重离子辐射哺乳动物细胞敏感性的分子机理

A Possible Molecular Mechanism of Radiosensitivity in Mammalian Cells Exposed to Heavy Ions

研究了用传能线密度125.5keV/μm的12C6+辐照小鼠黑色素瘤、中国仓鼠肺、人的宫颈癌、人的肝癌细胞的敏感性以及DNA双链断裂和DNA双链断裂片段分布,结果表明细胞敏感性与DNA双链断裂之间没有一致的关系,提出了细胞辐射敏感性的一种可能的分子机理,即DNA序列敏感性位点协同DNA双链断裂互补性机理.由此解释了4种细胞系的不同敏感性问题.

Four types of cells, melanoma B16, cervical squamous carcinima HeLa, Chinese hamster V79 and hepatoma SMMC7721, were irradiated by 125.5 keV/μm carbon ions. Celullar sensitivities to irradiation indicated by D50 , DNA double strand break (DSB) and distribution of DSB fragments expressed by molecular weight are studied. The results show that there is not a consistent relationship between cellular sensitivity and DNA DSB induction, a possible molecular mechanism of radiosensitivity which is defined as 'a complementary mechanism of DNA sequence sensitive sites in cooperation with DNA DSB induction' is proposed. It gives a possible explanation of different sensitivity in four types of cell lines.