甲醛致中华卵索线虫DNA损伤作用的研究

Study on DNA damages of Ovomermis sinensis induced by formaldehyde

为了探讨甲醛致线虫DNA-蛋白质交联(DNA-proteincrosslinks,DPC)和DNA断裂(DNAstrandbreakage,DSB)的作用,以中华卵索线虫(Ovomermissinensis)为材料,经活体染毒后,采用KCl-SDS沉淀法和单细胞凝胶电泳法来检测液态甲醛染毒后线虫提取细胞中DNA-蛋白质交联物的含量及DNA的断裂效应.KCl-SDS沉淀法的结果表明,低浓度(5、25、125μmol·L-1)的液态甲醛不能引起DNA-蛋白质的交联(p>0·05),较高浓度(625μmol·L-1)的甲醛可以引起明显的DNA-蛋白质的交联作用(p<0.05).而单细胞凝胶电泳的结果则显示甲醛在低浓度(5、25μmol·L-1)时可以引起DNA链的断裂(p<0.01),在较高浓度(125、625μmol·L-1)时可以引起交联作用(p<0.05).研究结果表明,甲醛在较高浓度时可以导致明显的DNA-蛋白质交联作用,而在小于25μmo·lL-1时以DNA断裂作用为主.

To explore the effect of DNA-protein crosslinks （DPC） and DNA strand breakage（DSB） induced by formaldehyde in nematode,this study took Ovomermis sineasis as experimental material and made use of KCI-SDS assay and comet assay to determine the amount of DNA-protein crosslinks and effect of DNA strand breakage , with exposure to liquid formaldehyde in vivo. From the results of KCl-SDS assay formaldehyde at low levels （5, 25, 125 μmol·L^-1 ） can not cause DPC significantly （p 〉 0. 05 ）, but at higher levels （ 625 μmol·L^-1 ,p 〈0. 05 ） causes DPC obviously. According to the results of comet assay, it can cause DNA strand breakage （DSB） at low levels （5 and 25 μmol·L^-1 P 〈 0. 01 ） and cause crosslinks at higher levels （ 125 and 625 μmol·L^-1 ,p 〈 0. 01 ）. From the above results we can conclude that formaldehyde can cause DPC at higher levels, at lower 25μmol· L^-1 the general effect is DSB.