Trace metal ions such as cadmium (Cd²⁺) and trace organics typified by 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) are common co-contaminants in the environment and cause toxic effects in aquatic organisms that pose serious health risks. We studied the effects of Cd²⁺ on the regulation of cytochrome P450 1A1 (cyp1a1) gene-induction by TCDD using zebrafish embryos and larvae and adult zebrafish tissues. Our results showed that TCDD induced the cyp1a1 gene in all developmental stages and tissues of zebrafish, and the induction was higher in females than males. However, for the upstream genes (ahr2 and arnt2b) that mediate cyp1a1 gene induction in the zebrafish liver cell line was not induced by TCDD similar to the pattern of cyp1a1 in all investigated groups. After co-treatment with Cd²⁺, induction of the aryl hydrocarbon receptor pathway by TCDD was inhibited in the zebrafish larvae and the livers, intestines, kidneys and gills of adult zebrafish, but not in the embryos or brains of adult zebrafish, indicating that the toxicological effects of Cd²⁺ on TCDD are dependent on the developmental stages and tissue types. The present study confirms that Cd²⁺ blocks the TCDD-induced cyp1a1 gene in vivo but emphasizes that the effects are specific to the developmental stage, type of tissue and sex. The combined effects of Cd²⁺ and TCDD must be taken into consideration together with these parameters to accurately predict and assess cadmium and TCDD-induced toxicity in fish and carcinogenesis in animals in general.

痕量金属离子，例如镉（Cd ²⁺）和痕量有机物，以2,3,7,8-四氯二苯并-对-二恶英（TCDD）为代表，是环境中的常见污染物，会对造成严重危害的水生生物产生毒性作用。健康风险。我们研究了Cd ²⁺对使用斑马鱼胚胎和幼虫以及成年斑马鱼组织的TCDD调节细胞色素P450 1A1（cyp1a1）基因诱导的影响。我们的结果表明，TCDD在斑马鱼的所有发育阶段和组织中均诱导了cyp1a1基因，雌性的诱导率高于雄性。但是，对于介导cyp1a1的上游基因（ahr2和arnt2b）在所有研究组中，类似于cyp1a1的模式，TCDD均未诱导斑马鱼肝细胞系中的基因诱导。与Cd ²⁺共同处理后，TCDD诱导的芳基烃受体途径在成年斑马鱼的斑马鱼幼虫和肝脏，肠，肾和g中被抑制，而在成年斑马鱼的胚胎或脑中则没有被抑制。 Cd ²⁺对TCDD的毒理作用取决于发育阶段和组织类型。本研究证实Cd ²⁺在体内能阻断TCDD诱导的cyp1a1基因但要强调的是，这种效应是特定于发育阶段，组织类型和性别的。必须将Cd ²⁺和TCDD的综合作用与这些参数一起考虑，以准确预测和评估镉和TCDD诱导的鱼类毒性以及一般动物的致癌作用。