The emerging flame retardants pentabromobenzene (PBB) has been frequently detected in recent years and may pose exposure risks to wild animals and human beings. In this study, the inflation of posterior swim bladder of zebrafish larvae was used as an endpoint to study the developmental toxicity and putative mechanisms associated with PBB toxicity. Our results showed that embryonic exposure to PBB could significantly inhibit the inflation of posterior swim bladders. Reduced T3 levels and transcriptional changes of crh and pomc were observed in PBB treated zebrafish larvae at 120 hpf. However, key regulators of thyroid and adrenocortical system involved in the synthesis (tsh), biological conversion (ugt1ab, dio2) and functional regulation (trα, trβ, gr) showed no significant changes. Further data revealed that prlra was the only gene that was altered among the detected genes at 96 h post fertilization (hpf). At 120 hpf, the morphology of swim bladder indicated deflation in treatments at 0.25 μM and higher. In addition, the mRNA levels of anxa5, prlra, prlrb, atp1b2 and slc12a10 were all significantly changed at 120 hpf. Taken together, we suppose that embryonic exposure to PBB inhibited the inflation of swim bladder in zebrafish probably via prlra mediated pathways. The observed changes of thyroid and adrenocortical parameters might be indirect effects evoked by PBB exposure. Overall, our results provide important data and indications for future toxicological study and risk assessment of the emerging flame retardants PBB.

新兴的阻燃剂五溴苯（PBB）近年来已被频繁检测到，并可能对野生动物和人类造成危害。在这项研究中，斑马鱼幼虫后游泳膀胱的充气被用作研究PBB毒性的发育毒性和推测机制的终点。我们的结果表明，多溴联苯的胚胎接触可显着抑制后游泳膀胱的膨胀。在120 hpf下，多溴联苯处理的斑马鱼幼虫的T3含量降低，crh和pomc的转录也降低。但是，甲状腺和肾上腺皮质系统的关键调节因子参与了合成（tsh），生物转化（ugt1ab，dio2）和功能调节（trα，trβ，gr）均无明显变化。进一步的数据表明，prlra是受精后96 h（hpf）中唯一被检测到的基因发生改变的基因。在120 hpf时，游泳膀胱的形态表明在0.25μM及更高浓度的治疗中放气。另外，anxa5，prrra，prrlb，atp1b2和slc12a10的mRNA水平在120 hpf时均发生了显着变化。两者合计，我们认为胚胎暴露于PBB可能通过prlra抑制了斑马鱼中游泳膀胱的膨胀。介导的途径。观察到的甲状腺和肾上腺皮质参数的变化可能是多溴联苯暴露引起的间接影响。总的来说，我们的结果为新兴的阻燃剂PBB的未来毒理学研究和风险评估提供了重要的数据和指示。