Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada.
Aquat Toxicol. 2009 Dec 13;95(4):299-306. doi: 10.1016/j.aquatox.2009.03.009. Epub 2009 Apr 5.
Developmental exposure to aryl hydrocarbon receptor (AhR) agonists in fish causes severe defects in the cardiovascular system. However, the effects of acute AhR agonist exposure on the adult fish cardiovascular system are not clear. We hypothesized that AhR-mediated changes in adult vascular tissue gene expression would differ from that of hepatic tissue. Therefore, zebrafish (Danio rerio) were intraperitoneally injected with the AhR agonists benzo-a-pyrene (BaP; 1mg/kg) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 20microg/kg) alone and in combination with the AhR antagonists resveratrol (Res; 10mg/kg) or alpha-naphthoflavone (ANF; 50mg/kg). Hepatic and mesenteric artery cytochrome P450 enzyme (subtypes 1A, 1B1, 1C1, and 1C2) and cyclooxygenase enzyme (subtypes 1, 2a, and 2b) mRNA expression was quantified using real-time reverse transcriptase PCR. TCDD exposure significantly increased (p<or=0.05 in Tukey's posteriori test after 1-way ANOVA; n=4-6/group) CYP1A, CYP1C1, and COX-2b mRNA expression in hepatic tissue (105+/-21, 12+/-2, and 2+/-0.3 fold-increase, mean+/-SEM respectively). TCDD also increased CYP1A, CYP1B1, CYP1C1, CYP1C2, and COX-1 mRNA expression in mesenteric artery (121+/-23, 5+/-1, 28+/-6, 7+/-1, and 3+/-0.3, respectively). Importantly, while BaP exposure elicited no significant alterations in hepatic CYP mRNA expression, it increased COX-1 and COX-2b in liver tissues (3+/-1 and 2+/-0.1, respectively), as well as CYP1A, CYP1B1, CYP1C1, CYP1C2, and COX-1 expression in mesenteric artery (2+/-0.3, 4+/-0.3, 5+/-1, 5+/-1, and 2+/-0.3, respectively). Resveratrol was able to antagonize TCDD-induced CYP1C2 in mesenteric artery but was without effect in all other treatments in both liver and mesenteric artery. In contrast, ANF antagonized TCDD and BaP-induced COX-2b and TCDD-induced CYP1C1 expression increases, as well as reduced baseline CYP1B1 and COX-2a expression in liver, while failing to affect BaP and TCDD-induced hepatic CYP1A increases. However, in mesenteric artery, ANF alone acted instead as an agonist to increase expression of CYP1A, CYP1B1, CYP1C1, CYP1C2, COX-2a and COX-2b. Thus, there are important differences in response to both AhR agonists and antagonists between liver and mesenteric artery in adult zebrafish. The vascular-specific changes in gene expression will be linked to future studies examining alterations in cardiovascular function produced by acute AhR agonist exposure in adult fish.
发育过程中接触芳烃受体 (AhR) 激动剂会导致鱼类心血管系统严重缺陷。然而，急性 AhR 激动剂暴露对成年鱼类心血管系统的影响尚不清楚。我们假设 AhR 介导的成年血管组织基因表达的变化将不同于肝脏组织。因此，我们将斑马鱼 (Danio rerio) 腹膜内注射 AhR 激动剂苯并 (a) 芘 (BaP; 1mg/kg) 或 2,3,7,8-四氯二苯并二恶英 (TCDD; 20μg/kg) 单独和联合使用 AhR 拮抗剂白藜芦醇 (Res; 10mg/kg) 或 α-萘黄酮 (ANF; 50mg/kg)。使用实时逆转录聚合酶链反应定量检测肝和肠系膜动脉细胞色素 P450 酶 (亚型 1A、1B1、1C1 和 1C2) 和环氧化酶酶 (亚型 1、2a 和 2b) mRNA 表达。TCDD 暴露显著增加 (Tukey 氏事后检验，单因素方差分析后 p<0.05;n=4-6/组) 肝组织中 CYP1A、CYP1C1 和 COX-2b mRNA 的表达 (分别增加 105+/-21、12+/-2 和 2+/-0.3 倍，均值+/-SEM)。TCDD 还增加了肠系膜动脉中 CYP1A、CYP1B1、CYP1C1、CYP1C2 和 COX-1 mRNA 的表达 (分别为 121+/-23、5+/-1、28+/-6、7+/-1 和 3+/-0.3)。重要的是，虽然 BaP 暴露对肝 CYP mRNA 表达没有显著改变，但它增加了肝组织中的 COX-1 和 COX-2b (分别为 3+/-1 和 2+/-0.1)，以及肠系膜动脉中的 CYP1A、CYP1B1、CYP1C1、CYP1C2 和 COX-1 表达 (分别为 2+/-0.3、4+/-0.3、5+/-1、5+/-1 和 2+/-0.3)。白藜芦醇能够拮抗 TCDD 诱导的肠系膜动脉中 CYP1C2，但在肝和肠系膜动脉的所有其他处理中均无作用。相比之下，ANF 拮抗 TCDD 和 BaP 诱导的 COX-2b 和 TCDD 诱导的 CYP1C1 表达增加，以及降低肝中 CYP1B1 和 COX-2a 的基础表达，而不影响 BaP 和 TCDD 诱导的肝 CYP1A 增加。然而，在肠系膜动脉中，ANF 本身作为激动剂，增加了 CYP1A、CYP1B1、CYP1C1、CYP1C2、COX-2a 和 COX-2b 的表达。因此，AhR 激动剂和拮抗剂在成年斑马鱼的肝脏和肠系膜动脉之间存在重要的差异。血管组织基因表达的这些变化将与未来研究中急性 AhR 激动剂暴露对成年鱼类心血管功能改变相关联。
