^12C^6＋离子辐照诱发人类肝L02细胞hprt基因突变的研究

hprt mutation in human hepatocyte L02 cells induced by (12)~C^(6+) ions

本文研究12C6+离子辐照人类肝细胞系L02细胞诱发hprt基因突变与剂量的效应关系,为正确评价重离子对人体正常组织细胞的辐射风险及危害提供基础数据和依据。分别用12C6+离子束(LET为30keV/μm)和X射线(LET为0.2keV/μm)对L02细胞进行0～6Gy照射后,用克隆形成法检测细胞的存活分数,另外在含有6-TG的培养基中克隆、筛选hprt突变细胞株,测定突变频率。结果表明:12C6+离子辐照后L02细胞的存活分数明显小于X射线照后。两种射线照射后,每106个存活细胞中突变克隆的个数随照射剂量增大而增大,受照细胞的突变频率也都在1Gy处最大。但相对于X射线,人类肝细胞系L02细胞对高LET重离子辐射更敏感,而且12C6+离子束诱发更多的存活细胞hprt基因突变。

The work was to study hprt mutation inducted in human hepatocyte L02 cells exposed to ^12C^6＋ ions, and to provide basic data and evidence for risk assessment of heavy ion irradiation to healthy tissues. Human hepatocyte L02 cells were irradiated with 83.6 MeV/u ^12C^6＋ions with LET of 30 keV/μm or X-rays. Survival fractions of the cells were studied by colony-formation efficiency. Mutation induction at the hprt locus was detected by measuring 6-thioguanine-resistant clones. After 10 days of incubation in presence of 15 mg/L 6-TG7 the mutants were counted. The results showed that the survival fraction of L02 cells irradiated by carbon beams was much lower than that of the X-ray irradiated cells. The number of mutants per 10^6 surviving cells and the mutation frequency increased with the carbon ion and X-ray dose up to 1 Gy. It is concluded that human hepatocyte L02 cells are more sensitive to high-LET carbon ions, which are more effective in inducing hprt mutation in the survivors of L02 cells.