80MeV/u20Ne10+离子对SMMC-7721细胞DNA损伤及细胞周期的影响

从辐照剂量和修复时间两个角度研究了重离子辐照对肿瘤细胞DNA损伤及细胞周期的影响，为重离子治癌的临床应用积累基础数据。不同剂量的80MeV／u^20Ne^10 辐照SMMC—7721细胞样品，利用单细胞凝胶电泳技术(Single Cell Gel Electrophoresis，SCGE)对细胞DNA损伤进行了检测，利用流式细胞技术(Flow Cytometry Methods，FCM)对细胞周期变化进行了分析。80MeV／u^20Ne^10 辐照后4小时内，SMMC—7721细胞的DNA损伤与辐照剂量呈线性关系，在0小时组其线性相关因子r为0．9621，4小时组为0．914；随着修复时间的增加，DNA损伤与辐照剂量不再线性相关，但0．5Gy，1Gy和2Gy三个剂量点的DNA损伤程度极为相近。另外，重离子辐照后SMMC—7721细胞发生S期和G2／M期阻滞现象，其随剂量变化及时间变化的规律不同于X、γ等低LET(Linear Energy Transfer)射线辐照。

Effect of 80MeV/u 20Ne10+ Ions on DNA Damage and Cell Cycle of SMMC-7721 Cells

In this paper, DNA damage and alteration of cell cycle in tumor cells irradiated by heavy ion with different doses at different repaired time were studied to building up the base data for clinical therapy. The human hepatoma cells chosen as the test cell line were irradiated by 80MeV/u20Ne10+; then their DNA damage and changes of cell cycle were detected by single cell gel electrophoresis (SCGE) and analyzed by flow cytometry methods (FCM) respectively. The DNA damage of SMMC7721 cells irradiated by 80MeV/u20Ne10+ varies with doses linearly at two time points of 0h and 4h. The linear correlative factors(r) of tail length with dose are 0.9621 at 0h and 0.9331 at 4h. Then the damages do not change with dose and there may be a threshold at 4Gy. Secondly, it was found that the percentage of cells in S phase and G2/M phase increased after irradiated by heavy ions. But their regulations corresponding to irradiation doses and repairing time do not be similar to those irradiated by X or γ rays or otherswith low LET.