【摘要】 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。更多还原

【Abstract】 Objective An observation of H 2O 2 induced DNA damage and the kinetics of DNA repair in senescent murine brain cells with alkaline single cell gel electrophoresis (SCGE/Comet assay) was made. Methods The dissociated brain cells harvested in the area of cerebral cortex, hippocampus, basal ganglion from 3 month,8 month and 26 month old rats were respectively treated with H 2O 2 in different doses. Individual image was recorded, digitalized and measured with Image Analysis System. Results A linear increase was noticed in vulnerability of DNA both with respect to H 2O 2 doses and aging. As to the damaged region of the brain, the cortical cells were more vulnerable to the insult than the hippocampal and basal ganglionic cells. Whatever the age of the cells were, the maximal ratio of DNA repair was only seen within 1 hour during an incubation period of 0 5 4 0 hours after the insult. Furthermore, the ratio of DNA repair of sick cells will be less with aging. DNA damage score of cerebral cortex, hippocampus, basal ganglion from 3 month rats was 250,213, 205 and 355,340,335 from 26 month rats ,when treated with H 2O 2 in 64 μmol/L. The ratio of DNA repair in aging brain cells was about 10% when treated with H 2O 2 in 128 μmol/L. Conclusions Comet assay is a sensitive way to check DNA damage and repair of the cells. It should be more difficult for the cells to cope with an acute and excessive than with a persistent, chronic and mild DNA damage which is more related to an accumulating injury i.e. aging.更多还原