苯DNA加合物的形成特征、条件和方法探讨

Studies on the characteristics and appropriate conditions and methods of benzene DNA adduct formation in vivo

为进一步探讨苯ＤＮＡ加合物的形成特征，稳定地检测苯ＤＮＡ加合物，采用３２Ｐ－后标记法对染苯小鼠体内ＤＮＡ加合物的形成特征及影响因素进行了研究。结果表明：加合物种类与染苯天数有关：５００ｍｇ／ｋｇ染苯５天组外周血白细胞可检出２个ＤＮＡ加合物斑点，而７天组可检出３个主要的和至少１个微弱的加合物斑点；染苯达一定剂量后，加合物含量和种类不再增加，１０００ｍｇ／ｋｇ与５００ｍｇ／ｋｇ染苯７天组的检测结果基本相同；苯醌可能是苯形成ＤＮＡ加合物的主要代谢产物，２．５ｍｇ／ｋｇ苯醌染毒５天的小鼠白细胞中可检出３个主要的及２个微弱的加合物斑点，其层析特性与染苯小鼠加合物的层析性质基本一致。提示：动物染苯天数及次数、层析点样量及层析时间对加合物斑点形成均有影响。

DNA adducts in peripheral leucocytes of mice injected intraperitoneally with high dose of benzene were analyzed by 32 P postlabelling assay.At least three major DNA adducts and one minor DNA adduct could be detected in the mice treated with 500 mg/kg benzene twice a day for 7 days.The result of 1 000 mg/kg benzene group was the same as that of 500 mg/kg benzene group.The value of adducts was not increasing while the benzene reached to a certain level.Three major and two minor DNA adducts were detected in the mice treated with 2.5 mg/kg benzoquinone.In vivo ,the treatment of benzene produced the same DNA adducts as found after treatment with benzoquinone.This result suggested benzoquinone may be the principal metabolite of benzene leading to DNA adduct formation in vivo . It was suggested there were certain influences to DNA adduct formation caused by benzene,such as treated days and frequencies,volume of sample loaded and time for thin layer chromatography.