甲基叔丁基醚致人B淋巴母细胞系DNA损伤和氧化应激损伤的研究
Study of DNA Damage and Oxidative Stress of Human B Lymphocytes Induced by Methyl Tert-Butyl Ether
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摘要:
目的 通过体外实验研究甲基叔丁基醚（MTBE）染毒对人B淋巴母细胞系DNA损伤和氧化应激水平的影响。
方法 将处于对数生长期的人B淋巴母细胞系分别以1.25、2.5、5、10、12.5 μmol/L的MTBE溶液染毒，24 h后分别收集细胞和上清液，用彗星试验检测人B淋巴细胞染毒后的尾部DNA百分比及Olive尾矩；同时，用ELISA试剂盒检测细胞上清液中的丙二醛（MDA）、谷胱甘肽过氧化物酶（GSH-Px）和8-羟基脱氧鸟苷（8-OHdG）水平，并对MTBE浓度和这些指标之间的关系进行相关性分析。
结果 MTBE染毒24 h后，人B淋巴母细胞系在5、10、12.5 μmol/L剂量组的尾部DNA百分比及Olive尾矩均高于对照组（均
P <0.01）；1.25、2.5、5、12.5 μmol/L组8-OHdG水平高于对照组（P <0.05）；除10 μmol/L组的MDA之外，各组MDA、GSH-Px水平均未见明显改变。MTBE浓度和尾部DNA百分比及Olive尾矩之间呈正相关关系（r =0.685，P =0.000；r =0.615，P =0.000）。结论 低剂量MTBE染毒可以诱导人B淋巴母细胞系发生DNA损伤，DNA损伤可以作为反映MTBE毒性效应的一项较敏感的指标。
Abstract:Objective To examine the DNA damage and oxidative stress in human B lymphocytes exposed to different concentrations of methyl tert-butyl ether (MTBE).
Methods Human B lymphocytes were exposed to MTBE at concentrations of 1.25,2.5,5,10,12.5 μmol/L for 24 h,separately.Then the treated cells were harvested to test percentage of tail DNA and Olive tail moment by using the comet assay.Meanwhile,the levels of malondialdehyde (MDA),glutathione peroxidase (GSH-Px),and 8-hydroxydeoxyguanosine (8-OHdG) in cell supernatant were detected by ELISA.Additionally,a correlation analysis was carried out between the concentrations of MTBE and the selected indicators.
Results After the cells were treated for 24 h,the percentage of tail DNA and the olive tail moment in the groups exposed to 5,10,and 12.5 μmol/L MTBE were significantly higher than those in the control group (all
Ps <0.01).As for the oxidative stress,the 8-OHdG levels were elevated in the groups exposed to 1.25,2.5,5,and 12.5 μmol/L MTBE compared to the control group (P <0.05);however,except the 10 μmol/L MTBE group,the MDA and GSH-Px levels in the other exposed groups showed no significant change,compared with those in the control group.And there was a significant positive correlation between the concentrations of MTBE and percentage of tail DNA and the Olive tail moment (r =0.685,P =0.000;r =0.615,P =0.000).Conclusion The study findings indicate that a low concentration of MTBE could induce DNA damage of human B lymphocytes,and DNA damage could be used as a sensitive indicator of MTBE toxicity.
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