用~(32)P后标记方法测定职业接触苯乙烯工人静脉血中DNA-环氧苯乙烯加合物

用~(32)P后标记方法,对一组22例接触苯乙烯的工人和8例未接触苯乙烯(空白)的工人进行测试,其静脉血中的淋巴细胞有4例(高浓度,大于40ppm)发现DNA-环氧苯乙烯加合物;而另外接触高浓度苯乙烯、低浓度苯乙烯和空白试样中,均未发现。在已测出的4例中,加合物形成水平为0.07—3.38加合物/10~7正常核酸,DNA的总损伤水平为5—9加合物/10~7正常核酸。 用小牛胸腺DNA、四种脱氧核苷3′-单磷酸分别与环氧苯乙烯进行体外反应,然后用~(32)P后标记法测定产物中的DNA加合物,初步确证有六种加合物及其衍生物存在,修饰位置是鸟苷碱基。并确证了其中三种加合物的化学结构,另外几种加合物的结构有待进一步鉴定。 ~(32)P后标记法测DNA加合物,灵敏度高达1加合物/10~(10)正常核酸,近于人体二倍体细胞基因水平(1.2×10~(10)碱基)。

DETERMINATION OF STYRENE OXIDE-DNA ADDUCTS IN LYMPHOCYTES FROM WORKERS OCCUPATIONLLY EXPOSED TO STYRENE BY 32p_poSTLABELING

A sensitive method of 32P-postlabeling was used to determine DNA-styrene oxide adducts in lymphocytes from workers oecupation-lly exposed to styrene. Six DNA-styrene oxide adducts and deriva-ties were determined in four samples from workers occupationlly exposed to high concentration of styrene (>40ppm) and no adduct was detected in other 26 samples from workers occupationlly exposed to lower concentration of styrene and the controls. The total level of modification in lymphocytes from workers exposed to styrene was (5-9)XXX10-7 adducts/normal nucleotides.The number and position of DNA-styrene oxide adducts on the autoradiogram examined by 82P-postlabeling in lymphocytes were similar to the retults detected in samples interacted DNA and dGmP with styrene oxide in vitro. The structures of three adducts determined by 32P-postlabeling were identificated to be O6-(2-hydroxy-2-phenylethyl)-2-deoxyguanosine 3'-phosphate, O6-(2-hydroxy-1-phe-nylethyl)-2'-deoxyguanosine-3'-phosphate and N2-(2-hydroxy-l-phe-nylethyl)-2'-deoxyguanosine-3' -phosphate.Further sdudies are required for identifiying other adducts.