Department of Biological Sciences, University of Wisconsin-Milwaukee, Lapham Hall, 3209 N. Maryland Ave., Milwaukee, WI 53211, USA.
Aquat Toxicol. 2013 Sep 15;140-141:356-68. doi: 10.1016/j.aquatox.2013.06.018. Epub 2013 Jul 1.
The goal of this project was to use functional genomic methods to identify molecular biomarkers as indicators of the impact of TCDD exposure in rainbow trout. Specifically, we investigated the effects of chronic dietary TCDD exposure on whole juvenile rainbow trout global gene expression associated with histopathological analysis. Juvenile rainbow trout were fed Biodiet starter with TCDD added at 0, 0.1, 1, 10 and 100 ppb (ngTCDD/g food), and fish were sampled from each group at 7, 14, 28 and 42 days after initiation of feeding. 100 ppb TCDD caused 100% mortality at 39 days. Fish fed with 100 ppb TCDD food had TCDD accumulation of 47.37 ppb (ngTCDD/g fish) in whole fish at 28 days. Histological analysis from TCDD-treated trout sampled from 28 and 42 days revealed that obvious lesions were found in skin, oropharynx, liver, gas bladder, intestine, pancreas, nose and kidney. In addition, TCDD caused anemia in peripheral blood, decreases in abdominal fat, increases of remodeling of fin rays, edema in pericardium and retrobulbar hemorrhage in the 100 ppb TCDD-treated rainbow trout compared to the control group at 28 days. Dose- and time-dependent global gene expression analyses were performed using the cGRASP 16,000 (16K) cDNA microarray. TCDD-responsive whole body transcripts identified in the microarray experiments have putative functions involved in various biological processes including growth, cell proliferation, metabolic process, and immune system processes. Nine microarray-identified genes were selected for QPCR validation. CYP1A3 and CYP1A1 were common up-regulated genes and HBB1 was a common down-regulated gene among each group based on microarray data, and their QPCR validations are consistent with microarray data for the 10 and 100 ppb TCDD treatment groups after 28 days exposure (p<0.05). In addition, in the 100 ppb group at 28 days, expression of complement component C3-1 and trypsin-1 precursor have a more than 10-fold induction from the microarray experiments, and their QPCR validations are consistent and showed significant induction in the 100 ppb group at 28 days (p<0.05). Overall, lesion in nasal epithelium is a novel and significant result in this study, and TCDD-responsive rainbow trout transcripts identified in the present study may lead to the development of new molecular biomarkers for assessing the potential impacts of environmental TCDD on rainbow trout populations.
本项目的目标是使用功能基因组学方法来识别分子生物标志物，作为 TCDD 暴露对虹鳟鱼影响的指示物。具体而言，我们研究了慢性饮食 TCDD 暴露对与组织病理学分析相关的整个幼年虹鳟鱼整体基因表达的影响。幼年虹鳟鱼用 Biodiet 起始饲料喂养，添加 0、0.1、1、10 和 100 ppb（ngTCDD/g 饲料）的 TCDD，喂食开始后第 7、14、28 和 42 天从每组中采样。100ppbTCDD 在 39 天引起 100%死亡率。喂食 100ppbTCDD 食物的鱼在 28 天时在整条鱼中积累了 47.37ppb（ngTCDD/g 鱼）的 TCDD。从 28 天和 42 天接受 TCDD 处理的虹鳟鱼的组织学分析显示，皮肤、咽峡、肝脏、气囊、肠道、胰腺、鼻子和肾脏都有明显的病变。此外，与对照组相比，100ppbTCDD 处理的虹鳟鱼在 28 天时外周血出现贫血、腹部脂肪减少、鳍射线重塑增加、心包水肿和球后出血。使用 cGRASP16000（16K）cDNA 微阵列进行了剂量和时间依赖性的全基因组基因表达分析。在微阵列实验中鉴定的 TCDD 反应性全身转录本具有参与各种生物过程的推定功能，包括生长、细胞增殖、代谢过程和免疫系统过程。选择了 9 个微阵列鉴定的基因进行 QPCR 验证。根据微阵列数据，CYP1A3 和 CYP1A1 是常见的上调基因，HBB1 是每组常见的下调基因，它们在 28 天暴露后的 QPCR 验证与微阵列数据一致（p<0.05）。此外，在 28 天的 100ppb 组中，补体成分 C3-1 和胰蛋白酶-1 前体的表达从微阵列实验中诱导了 10 倍以上，其 QPCR 验证在 28 天的 100ppb 组中一致，并显示出显著诱导（p<0.05）。总的来说，鼻上皮的病变是本研究中的一个新的重要结果，本研究中鉴定的 TCDD 反应性虹鳟鱼转录本可能为评估环境 TCDD 对虹鳟鱼种群的潜在影响提供新的分子生物标志物。
