不同LET射线对SMMC-7721细胞辐射敏感性与周期的影响

Analysis of radiosensitivity and cell cycle of SMMC-7721 hepatoma cell line irradiated with different LET rays

目的研究不同LET射线对SMMC-7721肝癌细胞辐射敏感性、周期进程和凋亡的影响，为重离子治疗癌症的临床应用积累基础数据。方法以0、0．5、1、2、4和8Gy的^12C^6＋离子及X射线分别照射处于指数生长期的SMMC-7721细胞，用克隆形成率测定细胞辐射敏感性，通过流式细胞术测定细胞DNA含量以确定各时相细胞的比例及细胞凋亡情况。结果^12C^6＋离子所致的SMMC-7721细胞存活率明显低于x射线。随着吸收剂量的增加和修复时间的延长，^12C^6＋离子能导致更显著的细胞S期阻滞、G2/M期阻滞延迟和细胞凋亡。结论与X射线相比，^12C^6＋离子辐照能更有效地杀伤HepG2肝癌细胞，并诱导其凋亡。

Objective To study the effect of different LET rays on change of radiosensitivity, cell cycle and apoptosis in SMMC-7721 hepatoma ceils. Methods Exponentially grown SMMC-7721 cells were irradiated with ^12C^6＋ ions and X-ray at doses of 0, 0.5, 1, 2, 4 and 8 Gy. The radiosensitivity of cells was assessed by means of the colony-forming assay. The DNA content, percentage of each cell-cycle phase and the apoptosis rate were determined with flow cytometry analysis. Results The survival fraction of SMMC-7721 hepatoma cells was remarkably lower after irradiation with ^12C^6＋ ions than that of X-ray. With the increases of dose and repair time, the S phase arrest, G2/M phase arrest delay and the apoptosis in SMMC-7721 cells were significantly induced by ^12C^6＋ ions. Conclnsions ^12C^6＋ ions can kill the SMMC-7721 cells and induce apoptosis more effectively in the cells than X-rays.