Nacci Diane E, Kohan Michael, Pelletier Marguerite, George Elizabeth
US Environmental Protection Agency, Office of Research and Development, Atlantic Ecology Division, 27 Tarzwell Drive, Narragansett, RI 02882, USA.
Aquat Toxicol. 2002 Jun;57(4):203-15. doi: 10.1016/s0166-445x(01)00196-5.
Effects of a model polycyclic aromatic hydrocarbon (PAH) were compared in populations of the estuarine fish Fundulus heteroclitus indigenous to a reference site and one highly contaminated with polychlorinated biphenyls (PCBs) and other compounds. The fish population resident to the PCB-contaminated site is genetically resistant to those PCB congeners categorized as dioxin-like compounds (DLCs) that act through the aryl hydrocarbon receptor (AHR). In response to DLC exposures, these DLC-resistant fish showed poor inducibility for enzymes known to be regulated by the AHR pathway and important for the metabolism of xenobiotics including some PAHs that also act as AHR agonists. Therefore, a laboratory study using the model PAH, benzo[a]pyrene (BaP), was conducted to evaluate how PAHs might affect these wild fish populations that differed in their inherent sensitivities to DLCs and in their tissue concentrations of contaminants. Following BaP treatment, the activities of two xenobiotic metabolizing enzymes and the concentrations of BaP-DNA adducts, as measured using the 32P-postlabeling method, were lower in the livers of DLC-resistant than reference fish. These results suggest that DLC-resistance could provide protection following chronic exposures to PAHs from the long-term consequences of DNA adduct formation, such as cancer. Alternatively, reduced metabolism and elimination of toxic or photo-activated PAHs could have acute consequences to the health and reproduction of these DLC-resistant fish and their progeny. These fish populations provide useful models to evaluate the potential costs and benefits of genetic adaptation in wildlife populations subject to anthropogenic stress.
在一个参考地点的河口鱼类——红腹原灯𫚥虎鱼的种群，以及一个被多氯联苯（PCBs）和其他化合物高度污染的地点的红腹原灯𫚥虎鱼种群中，对一种典型多环芳烃（PAH）的影响进行了比较。居住在受多氯联苯污染地点的鱼类种群，对那些通过芳烃受体（AHR）起作用、被归类为二恶英类化合物（DLCs）的多氯联苯同系物具有遗传抗性。在接触二恶英类化合物后，这些对二恶英类化合物有抗性的鱼类，对于那些已知受芳烃受体途径调控、对包括一些也作为芳烃受体激动剂的多环芳烃在内的外源性物质的代谢很重要的酶，诱导能力较差。因此，进行了一项使用典型多环芳烃苯并[a]芘（BaP）的实验室研究，以评估多环芳烃如何影响这些对二恶英类化合物的固有敏感性及其组织污染物浓度不同的野生鱼类种群。在苯并[a]芘处理后，使用32P后标记法测量，对二恶英类化合物有抗性的鱼类肝脏中两种外源性物质代谢酶的活性以及苯并[a]芘-DNA加合物的浓度，均低于参考鱼类。这些结果表明，对二恶英类化合物的抗性，可能在长期接触多环芳烃后，对DNA加合物形成的长期后果（如癌症）提供保护。或者，多环芳烃的代谢和消除减少，可能会对这些对二恶英类化合物有抗性的鱼类及其后代的健康和繁殖产生急性影响。这些鱼类种群为评估在受到人为压力的野生动物种群中遗传适应的潜在成本和益处，提供了有用的模型。
