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目的 观测过氧化氢诱导的大鼠衰老神经细胞 DNA损伤与修复情况。 方法 在荧光显微镜下观察不同浓度 H2 O2 处理的 3月、8月和 2 6月龄大鼠的脑皮质、海马和基底节经分离的神经细胞及氧化损伤断裂的单链 DNA,并做彗星图像分析。 结果 在相同浓度 H2 O2 介导下 ,衰老神经细胞 DNA损伤分值较正常神经细胞高 ,皮质细胞较海马、基底节区细胞 DNA损伤分值高 ,细胞更易受损伤。给予 0 .5～ 4 .0 h孵育后 ,表明脑细胞最大修复时间仅为 1 .0 h,且衰老神经细胞较正常神经细胞的 DNA损伤分值高 ,修复能力下降。当 H2 O2 介导浓度为 64μmol/L时 ,3月龄鼠脑皮质、海马和基底节神经细胞 DNA损伤分值依次为 2 50、2 1 3和 2 0 5,2 6月龄鼠 DNA损伤分值依次为 3 55、3 4 0和 3 3 5。当 H2 O2 介导浓度为 1 2 8μmol/L时 ,2 6月龄鼠 DNA修复率约为 1 0 %。 结论 彗星实验是一种非常敏感的检测 DNA损伤与修复的方法。
Objective To observe the hydrogen peroxide - induced DNA damage and repair of rat aged neurons. Methods The neurons isolated from cerebral cortex, hippocampus and basal ganglia treated with different concentrations of H2O2 and single-stranded DNA fragmented by oxidative damage were observed under fluorescence microscope in March, August and February, analysis. Results Under the same concentration of H2O2, DNA damage score of aged neurons was higher than that of normal nerve cells. The DNA damage scores of cortical cells in hippocampus and basal ganglia were higher, and cells were more easily damaged. After 0.5 ~ 4.0 h incubation, the maximal recovery time of brain cells was only 1.0 h, and the senescent nerve cells had higher DNA damage scores and lower repair ability than normal nerve cells. DNA damage scores of cerebral cortex, hippocampus and basal ganglia neurons in 3-month-old mice were DNA damage scores of 2 50, 21 3, and 20 5, 26 months old rats, respectively, when the H2O2-mediated concentration was 64 μmol / The values are 3 55,3 4 0 and 3 3 5. When the H2O2-mediated concentration of 128μmol / L, 26-month-old mouse DNA repair rate of about 10%. Conclusion Comet assay is a very sensitive method to detect DNA damage and repair.