多壁碳纳米管分阶段暴露对热带爪蛙胚胎发育的毒性

近年来，碳纳米管（CNTs）的产量和使用量不断增大，提高了其释放到环境中的可能性.尽管碳纳米管的水生生态毒性有所报道，但对两栖动物胚胎的发育毒性研究仍比较少.本研究采用分阶段暴露的方式，以热带爪蛙胚胎的死亡率、孵化率、畸形率、畸形类型、心率、体长等作为毒性评价指标，研究不同浓度多壁碳纳米管（25、50 mg·L^-1）对爪蛙胚胎发育的胚胎毒性与敏感窗口.结果显示，多壁碳纳米管可导致爪蛙胚胎死亡率升高，孵化率降低，但对其心率、体长没有显著性影响（p>0.05）.产生的畸形类型包括心腔水肿、脊索弯曲、泄殖腔畸形、眼睛畸形等，其中，心腔水肿占的比例最大为28.7%.另外，根据死亡率、孵化率、畸形率等指标综合评价爪蛙胚胎对多壁碳纳米管的敏感程度，由强到弱的顺序依次是：原肠胚期、囊胚期、神经胚期、尾芽期.研究表明，浓度为25 mg·L^-1和50 mg·L^-1的多壁碳纳米管对热带爪蛙胚胎发育具有一定的毒性作用，其作用机理与胚胎卵膜粘附碳纳米管有间接关系，研究结果可为合理评价碳纳米管对水生生物胚胎的影响提供一定的理论参考.

Developmental toxic of multi-walled carbon nanotubes to Xenopus tropicalis embryos of different stages

With the production and use of carbon nanotubes (CNTs) increasing, the ecotoxicty of the released CNTs on various aquatic organisms worth concerning, but unfortunately little information is available, especially on amphibian embryos. In this study, Xenopus tropicalis embryos at different growth stages were exposured to multi-walled carbon nanotubes (MWCNTs) with different concentrations (25 mg·L^-1, 50 mg·L^-1). Several parameters were recorded including mortality rate, hatching rate, malformation rate, malformation type, heartbeat rate, and body length. The results showed that the exposure of MWCNTs increased the mortality of embryos and reduced their hatching rate significantly (p<0.05), but no obvious effect on heart rate and body length (p>0.05). The main types of malformations included cardiac edema, spinal cord bending, cloaca deformity, eyes deformity etc. The cardiac edema among of them accounted for the largest proportion (28.7%). Moreover, the embryos of different growth stages were sensitive to MWCNTs in the turn from strong to weak as gastrula stage, blastocyst stage, neural stage and tail bud stage. Therefore, MWCNTs have toxic effect on embryo development owing to damage from the adhesion of MWCNTs to embryonic egg membrane, which has important implication to evaluation of MWCNTs on aquatic animal embryos.