Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry - LABCAI, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil.
Aquaculture Pathology Research Center - NEPAQ, Federal University of Santa Catarina, UFSC, Florianópolis, Brazil.
Aquat Toxicol. 2019 Nov;216:105318. doi: 10.1016/j.aquatox.2019.105318. Epub 2019 Sep 27.
Polycyclic aromatic hydrocarbons (PAHs) are among the main contaminants in aquatic environments. PAHs can affect organisms due to their carcinogenic, mutagenic and/or teratogenic characteristics. Depending on the PAHs, concentration, and period of exposure, biological damage can occur leading to histopathologic alterations. This study aimed to evaluate the molecular, biochemical and histological responses of the oyster Crassostrea gasar exposed to pyrene (0.25 and 0.5 μM) and fluorene (0.6 and 1.2 μM), after exposure for 24 and 96 h. Concentrations of both PAHs were quantified in the water and in oyster tissues. Transcript levels of phase I (CYP3475C1, CYP2-like, CYP2AU1 and CYP356A) and phase II (GSTO-like, MGST-like and SULT-like) biotransformation-related genes and the activities of ethoxyresorufin-O-deethylase (EROD), total and microsomal glutathione S-transferase (GST and MGST) were evaluated in the gills. Also, histological changes and localization of mRNA transcripts CYP2AU1 in gills, mantle, and digestive diverticula were evaluated. Both PAHs accumulated in oyster tissues. Pyrene half-life in water was significantly lower than fluorene. Transcript levels of all genes were higher in oysters exposed to of pyrene 0.5 μM (24 h). Only CYP2AU1 gene was up-regulated by fluorene exposure. EROD and MGST activities were higher in oysters exposed to pyrene. Tubular atrophy in the digestive diverticula and an increased number of mucous cells in the mantle were observed in oysters exposed to pyrene. CYP2AU1 transcripts were observed in different tissues of pyrene-exposed oysters. A significant correlation was observed between tubular atrophy and the CYP2AU1 hybridization signal in oysters exposed to pyrene, suggesting the sensibility of the species to this PAH. These results suggest an important role of biotransformation-related genes and enzymes and tissue alterations associated to pyrene metabolism but not fluorene. In addition, it reinforces the role of CYP2AU1 gene in the biotransformation process of PAHs in the gills of C. gasar.
多环芳烃 (PAHs) 是水生环境中的主要污染物之一。由于其致癌、致突变和/或致畸特性，PAHs 会影响生物体。根据 PAHs 的种类、浓度和暴露时间，可能会导致生物损伤，从而导致组织病理学改变。本研究旨在评估在暴露于芘 (0.25 和 0.5 μM) 和荧蒽 (0.6 和 1.2 μM) 24 和 96 小时后，贻贝 Crassostrea gasar 的分子、生化和组织学反应。在水中和贻贝组织中定量了两种 PAHs 的浓度。评估了相 I（CYP3475C1、CYP2 样、CYP2AU1 和 CYP356A）和相 II（GSTO 样、MGST 样和 SULT 样）生物转化相关基因的转录水平，以及在鳃中测定了乙氧基 RESO 脱乙基酶 (EROD)、总谷胱甘肽 S-转移酶 (GST 和 MGST) 和微粒体谷胱甘肽 S-转移酶 (MGST) 的活性。还评估了在鳃、套膜和消化憩室中 CYP2AU1 基因的 mRNA 转录物的组织学变化和定位。两种 PAHs 均在贻贝组织中积累。水中芘的半衰期明显低于荧蒽。暴露于 0.5 μM 芘 24 小时的贻贝中所有基因的转录水平均较高。仅在暴露于荧蒽的贻贝中上调了 CYP2AU1 基因。暴露于芘的贻贝中 EROD 和 MGST 活性较高。在暴露于芘的贻贝中观察到消化憩室的管状萎缩和套膜中粘液细胞数量增加。在暴露于芘的贻贝中观察到 CYP2AU1 转录物在不同组织中。在暴露于芘的贻贝中，管状萎缩与 CYP2AU1 杂交信号之间观察到显著相关性，表明该物种对这种 PAH 的敏感性。这些结果表明，与芘代谢相关的生物转化相关基因和酶以及组织改变在贻贝中具有重要作用，但与荧蒽无关。此外，它加强了 CYP2AU1 基因在 C. gasar 鳃中 PAHs 生物转化过程中的作用。
