DNA解旋荧光分析法及其在细胞DNA辐射损伤和修复研究中的应用

FLUOROMETRIC ANALYSIS OF DNA UNWINDING METHOD AND ITS APPLICATION IN THE STUDIES OF DNA DAMAGE AND ITS REPAIR

本文改进和建立了能用于分析分裂和不分裂细胞DNA链断裂损伤的DNA解旋荧光分析法。对其中某些影响因素也作了一定的探讨。并观察了氧对辐射诱发哺乳动物细胞DNA链断裂损伤及重接修复的影响。结果表明:细胞DNA链断裂损伤程度与剂量呈线性关系。小鼠腹水型淋巴性白血病L_(7712)细胞的氧增强比值为3.0。3T3细胞的氧增强比随照射条件不同为1.01和1.37。乏氧条件受照的3T3细胞在有氧条件下37℃保温,比有氧受照细胞的DNA链断裂重接快且完全。照后持续乏氧保温可抑制乏氧受照细胞的DNA链断裂重接。再氧合可促进DNA链裂重接过程。

In this paper we described a modified fluorometric analysis ofDNA unwindingg method for the detection of DNA strand breaks in cells. Some fac-tors which might influence the results were also investigated, and the effect of oxygenon the induction of DNA strand breaks and its repair in γ-irradiated mammaliancells was observed, It was shown that a liner relationship existed between the doseand the extent of DNA damage. OER of L_(7712) cells was 3.0. while OER of 3T3 cellswere 1 .37 and 1 .01 under two different irradiation conditions. The differences betweenthem were an interested and significant question. Incubated at 37℃ under oxic condi-tion, the hypoxically irradiated 3T3 cells rejoined. their strand breaks more rapidlyand efficiently than the oxically irradiated cells did. Post-irradiation hypoxia couldinhibit the rejoining of strand breaks in the hypoxically irradiated 3T3 cells.