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目的 以体外培养的人肺泡上皮细胞 (A549)作为靶细胞 ,探讨煤尘对DNA的损伤作用。方法 将人肺泡上皮细胞 (A549)用 3种煤尘作用 2h或 2 4h,用MTT法测定细胞存活情况及用单细胞凝胶电泳技术测定DNA链断裂情况 ;采用两种细胞共培养的方法 ,用MTT法测定煤尘在巨噬细胞介导作用下对A549细胞存活情况的影响及用单细胞凝胶电泳技术测定DNA链断裂情况。结果 3种煤尘 (游离SiO2 含量分别为 4 33%、1 79%、0 67% )以 3种剂量 (1 0 0、50 0、1 0 0 0 μg ml)直接作用于A549细胞 2 4h,在 50 0和1 0 0 0 μg ml时均可引起细胞存活率的明显下降 ;直接作用于A549细胞 2h或 2 4h及通过巨噬细胞介导作用下A549细胞 ,均未能引起A549细胞DNA链断裂程度的明显增加。结论 煤尘对A549细胞具有明显的细胞毒性 ,但不具有明显的遗传毒性
Objective To investigate the effect of coal dust on DNA damage by using human alveolar epithelial cells (A549) cultured in vitro as target cells. Methods Human lung alveolar epithelial cells (A549) were treated with 3 kinds of coal dust for 2 hours or 24 hours. MTT assay was used to determine cell viability and DNA strand breaks were determined by single cell gel electrophoresis. The effect of coal dust on the survival of A549 cells under the mediation of macrophages was determined by MTT method and the DNA strand breaks were determined by single cell gel electrophoresis. Results The three kinds of coal dusts (free SiO2 contents were 433%, 1 79% and 0 67% respectively) were directly treated with A549 cells at 3 doses (100, 500, 100 microg x ml) for 24 hours, At 50 and 100 microg ml, the cell viability decreased significantly. A549 cells directly induced A549 cells 2h or 24h and A549 cells via macrophages failed to cause DNA chain Significant increase in the degree of fracture. Conclusion Coal dust has obvious cytotoxicity to A549 cells but not obvious genotoxicity