亚致死性浓度的二噁英在斑马鱼胚胎中所致的毒性反应

[目的]观察亚致死性浓度的二噁英（TCDD）对斑马鱼胚胎发育的毒性作用。[方法]将72hpf（受精后小时）斑马鱼胚胎暴露于渐升的TCDD亚致死性浓度下，观察累积死亡率、心功能及颌软骨发育的变化，与对照组比较。[结果]10pg／ml及25pg／ml的TCDD浓度所导致的两周内的累积死亡率与对照组类似。然而在胚胎内这两种浓度的TCDD均能导致急性及亚急性心脏毒性。暴露在这两种浓度TCDD下与对照组相比，在毒物处理后的12h、1d、2d及1周后胚胎均表现出心每搏输出量及心输出量的显著降低。最显著的发现是72hpf胚胎在10pg／ml的TCDD处理后1周表现出显著的每搏输出量及心输出量降低，伴轻微的心包积液。[结果]该研究表明较低浓度的二噁英污染对野生鱼类能造成威胁，而亚致死性浓度的TCDD对胚胎的颌骨发育无影响。

Toxic Responses of Zebrafish Embryos to Sub-lethal Concentrations of TCDD Exposure

[Objective] To investigate the toxic responses of zebrafish embryos to sub-lethal concentrations of TCDD exposure. [Methods] 72 hpf zebrafish embryos was exposed in gradient concentrations of TCDD （DMSO for control）, the accumulated mortality rates （AMR）, cardiovascular function and jaw development were observed. [Results] At 10 pg/ml and 25 pg/ml TCDD concentrations, the AMR of these embryos were similar to DMSO control in 2 weeks,while the two concentrations leaded to acute and sub-acute cardiac toxicity. The stroke volume （SV） and cardiac output （CO） of these embryos exposed to the two concentrations were significantly reduced compared to DMSO control at 12 hour, 1 day,2 day and 1 week. The most striking finding was that embryos exposed to 10 pg/ml of TCDD at 72 hpf for 1 week exhibited reduced SV,reduced CO and mild pericardial edema. [Conclusion] ：This study suggested that low levels of dioxin contamination may constitute a threat to wild fish species. However,embryonic jaw development seemed not to be affected by sub-lethal dosages of TCDD exposure.