鲫鱼肝脏中CYP1A1的诱导作为沉积物中二的毒理学指标的研究

在实验室内用鲫鱼分别暴露于含有PCDD/Fs和PCBs严重污染的沉积物和未受污染的沉积物中，测定鱼肝脏中细胞色素P4501A1（CYP1A1）依赖的7－乙氧基－3－异吩唑酮－脱乙基酶（EROD）的活性。结果表明，鲫鱼暴露于受二类化合物污染沉积物中1周后，肝脏中EROD的活性是对照组的83倍，而未被污染的沉积物暴露试验中EROD的活性和对照组没有明显差别。在此沉积物－水实验系统中二类污染物的TCDD等当量浓度（TEQ/L）与肝脏EROD的活性有较好的相关性。较长时间暴露，得到肝脏EROD的活性随时间的变化关系。还获得了试验温度对EROD活性诱导的影响。此实验表明，用实验室鲫鱼暴露于沉积物－水系统中，鱼肝脏EROD活性诱导可作为沉积物毒性评价指标，用于受二类化合物污染的沉积物样品的筛选，并有希望成为此类污染物的半定量检测方法。

CYP 1A1 induction in silver curcian carp liver as a biomarker in assessment of contaminated sediments

Hepatic monooxygenase activity can be easily induced by dioxin like compounds and measurement of this activity has been proposed as an environmental biomaker.Hepatic cytochrome P450 1A1 inductions were investigated by ethoxyresorufin o deethylase(EROD) activity,after silver curcian carp (Carassius auratu) were exposed to sediment highly contaminated with polychlorodibenzo p dioxins (PCDDs),polychlorodibenzofurans (PCDFs) and polychlorobiphenyls(PCBs),or relatively unpolluted sediments in laboratory.The results showed 83 fold hepatic EROD induction in the dioxins polluted sediment exposure vs the control group;while no significant difference between the unpolluted sediments and the control.A good relationship between the hepatic EROD activity and the dioxin like compounds concentration(TEQ/L) in the sediment water system in one week exposure was obtained,and a time response of EROD activity was observed after four weeks polluted sediment exposure.The influences of test temperature on EROD activity were also investigated in laboratory.These results indicate that the fish hepatic EROD induction after sediment exposure can be used to assess sediment toxicity,and the induction may be useful for screening and semi quantitative bioassay for dioxin like compounds in the sediment.