College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
Ecotoxicol Environ Saf. 2021 Jan 15;208:111431. doi: 10.1016/j.ecoenv.2020.111431. Epub 2020 Oct 16.
As a common organophosphorus flame retardant, tris (2-butoxyethyl) phosphate (TBOEP) is detected in water environment and aquatic animals extensively. Despite previous researches have reported the developmental toxicity of TBOEP in zebrafish (Danio rerio) larvae, few research focused on its underlying mechanisms. In this study, zebrafish embryos were exposed to 0, 20, 200, 1000 and 2000 µg/L TBOEP from 2 until 120 h post-fertilization (hpf) to determine potential mechanisms of developmental toxicity of this compound. Early developmental stage parameters such as body length, survival rate, hatching rate and heart rate were decreased, while malformation rate was ascended. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was carried out at 12, 24, 72 and 120 hpf to demonstrate alterations in expression of genes of Wnt signaling pathway. The results indicated that axin1 was significantly up-regulated, while β-catenin, pkc and wnt11 were down-regulated. Correlation analysis indicated that expression of these genes was significantly correlated with body length. Furthermore, apoptosis was detected in heart region by acridine orange (AO) staining and terminal deoxynucleotide transferase-mediated deoxy-UTP nick end labeling (TUNEL) assay. In addition, at 120 hpf, occurrence of oxidative stress was observed in zebrafish larvae. Moreover, 6-Bromoindirubin-3'-oxime (BIO)， an activator of Wnt pathway, was found to alleviate the inhibiting effects of TBOEP on zebrafish growth. The overall outcomes offered novel viewpoints in toxic effects of TBOEP, and down-regulating Wnt signaling pathway were able to reveal some potential mechanisms of developmental toxicity of TBOEP in zebrafish larvae.
作为一种常见的有机磷阻燃剂，磷酸三（2-丁氧基乙基）酯（TBOEP）广泛存在于水环境和水生动物中。尽管先前的研究已经报道了 TBOEP 对斑马鱼（Danio rerio）幼虫的发育毒性，但很少有研究关注其潜在的机制。在这项研究中，从受精后 2 小时到 120 小时（hpf），将斑马鱼胚胎暴露于 0、20、200、1000 和 2000µg/L 的 TBOEP 中，以确定该化合物发育毒性的潜在机制。早期发育阶段的参数，如体长、存活率、孵化率和心率降低，而畸形率升高。在 12、24、72 和 120 hpf 时进行定量逆转录聚合酶链反应（qRT-PCR）测定，以证明 Wnt 信号通路基因表达的变化。结果表明，axin1 显著上调，而β-catenin、pkc 和 wnt11 下调。相关性分析表明，这些基因的表达与体长显著相关。此外，通过吖啶橙（AO）染色和末端脱氧核苷酸转移酶介导的脱氧-UTP 缺口末端标记（TUNEL）检测，在心脏区域检测到凋亡。此外，在 120 hpf 时，在斑马鱼幼虫中观察到氧化应激的发生。此外，Wnt 通路的激活剂 6-溴靛红-3'-肟（BIO）被发现减轻了 TBOEP 对斑马鱼生长的抑制作用。总的来说，这些结果为 TBOEP 的毒性作用提供了新的观点，而下调 Wnt 信号通路能够揭示 TBOEP 对斑马鱼幼虫发育毒性的一些潜在机制。
