CAJ | 학술논문

离体条件下，以大白鼠肝癌细胞株H4IIE的7-乙氧基-3-异吩恶唑酮-脱乙基酶（EROD）活力诱导作为毒性指标，测定了2,3,7,8-TCDD单独存在以及与一定浓度的2,3,7,8,-TCDF, OCDD, PCB126和PCB77分别共存下的EROD活力，并用TEF和独立作用模型（independence）两种方法对实验结果进行了评估。利用TEF评估的结果表明实验的TEQ值和理论计算的TEQ值十分接近，复合毒性表现为加合作用（additivity），这一结果与用独立作用模型评估的结果完全一致。研究结果不仅证实了TEF评估方法的有效性和利用模型方法评估二恶英类化合物复合毒性的可行性，同时还表明离体条件下，大白鼠肝癌细胞株H4IIE的EROD酶活力诱导适用于化合物的复合毒性的研究。
리체조건하，이대백서간암세포주H4IIE적7-을양기-3-이분악서동-탈을기매（EROD）활력유도작위독성지표，측정료2,3,7,8-TCDD단독존재이급여일정농도적2,3,7,8,-TCDF, OCDD, PCB126화PCB77분별공존하적EROD활력，병용TEF화독립작용모형（independence）량충방법대실험결과진행료평고。이용TEF평고적결과표명실험적TEQ치화이론계산적TEQ치십분접근，복합독성표현위가합작용（additivity），저일결과여용독립작용모형평고적결과완전일치。연구결과불부증실료TEF평고방법적유효성화이용모형방법평고이악영류화합물복합독성적가행성，동시환표명리체조건하，대백서간암세포주H4IIE적EROD매활력유도괄용우화합물적복합독성적연구。
Polyhalogenated aromatic hydrocarbons (PHAHs) such as polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and biphenyls (PCB) are persistent environmental pollutants, which are able to bioaccumulate through the food chain and pose a series health risk to humans and animal species. Since the environmental biota is exposed to mixtures of these compounds rather than to the single congener, simultaneous or sequential exposure of organism to two or more these compounds may alter quantitative and qualitative biological response. Therefore, studies with mixtures could provide more information about the possible interactive effects between these compounds and the fundamental mechanisms behind these interactive effects. 　　In this study, the activities of five individual PHAHs (TCDD, TCDF, OCDD, PCB77 and PCB126) and their mixtures as inducers of ethoxyresorufin-O-deethylase (EROD) in rat hepatoma H4IIE cells were determined. The EROD activity in intact cells seed on 96 well plates was determinated according to Donato et al. modified as follows: Cells were seeded at a density of 1×104/well in a 96-well plate. After 3 days the medium was replaced with 100μl medium containing samples extract or TCDD standard. After 72hr the medium was removed and 100μl fresh medium containing 8 μmol 7-ethoxyresorufin and 10 μmol dicumarol were added. After incubation for 60min at 37℃ the medium was transferred to a fresh 96-well plate and 130μl methanol were added. Resorufin-associated fluorescence was measured in these solutions on a multiwell fluorescence reader. The 96-well plate containing the remaining live cell cultures was for a cytotoxicity test using the neutral red assay, Thereafter the protein content per well was assayed using bicinchoninic acid. Standard deviations between triplicates remained ＜10% 　　In EROD bioassay, The individual EC50-values and toxic equivalency factors (EROD-TEFs) for TCDF, OCDD, PCB77 and PCB126, were in good agreement with international TEFs (I-TEFs). Toxic effects of 2,3,7,8-TCDD alone and in the presence of 2,3,7,8-TCDF, OCDD, PCB126, PCB77 as inducers of ethoxyresorufin-O-deethylase (EROD) in rat hepatoma H4IIE cells were assessed by TEF and independence model respectively. The results from TEF showed that the difference between the experimental and calculated TEQs for these mixtures was minimal while the interactions were perfectly additive. These were in good agreement with the results from the model assessment. This study not only confirms the utility of the TEF approach and the feasibility of the modelling, but also indicates that the in vitro induction assay is useful for mixtures.