煤烟对大鼠肺Ⅱ型细胞DNA损伤作用的研究

DNA damage effects of soot on rat pulmonary type Ⅱ cells

目的 探讨煤烟对大鼠肺Ⅱ型细胞DNA的损伤作用。方法 采用单细胞凝胶电泳法 (SCGE)和溴乙锭荧光法 (EFA)结合细胞原代培养技术检测了煤烟颗粒提取物对大鼠肺Ⅱ型细胞DNA单链断裂作用和双链交联形成作用。结果 煤烟颗粒提取物在 15～ 12 0mg/L的浓度范围内具有细胞毒性 ,受试物剂量和检测到的A值存在剂量 反应关系 (r=-0 943 ,P <0 0 5 )。在 10～ 40mg/L的剂量范围内可以引起细胞DNA发生单链断裂和DNA双链交联作用。与对照组相比 ,各剂量组检测到的DNA交联率分别增加了 18 2 %、2 3 7%和 3 1 4% ,最高剂量组检测到的平均彗尾长度是对照组的 3 6倍。结论 煤烟可以导致肺Ⅱ型细胞DNA的损伤。

Objective To detect DNA damage of soot on rat pulmonary cells. Methods The ethidium bromide fluorescence assays (EFA) and single cell gel electrophoresis(SCGE) were applied to study the interstrand DNA cross-links and DNA single strand breaks of soot on rat pulmonary type Ⅱ cell. Results The soot extracts could result in cytotoxicity at dose of 15-120 mg/L. Compared with untreated group, they had statistical difference, and dose-responsive relationships between exposure and MTT conversion were found (r=-0.943, P<0.05). At the same time, the results showed that the soot extracts could cause interstrand DNA cross-links and DNA single strand breaks of pulmonary cell DNA at the dosage of 10-40 mg/L. The occurrence of DNA cross-links appeared to have increased 18.2%, 23.7% and 31.4% respectively in every dose group, and the extent of DNA strand breaks in the high dose group could be induced up to 3.6 fold compared to that of control group. Conclusion It suggested that the soot could lead to cytotoxicity and DNA damage of rat pulmonary type Ⅱ cell.