补充核酸内切酶Ⅲ对DNA氧化损伤影响的研究  

THE EFFECT OF ENDONUCLEASE Ⅲ SUPPLEMENTATION ON THE DAMAGE OF DNA STRAND BREAKS

作　　者：杜卫[1] 刘四朝[2] 马爱国[1] 

机构地区：[1]青岛大学医学院医学营养学系,山东青岛266021 [2]中国农业科学院研究生院

出　　处：《癌变．畸变．突变》2000年第1期31-34,共4页Carcinogenesis,Teratogenesis & Mutagenesis

摘　　要：目的 :核酸内切酶Ⅲ在DNA损伤的切补修复体系中可能发挥着重要作用 ,是否有效地促进DNA损伤修复本文进行了探讨。方法 :本研究采用“彗星”电泳技术分析DNA断裂损伤 ,利用人体淋巴细胞和Hela细胞并用 10 0 μmolH2 O2 诱导DNA严重损伤 ,其损伤分别达到 198 5和 32 0 (专用单位 ,AU) ,然后再将两种细胞各分为两组 ;一组为对照组 ,另一组为实验组补充2 5 μl(1μg/ml)的核酸内切酶Ⅲ .在培养至 30min ,6 0min ,180min和 2 40min时观察DNA断裂损伤情况。 结果 :淋巴细胞DNA断裂损伤在对照组中经过 4h培养后逐渐得到修复 ,DNA损伤由初始时的 198 5下降到 6 4 2 7(AU) ;补充核酸内切酶Ⅲ的实验组尽管DNA断裂经过 4h后也得到修复 ,但DNA断裂损伤率仍明显高于对照组 (P均 <0 .0 5 )。Hela细胞对H2 O2 表现出较高的敏感性并有极强的自身修复能力 ,对照组DNA断裂损伤从初始时的 32 0下降到 4h后的 19(AU) ,自身修复率达到94 1% ,然而补充核酸内切酶Ⅲ的Hela细胞DNA断裂损伤率在 30min、6 0min、180min、2 40min时均明显高于对照组 (P <0 .0 5 )。结论 :本结果提示核酸内切酶Ⅲ在DNA损伤修复中增加了DNA的断裂损伤率。Purpose and Methods: The aim of the study was observing the effect of endonuclease Ⅲ supplementation on the damage of DNA strand breaks, which were measured by comet assay (SCGE). Results: DNA strand break damage of lymphocytes and Hela cells induced by 100μmol H\-2O\-2 in controls reached 198.5 and 320 arbitary units respectively. The rate of DNA strand breaks of lymphocytes was gradually decreased from the beginning to 4 hour culture in control group. At the end of 4 hour culture, there was a much lower rate of DNA repair in Endonuclease Ⅲ group with 33.4% than control group with 67.6% (P<0.05). The same result was found in HeLa cells. The levels of DNA strand breaks was quickly decreased from 320 to 19 arbitary units in control group within 4 hour culture, whereas the DNA strand breaks in supplementing group with Endonuclease Ⅲ was kept at a high level with 172.0 arbitary units at 4 hour culture (P<0.05). Conclusion: The study suggested that the supplementation of endonuclease Ⅲ could increase the levels of DNA strand breaks.

关 键 词：核酸内切酶Ⅲ 彗星电泳 DNA氧化损伤 DNA修复 

分 类 号：Q523[生物学—生物化学] Q343.245