羟自由基、γ射线和重离子束致死效应的比较

Comparison of Lethal Effects between Hydroxyl Radicals, γ-Rays and Heavy-Ion Beam

以集落法测存活率、用双链断裂模型分析实验数据 ,比较研究了羟自由基、γ射线和 12 5 .5keV μm碳离子束对B16细胞和V79细胞的致死效应。结果表明 :三种处理对细胞都有明显的致死作用 ,剂量越大 ,效果越明显 ;重离子束的致死效应比γ射线强 ,而且对抗常规辐射的黑色素瘤也有效 ,证明了重离子治癌的优势 ;羟自由基与DNA的作用没有一次击中的成分 ,碳离子束则以一次击中为主 ,γ射线介于两者之间 ;两种细胞对羟自由基的敏感性与对电离辐射的敏感不同 。

Clone forming method and DNA double strand break model were employed to study the lethal effects of B16 and V79 cells treated with hydroxyl radicals,γ rays or 125.5?keV/μm 12 C 6+ . The results show that all the treatments have significant lethal effects on both kinds of cells.It is confirmed that heavy ion irradiation has advantages on cancer therapy because heavy ion beam have heavier lethal effects than γ rays and can efficiently kill melanoma cells that resist to general radiations. Single hit does not exist in the process of hydroxyl radicals reaction with DNA molecules,but plays a major role in the process of heavy ion irradiation,while both single and double hits exist in the process of radiation with γ rays. The radiosensitivity of the two kinds of cells to ionizing radiation is not consistent to the sensitiviy to hydroxyl radicals,which implies that the indirect action of ionizing radiation can not be simply considered as that of free radicals.