摘要:
磷酸三苯酯(triphenyl phosphate,TPP)作为多溴联苯醚类阻燃剂的替代产品,是一类生产和需求量均相当高的有机磷酸酯类阻燃剂,目前已在多种环境介质以及生物体内均有不同程度检出。由于结构和有机磷农药具有相似性,其对生物的神经毒性值得关注。本研究以斑马鱼为实验动物,研究了TPP (5~625 μg·L-1)的胚胎发育毒性和行为毒性,并通过检测乙酰胆碱酯酶活性以及神经系统相关基因的转录水平,探讨其可能的毒性机制。研究发现,TPP可导致斑马鱼胚胎孵化时间延长,体长变短,心率变慢。同时,TPP暴露也可以影响斑马鱼幼鱼在持续光照和明暗周期刺激下的游泳行为,表现为低浓度增加而高浓度降低其游泳速度。而TPP暴露后幼鱼乙酰胆碱酯酶活性以及神经发育相关基因转录水平的变化可能是导致其行为毒性的原因。虽然实验中所设定的暴露浓度高于环境中一般浓度,但TPP在短期暴露中所表现出的胚胎和神经发育毒性表明TPP对于水生生物可能存在一定风险,需要进一步研究加以确认。
Abstract:
Triphenyl phosphate (TPP) belongs to the family of organophosphate flame retardants (OPFRs). Due to the phase-out of some brominated flame retardants, the production and use of TPP has gradually increased as alternatives. TPP is a frequently detected contaminant in the environment and wildlife, and the effects of TPP on the developing nervous system are of concern since OPFRs are structurally similar to organophosphate pesticides. In this study, the zebrafish were employed as experimental animal, and the developmental toxicity of TPP (5~625 μg·L-1) on embryo and the behavioral toxicity on larvae were investigated. Moreover, in order to explore the underlying mechanisms, the activity of acetylcholinesterase (AChE) enzyme and the transcriptional responses of nervous system genes were measured. The results showed that TPP exposure delayed the time to hatching, and decreased the heart rate and body length. Additionally, TPP exposure caused the changes of swimming behaviors of larvae in the free swimming or the dark-light-dark photoperiod stimulation test, and resulted in the increase of swimming speed at low concentration while the decrease at high concentration. The changes of AChE activity and transcriptional responses of nervous system genes might afford the explanation for the behavioral toxicity. Although the exposure concentration of TPP used in this study exceeded the environmental concentration, the developmental toxicity on embryo the behavioral toxicity on larvae after short term exposure demonstrated that TPP might pose a risk to aquatic organism, and deserved more investigations in the future.
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