快中子及混合射线照射后细胞周期再分布研究

Analysis of cell-cycle redistribution induced by exposure to cobalt-60 γ-ray,fast neutron or mixed beams

探讨应用流式细胞技术 (FCM )检测经6 0 Coγ射线、快中子照射和两者混合射线照射后的艾氏腹水癌细胞周期再分布的变化。方法 将艾氏腹水癌细胞接种在小鼠皮下 7d后 ,分别采用单一快中子射线DT2 0 0cGy ,单一6 0 Coγ射线DT6 5 0cGy ,混合射线快中子 10 0cGy + 6 0 Coγ射线32 5cGy照射肿瘤部位。在照射后不同时间 ,将各组小鼠处死取瘤体 ,进行FCM分析。 结果 单一6 0Coγ射线照射后主要表现为G2 期阻滞。在 2 4h的直方图中观察到S期丢失现象。快中子表现为对细胞的直接杀伤和G1 期阻滞 ;混合射线对细胞周期的影响表现了快中子和6 0 Coγ射线照射的双重特点。结论 应用混合射线得到了与单一快中子照射相同效应。提示应用混合射线治癌将是提高肿瘤局部控制率 ,减少晚期损伤的有效治疗方式。

Objective To study the features of cell cycle redistribution of Erhich Ascites Cells (EAC) following 60 Coγ-ray fast neutron or mixed beam irradiation with flow cytometry assay.Methods The mouse tumor,7 days after EAC subcutaneous transplant,received 60 Coγ-ray 6.5 Gy, fast neutron 2.0 Gy or mixed beam (γ.3.25 Gy + n.1.00 Gy )exposures,respectively, Then a series of Flow Cytometry (FCM) assays were conducted at different intervals after irradiation.Results For the 60 Coγ-ray efficiency,the main features of G 2 arrest and absence of S phase were shown in the 24 h histogram. For fast neutron,there were G 2 arrest also and a significant abnormal peak behind G 1, explained as the direct killing effect on EAC. And for mixed beams,these dual features were obtained.Conclusions Similar biologic effects are observed in both fast neutron or mixed beam exposures. In our opinion, the better local tumor control and less normal tissure impairment are to be expected with mixed beam radiotherapy.