12C和X射线辐照人肺癌细胞H1299的生物学效应

用高传能线密度（LET）的12C离子束和低LET的X射线辐照体外培养的非小细胞肺癌H1299(p53基因缺失)， 研究它们的辐照生物学效应的差异。 用克隆形成率法测定了细胞对射线的辐射敏感性； 用AnnexinV/PI试剂盒检测了细胞早期凋亡； 用流式细胞仪检测了细胞周期变化。 实验结果表明， 12C离子束辐照H1299细胞的存活率明显低于用X射线辐照的； 12C离子束引起H1299细胞的早期凋亡率明显高于X射线辐照引起的， 且持续时间更长； 12C离子束引起的H1299细胞G2/M期的抑制更明显。 说明H1299细胞对高LET的12C离子束的辐射敏感性高于对X射线的， 重离子对p53基因缺失型肿瘤的治疗可实施较低的照射剂量、 较少的照射次数和较长的时间间隔。

Biological Effects of H1299 Cells Exposed to 12C Ion Beam and X-rays

To provide basic data for heavy ion cancer therapy， the biological effects of ionizing radiations with different linear energy transfers (LET) on radiosensitivity， cell cycle alteration and cell early apoptosis in H1299 cells were studied. The cell radiosensitivity was assessed by means of the standard colony forming assay. The experimental results show that the survival fraction of H1299 cells irradiated with the 12C ions is evidently lower than that in the case of the X rays. Moreover， compared with the X rays the G2/M phase arrest and delay degree and the early apoptosis percentage in H1299 cells irradiated with the 12C ions were more prominent with increasing the radiation dose and repairing time. These results suggested that H1299 cells were more sensitive to 12C ion beam than X rays. Moreover, less dose， few fractionation and longer fractionation interval were applicable to heavy ion therapy for p53 null type tumors.