甲醛所致DNA-蛋白质交联修复的研究

为了探讨机体对甲醛所致DNA-蛋白质交联的修复能力,采用KCl-SDS沉淀法检测甲醛染毒后不同时间段HepG2细胞和小鼠肝细胞中DNA-蛋白质交联的修复情况.实验结果表明,采用75μmol·L-1甲醛染毒HepG2细胞,在染毒18h和24h后,细胞内的DPC水平较染毒结束时发生了显著下降(p<0.01),且与空白对照组相比无显著差异;由3.0mg·m-3气态甲醛产生的DNA-蛋白质交联在12h内可以得到明显修复(p<0.01),并在24h内恢复到空白对照水平;经20mg·kg-1液态甲醛染毒后,18h时DPC含量与空白组相比有显著性升高(p<0.01),在24h时DPC含量与18h时相比有显著的下降(p<0.05),且与空白组相比无显著差异.以上结果显示:甲醛所致肝细胞DNA-蛋白质交联能够得到修复,且24h内能够修复完全.

Study on the Repair of DNA-Protein Crosslinks Induced by Formaldehyde

To explore the repair process of DNA-protein crosslinks(DPC)induced by formaldehyde,this study used KCl-SDS assay to access the content of DPC in HepG2 cell line and the livers of purebred Kunming mice after exposure to formaldehyde at times of 0h,6h,12h,18h and 24h. The results showed that DPC,which was induced significantly by liquid formaldehyde at 75μmol·L-1,could be removed significantly after 18 and 24 hours(p < 0.01),but not the case after 6 and 12 hours. DPC induced by gaseous formaldehyde at 3.0mg·m-3 could be mostly removed within 12 hours (p < 0.01)and could be removed completely at 24 hours. DPC which was induced significantly after exposure to liquid formaldehyde at 20mg·kg-1(p < 0.01)could be removed within 24 hours,and the repair process of DPC mostly happened at the period of 18 to 24 hours. In combination,these results suggested that the DPC induced by formaldehyde could be removed completely in 24 hours.