BPDE-DNA加合物体外生成实验研究

THE STUDY OF FORMATION OF BPDE-DNA ADDUCTS IN VITRO

目的:探讨体外合成苯并(a)芘与DNA形成加合物的条件。方法:以一定比例混合苯并(a)芘丙酮溶液、DNA溶液、S9混合液、于37℃孵育24 h后,紫外分光光度计扫描DNA图谱,得出DNA结构改变的信息;同时用HPLC检测反应体系中的苯并(a)芘含量、苯并(a)芘代谢物及DNA加合物酸水解后的产物。确定BPDE-DNA加合物生成,质谱验证生成物的结构。结果:反应后DNA紫外最大吸收峰红移;HPLC检测发现孵育后反应体系中苯并(a)芘含量降低,反应管有新的物质生成;质谱分析生成物的分子量同于目标产物。结论:一定条件下体外可合成苯并(a)芘-DNA加合物。

Objective： To study the formation conditions of BPDE - DNA adducts in vitro. Methods： After incubation of the mixtures of BaP, DNA, S9 at a certain proportion at 37℃ for 24 hours, the ultraviolet spectrum of the mixtures was scanned with a UV spectrophotometer, and the spectrum indicated that DNA＇ s structure has been changed. The measurement of BaP, BaP metabolite and acid - hydrolysis products of DNA adducts by HPLC indicated that there were BPDE- DNA adducts. And finally the formation of （7R, 8S） - dihydroxy - （9S, 10R） - epoxy - 7, 8, 9, 10 - tetrahydro benzo [a] pyrene （BPDE） was con- firmed by I-tPLC- MS. Results： The UV wavelength of the maximum absorption of DNA after incubation with S9 has been red shift compared with that of BoP, and there appeared a new peak in the incubation mixture with S9 in the HPLC chromatogram. The new peak was confirmed by HPLC- MS to be tetraol - BaP. Conclusions： Under the experimental condition, BaP could be transformed to （7R, 8S） -dihydroxy- （9S, 10R） -epoxy-7, 8, 9, 10- tetrahydro benzo [a] pyrene （BPDE）, and to form BPDE - DNA adducts.