中文摘要：

目的观察60Coγ射线照射后食管癌细胞周期、细胞凋亡及其相关蛋白表达的变化，为食管癌放射治疗、靶向治疗提供理论依据。方法食管癌细胞株TE-13进行不同剂量（0、1、2、5、10、15Gy）照射后，应用流式细胞术分别检测照射后1、2、12、24和48h细胞周期和凋亡指数的变化；同时采用Westernblot方法检测MDC1和53BP1蛋白表达情况。结果TE-13细胞照射后12、24、48h，TE-13细胞的G，／01期、G2／M期和S期的变化呈现明显剂量依赖性，1Gy和2Gy照射后12h，细胞G2／M期阻滞开始出现；5、10、15Gy照射后24h，细胞G2／M期阻滞最为明显，与对照组（0Gy组）相比，差异具有统计学意义（P〈0．05）；15Gy照射后12h、24、48h，TE-13细胞的凋亡增加非常显著（P〈0．01）；不同剂量照射后1、2、24h，TE-13细胞MDC1和53BP1蛋白表达未见明显变化（P〉0．05）。结论TE-13细胞经不同剂量放射线照射后，细胞周期出现明显的G2／M期阻滞，细胞凋亡指教明显增加，但对MDC1和53BP1蛋白表达未见明显影响。

英文摘要：

Objective To investigate changes of cell cycle, apoptosis and protein expression in esophageal carcinoma cells after 60Co y-rays irradiation, it is the basis as combing target treatment and radiotherapy for esophageal cancer. Methods Using flow cytometry （FCM） to check the percentage of different phase cells and apoptosis at 1, 2, 12, 24, 48 h after irradiation （0,1,2,5, 10,15Gy）. Expression of MDC1 and 53BP1 were detected by Western blot after irradiation. Results The percentage of G0/G1, G2/M and S phase of TE-13 cells was changed dependence on doses increasing of irradiation. At 12 h after irradiation with 1 Gy and 2 Gy, arrest of G2/M stage was gradually increased and reached the peak at 24 h after irra diation with 5,10,15 Gy （P〈0. 05）. Apoptotic index of TE-13 cell was obviously elevated at 12 h,24 h and 48 h after irradiation with 15 Gy （P〈0. 01）. However, expression of MDC1 and 53BP1 proteins in TE-13 cells were no significant changes at 48 h after irradiation with 5,10,15 Gy （P〈0. 05）, compared with the control group. Conclusion G2/M arrest and apoptosis of TE-13 cells were remarkable increasing after different doses irradiation. Meanwhile, No changes of expression of MDC1 and 53BP1 proteins in TE-13 cells were investigated after irradiation.