目的 观察氢醌诱导体外细胞DNA甲基化水平改变,探讨聚ADP-核糖聚合酶l[poly (ADP-ribose)polymerasel,PARPl]在该过程中的作用.方法 以10、20、40、60、80 μmol/L浓度的氢醌分别处理人支气管皮细胞(16HBE)及其PARPl缺陷细胞(16HBE-shPARPl)48 h,对照组加入等体积的PBS溶液.采用高效毛细管电泳检测基因组DNA整体甲基化水平,检测PARPl和DNA甲基转移酶1(DNA methyltransferases 1,DNMT1)mRNA表达的变化.结果 16HBE和16HBE-shPARPl细胞基因组整体甲基化百分比(mCpG％)分别为(4.89％±0.07％)和(9.53％±0.51％).经5-氮杂脱氧胞苷(DAC)处理72 h后,mCpG％值分别下降为(3.07％±0.12％)和(6.34％±0.3％),经单因素方差分析,2种细胞不同处理组mCpG％的差异有统计学意义(F值为61.25和60.36,均P＜0.01).16HBE细胞各氢醌染毒组的PARP1 mRNA相对表达分别为对照组的145.0％、159.0％、169.0％、215.0％和236.0％,差异均有统计学意义(P＜0.01);16HBE-shPARPl细胞,各氢醌染毒组PARPl mRNA相对表达水平分别为对照组的170.0％、223.0％、264.0％、327.0％和320.0％,差异均有统计学意义(P＜0.01).当氢醌染毒剂量达到20、40、60、80μmol/L,16HBE细胞DNMTl mRNA相对表达水平分别为对照组的114.0％、126.0％、136.0％和162.0％,差异有统计学意义(均P＜0.01);当氢醌染毒剂量达10、20、40、60、80 μmol/L,16HBE-shPARPl细胞DNMTl mRNA相对表达水平分别为对照组的141.0％、165.2％、186.9％、202.1％和217.3％,差异有统计学意义(P＜0.01).结论 氢醌能引起16HBE细胞低甲基化,PARPl可通过影响DNMTl的表达及改变DNMT1的活性来调节16HBE细胞DNA甲基化改变.%Objective To investigate the DNA methylation changes induced by hydroquinone (HQ) in human bronchial epithelial cells and to explore the role of poly(ADP-ribose) polymerase-l (PARP-l) in this process.Methods Human bronchial epithelial 16HBE cells and PARP-l-deficient 16HBE cells (16HBE-shPARP-lcells) were exposed to HQ (10,20,40,60,and 80 μmol/L) for48 h,while control cells were treated with an equal volume of PBS solution.The changes in genomic DNA methylation were investigated by high-performance capillary electrophoresis,and the expression levels of PARP-l and DNA methyltransferase 1 (DNMT1) were measured.Results The percentages of methylated DNA of overall genome (mCpG％) in 16HBE and 16HBE-shPARP-l cells were 4.89％±0.07％ and 9.53％±0.51％,respectively; after treatment with 5-aza-2'-deoxycitidine for 72 h,mCpG％ decreased to 3.07±0.12％ and 6.34％±0.3％,respectively.The one-way analysis of variance revealed significant differences in mCpG％ between the cells exposed to different concentrations of HQ in both 16HBE and 16HBE-shPARP-l groups (F=61.25,P＜0.01; F=60.36,P＜0.01).For 16HBE cells treated with HQ (10,20,40,60,and 80 μmol/L),the mRNA expression levels of PARP-1 were 145.0％,159.0％,169.0％,215.0％,and 236.0％,respectively,compared with those in the control group,with significant differences (P＜0.01 for all); for 16HBE-shPARP-l cells treated with HQ (10,20,40,60,and 80 μmol/L),the mRNA expression levels of PARP-l were 170.0％,223.0％,264.0％,327.0％,and 320.0％,respectively,compared with those in the control group,with significant differences (P＜0.01 for all).When the dose of HQ reached 20,40,60,and 80 μmol/ L,the mRNA expression levels of DNMT1 in 16HBE group were 114.0％,126.0％,136.0％,and 162.0％,respectively,compared with those in the control group,with significant differences (P＜0.01 for all); when the dose of HQ reached 10,20,40,60,and 80 μmol/L,the mRNA expression levels of DNMT1 in the 16HBE shPARP-l group were 141.0％,165.2％,186.9％,202.1％,and 217.3％,respectively,compared with those in the control group,with significant differences (P＜0.01 for all).Conclusion HQ can induce hypomethylation in 16HBE cells,and PARP-1 can regulate DNA methylation in 16HBE cells by influencing the expression and activity of DNMT1.
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