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辐射及活性氧对DNA的损伤以及芥子碱的保护作用

李卫业, 李群, 郭房庆, 顾瑞琦

中科院上海植物生理研究所.上海 200032

摘要

在X射线照射下,小牛胸腺DNA的碱基损伤及链断裂随着剂量升高而增加,其损伤主要集中于链断裂;活性氧可以引起DNA损伤,H_(2)O_(2)仅造成少量伤害,当在含有H_(2)O_(2)的体系中加入微量的Cu~(2+)、Fe~(2+)时损伤急剧增加,这是由反应产生的·OH所致,Cu~(2+)的致损伤效果明显高于Fe~(2+)。·OH清除剂芥子碱具有很强的抗辐射及抗氧化作用,且对DNA无伤害。

关键词： 辐射; 活性氧; 芥子碱; DNA; 损伤; 保护

DNA damage induced by X-irradiation and reactive oxygen species and the protection against it by sinapine

Li Weiye, Li Qun, Guo Fangqing, Gu Ruiqi

Shanghai Institute of Plant Physiology,The Chinese Academy of Sciences.Shanghai 200032

Abstract

Base damage and strand break of calf thymus DNA (ctDNA) were detected and quantified by ~(32)P-postlabeling assay. Both of them increased with the dose of X-ray; and the percentage of strand break increased more sharply than base modification. DMSO(1 mol/L) drastically decreased the percentage of strand break but had very little effect against this base damage. This suggests that the strand break caused by X-irradiation resulted from ·OH produced in an indirect reaction, while the bases were damaged by electron transfer via direct reactin or by hydrogen or aquo electron via indirect reaction. Sinapine, which has no damage to ctDNA, can protect DNA against base damage and strand scissions of X-ray. In the ·OH producing system, the effect of damage-inducing of Cu~(2+) is greater than that of Fe~(2+). Sinapine also decrease the damage induced by ·OH. This result indicates that sinapine is also a strong antioxidant.

Key words: Radiation;Reactive oxygen;Species sinapine;DNA;Damage;Protectin

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引用本文：

李卫业, 李群, 郭房庆, 顾瑞琦. 辐射及活性氧对DNA的损伤以及芥子碱的保护作用[J]. 生理学报 1997; 49 (4): .

Li Weiye, Li Qun, Guo Fangqing, Gu Ruiqi. DNA damage induced by X-irradiation and reactive oxygen species and the protection against it by sinapine. Acta Physiol Sin 1997; 49 (4): (in Chinese with English abstract).