gy-IR had been investigated.MDC1 and 53BP1 foci were evident at the earliest time point examined,5 min after irradiation.The average number of foci per cell peaked at the 30 min（MDC1）and 1 h（53BP1）time point,the average number of foci were 26.3 and36.7 respectively.After that,the MDC1 and 53BP1 foci began to disperse,gradually,the number of foci per cell returned to baseline levels 4 h after irradiation.Compared with the control group,there have remarkable difference in the average number of foci of MDC1 and 53BP1（P0.05）.Conclusion Irradiation can affect the number of gene MDC1 and 53BP1 nuclear foci but not expression of MDC1 and 53BP1 protein in esophageal carcinoma cells.