铜及其与四环素的联合暴露对斑马鱼胚胎的毒性效应

近年来工业和养殖业中铜和四环素的滥用,导致了一定的水环境污染问题。为探究铜与四环素对水生生物的毒害作用,选择斑马鱼作为受试生物,研究了铜及其与四环素的联合暴露对斑马鱼胚胎的毒性效应,并进一步探索了其可能的致毒机制。结果表明：铜在低浓度下（10%致死浓度LC10=2.5 μg?L-1,10%效应浓度EC10=0.1 μg?L-1）明显延迟了斑马鱼胚胎的孵化、卵黄囊吸收、头部、鱼鳔和体长等生长指标的发育,同时在心脏区域引起明显细胞凋亡效应。幼鱼体内总铜含量检测结果显示低浓度下铜的生物利用度相对更高。基因表达结果显示环境浓度的铜可能通过影响神经和心脏相关基因的表达引起斑马鱼胚胎的神经发育和心脏发育异常。铜和四环素的联合暴露实验结果表明二者的复合污染类型为拮抗作用,且两者相互作用可以形成络合物。综合以上结论,说明环境浓度的铜可能通过细胞凋亡、分子水平的变化等方式对水生生物的早期生长发育产生危害,如延迟生长发育、神经及心脏发育异常,另外铜可通过和四环素等环境中其他污染物的结合改变铜的生物有效性和毒性。     

Genotoxic effects of binary mixtures of xenoandrogens (tributyltin, triphenyltin) and a xenoestrogen (ethinylestradiol) in a partial life-cycle test with Zebrafish (Danio rerio)

A partial life-cycle test with the model fish Danio rerio was performed in order to evaluate the genotoxic potential of binary mixtures of xenoandrogenic (tributyltin--TBT; triphenyltin--TPT) and an estrogenic compound (ethinylestradiol--EE2). Five days post-fertilisation larvae were diet-exposed to environmental relevant concentrations of TBT and TPT (25 ng/g-100 ng/g), and water-exposed to ethinylestradiol (3.5 ng/L) for a four-month period; binary mixtures of TBT plus EE2 and TPT plus EE2 were run in parallel. The erythrocytic nuclear abnormalities (ENA) assay in circulating erythrocytes was used to evaluate genotoxicity in the end of the four-month exposure period. A significant increase (p<0.05, Kruskall-Wallis non-parametric ANOVA) in ENA frequency, in comparison with control animals, was observed in those animals exposed to TBT and TPT (the highest doses only), and to EE2 and the binary mixtures, although neither synergistic nor additive effects of the tested compounds were evident. Overall, the results clearly indicate that chronic exposure to low levels of TBT, TPT, EE2 and binary mixtures of TBT plus EE2 and TPT plus EE2 are genotoxic to zebrafish, which may suggest that wild fish populations may be under increased DNA damage in areas contaminated by these endocrine disrupting chemicals.     

联苯胺类化合物对斑马鱼胚胎发育毒性的初步研究

应用斑马鱼胚胎发育技术,对4种联苯胺类化合物(联苯胺、3,3'-二甲氧基联苯胺、3,3'-二甲基联苯胺、3,3'-二氯联苯胺)的毒性进行了测定.结果表明,这4种化合物对斑马鱼胚胎发育均有明显抑制作用,可以造成仔鱼畸形甚至死亡,具有特定的最敏感毒理学终点及作用时间;联苯胺苯环上的取代基可以增强联苯胺的亲电作用或亲核作用,从而增强其胚胎毒性,其中尤以卤代产物(3,3'-二氯联苯胺)最为显著.其毒性排列顺序大致为:3,3'-二氯联苯胺>3,3'-二甲基联苯胺>3,3'-二甲氧基联苯胺>联苯胺;4种联苯胺的斑马鱼胚胎毒性数据与lgKow没有显著相关性,推测这4种联苯胺的毒性机理属体内反应型,毒物参与生理代谢.     

Cypermethrin has the potential to induce hepatic oxidative stress, DNA damage and apoptosis in adult zebrafish (Danio rerio)

Cypermethrin (CYP), a widely used Type II pyrethroid pesticide, is one of the most common contaminants in the freshwater aquatic system. We studied the effects of CYP exposure on the induction of hepatic oxidative stress, DNA damage and the alteration of gene expression related to apoptosis in adult zebrafish. Hepatic mRNA levels for the genes encoding antioxidant proteins, such as Cu/Zn-Sod, Mn-Sod, Cat, and Gpx, were significantly upregulated when zebrafish were exposed to various concentrations of CYP for 4 or 8 days. In addition, the main genes related to fatty acid β-oxidation and the mitochondrial genes related to respiration and ATP synthesis were also significantly upregulated after exposure to high concentrations (1 and 3 μg L⁻¹) of CYP for 4 or 8 days. Moreover, in a comet assay of zebrafish hepatocytes, tail DNA, tail length, tail moment and Olive tail moment increased in a concentration-dependent manner. The significant induction (p < 0.01) of all four parameters observed with CYP concentrations of 0.3 μg L⁻¹ or higher suggests that heavy DNA damage was induced even at low levels. Furthermore, several apoptosis- related genes, such as p53, Apaf1 and Cas3, were significantly upregulated after CYP exposure, and Bcl2/Bax expression ratio decreased, especially in groups treated with 1 and 3 μg L⁻¹ CYP for 8 days. Taken together, our results suggested that CYP has the potential to induce hepatic oxidative stress, DNA damage and apoptosis in zebrafish. This information will be helpful in fully understanding the mechanism of aquatic toxicology induced by CYP in fish.     

水体中3种磺胺类药物对斑马鱼的生态毒性效应

采用斑马鱼作为模式动物,针对斑马鱼的代谢能力,进行3种磺胺类药物(磺胺甲恶唑,磺胺嘧啶,磺胺二甲嘧啶)的暴露实验。实验选取谷胱甘肽s-转移酶(GST)和丙二醛(MDA)含量作为评判斑马鱼代谢能力的指标。在实验过程中,随着暴露时间的改变,GST活性和MDA含量都呈现出不同的变化。在实验前3 d,GST酶活性在不同浓度下都呈现出显著增长。但是MDA的含量在第1天达到顶峰,随后都呈现出下降趋势。由结果可得,MDA含量指标对磺胺类药物的毒性更加敏感,其指示作用更优于GST活性指标。同时,实验结果中可以看出,在磺胺嘧啶作用下的GST酶活性和MDA含量都呈现更加明显的变化,因此实验推断磺胺嘧啶会对水环境具有更潜在的危害。     

评估斑马鱼胚胎毒性试验在农药危害筛选中的应用

考虑到人类社会中大量使用化学物质，想要准确有效地评估这些化学物质对人类和生态受体的潜在风险，研发有效的手段和方法是至关重要的。鱼胚胎急性毒性试验是其中一种工具，已表现出与幼鱼急性毒性标准试验的预测结果高度吻合，而幼鱼试验对资源消耗更多。然而，也有证据表明，对于某些类型的化学物质，包括神经毒素，鱼类胚胎的敏感性低于幼鱼。本文利用已发表的斑马鱼胚胎毒性数据，与3种常用检测用鱼幼鱼(虹鳟鱼、蓝鳃太阳鱼、羊鲷)的半致死浓度50%(LC₅₀)数据进行比较，研究了鱼类胚胎对农药危害评估的效用。在将农药视为单因素的情况下，斑马鱼胚胎和幼鱼毒性数据相关性较差，差异显著(r²=0.28；p2=0.64；p 精选自Glaberman, S., Padilla, S. and Barron, M. G. (2017), Evaluating the zebrafish embryo toxicity test for pesticide hazard screening. Environmental Toxicology and Chemistry, 36: 1221–1226. doi: 10.1002/etc.3641
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3641/full
     

Benzo[a]pyrene exposure influences the cardiac development and the expression of cardiovascular relative genes in zebrafish (Danio rerio) embryos

It is reported that the most abundant polycyclic aromatic hydrocarbons (PAHs) in weathered crude oils are cardiotoxic. However, the action mechanism of PAHs on vertebrate cardiovascular development and disease is unclear. In the present study, the cardiac morphology and functioning of zebrafish embryos exposed to benzo[a]pyrene [B(a)P], as a high-ring PAHs, for 72 h were observed and determined. The results showed that B(a)P exposure resulted in cardiac developmental defects in zebrafish embryos. Significant changes in expression level of multiple genes potentially critical for regulating the B(a)P-induced cardiovascular developmental defects were also found. A gene network regulating cardiac development perturbed by B(a)P exposure was identified and established by computational analysis and employment of some databases. The information from the network could provide a clue for further mechanistic studies explaining molecular events regulating B(a)P-mediated cardiovascular defects and consequences.     

Phenanthrene exposure produces cardiac defects during embryo development of zebrafish (Danio rerio) through activation of MMP-9

Phenanthrene (Phe) is one of the most abundant polycyclic aromatic hydrocarbons in the aquatic environment as a result of human activities. It is widely accepted that Phe has cardiotoxic effects. Even so, knowledge concerning the mechanism(s) of cardiac development toxicity is still limited. In this study, we exposed zebrafish embryos to environmentally relevant concentrations of Phe and then investigated its cardiotoxic effects and the mechanism(s) involved. Some cardiac morphogenetic defects, which was characterized by an abnormally looped and enlarged heart, dilated and thinner ventricular wall, and increased interstitial fibrosis, were observed in the Phe treated groups. The mRNA and protein expression levels of matrix metalloproteinase-9 (MMP-9), as well as the MMP-9 activity, were induced. Moreover, during co-treatment of the zebrafish embryos with MMP-9 inhibitor, the cardiac defects caused by Phe were attenuated. In addition, Phe exposure led to an up-regulation of transforming growth factor β (TGF-β), which plays a crucial role in mediating cardiac fibrosis. Taken together, our data indicated that the exposure to Phe of zebrafish embryos disrupted normal cardiac development, and that the cardiac defects induced by Phe were mediated by the MMP-9, while TGF-β was also involved in these cardiac defects.     

Efficacy assessment of peracetic acid in the removal of synthetic 17α-ethinyl estradiol contraceptive hormone in wastewater

Increasing concerns have been raised on endocrine disrupting chemicals like the sex hormone 17α-ethinylestradiol (EE2), the more since traditional wastewater (WW) treatments appear to be ineffective for their removal. The efficacy of the relatively novel disinfectant peracetic acid (PAA) in EE2 removal was evaluated, as well as its potential effects on WW quality parameters. The treatments tested for EE2 removal were also evaluated in terms of toxicity, through the determination of biochemical responses (antioxidant enzymes, lipid peroxidation and vitellogenin induction) using zebrafish (Danio rerio) as a biological model. PAA contact times less than 20 min appeared insufficient regardless of the PAA dose tested, but a 100% EE2 removal was attained at a PAA concentration of 15 mg/L with a contact time of 20 min. Total suspended solids, chemical oxygen demand and pH in PAA treatments remained well within levels set in European legislation for WW discharge. EE2 induced significant increased vitellogenin (VTG) levels in both female and male fish, indicating increased estrogenic activity, especially in males suggesting an endocrine disruption effect. With the addition of PAA (15 mg/L), however, VTG levels in both sexes returned to control values. Although this PAA treatment showed increased levels of the antioxidant enzyme catalase, the lipid peroxidation levels were similar or even lower than in controls. Overall the results suggest that the use of PAA appears a promising way forward as a less toxic alternative to chlorine disinfection with high efficiency in the removal of EDC like EE2.     

斑马鱼在环境保护中的应用

斑马鱼易饲养、易管理,体外受精和体外发育,可常年产卵、孵化,且胚胎透明,因此早期作为模型动物广泛用于生物学研究中.近年来,随着水环境问题日益突出,迫切需要有效、全面的环境监测手段.斑马鱼或其转基因品种不失为水环境监测的首选生物.因为它们对各类水环境污染十分敏感,可实时检测进入水环境的污染物.文章对斑马鱼在环境激素、水质...