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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。
OBJECTIVE: Endonuclease III may play an important role in DNA repair repair system, and whether it can effectively promote DNA damage repair is discussed in this paper. Methods: In this study, DNA damage was analyzed by “comet” electrophoresis. The DNA damage was induced by human lymphocytes and Hela cells with DNA damage induced by 100 μmol H 2 O 2, reaching 198 5 and 32 0 (AU, respectively) Two groups of cells were divided into two groups: one group was control group, the other group was supplemented with 25μl (1μg / ml) of endonuclease Ⅲ in the experimental group.After 30min, 60min, 180min and 240min Observation of DNA damage at break. RESULTS: The DNA fragmentation of lymphocytes was gradually restored in the control group after 4 h of incubation. The DNA damage decreased from 198 5 at the initial stage to 6 4 2 7 (AU). The experimental group supplemented with endonuclease III, 4h after repair, but the DNA damage damage rate is still significantly higher than the control group (P <0.05). Hela cells showed high sensitivity to H 2 O 2 and strong self-repair ability. DNA damage in control group decreased from 32 0 at the initial stage to 19 (AU) after 4 h, and the self-repair rate reached 94.1% However, the DNA damage rate of Hela cells supplemented with endonuclease Ⅲ was significantly higher than that of the control group at 30min, 60min, 180min and 240min (P <0.05). CONCLUSIONS: This result suggests that endonuclease III increases the rate of DNA damage during DNA damage repair.