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Impact of co-exposure to titanium dioxide nanoparticles and Pb on zebrafish embryos

Author:
Hu, Shengchao, Han, Jian, Yang, Lihua, Li, Sen, Guo, Yongyong, Zhou, Bingsheng, Wu, Hongjuan
Source:
Chemosphere 2019 v.233 pp. 579-589
ISSN:
0045-6535
Subject:
Danio rerio, bioaccumulation, bioavailability, embryo (animal), gene expression regulation, genes, heavy metals, larvae, lead, metallothionein, nanoparticles, swimming, titanium dioxide, toxicity
Abstract:
Complex interactions have been established between nanoparticles (NPs) and heavy metals in real environments. Herein we used zebrafish embryos to investigate the influence of titanium dioxide NPs (n-TiO2) on the uptake, bioconcentration, and depuration, and toxicity of Pb. The formation of n-TiO2–Pb complexes was confirmed in an exposure suspension. An increase in Pb bioconcentration was observed in zebrafish embryos upon co-exposure to n-TiO2 and Pb; moreover, n-TiO2–Pb complexes could be found in the embryos, indicating the bioavailability of NPs. However, there was no difference in the depuration rates of Pb in the presence of n-TiO2. Metallothionein (MT) content was significantly increased upon exposure to Pb alone, and the content significantly increased even further upon co-exposure. A downregulation in the expression levels of the neurodevelopment-related genes gfap, syn2α, and elavl3 was observed in the embryos, and we also noted a reduction in the swimming speed of and the total distance traveled by the larvae. To summarize, our results indicate that n-TiO2 can act as an effective carrier of Pb to enhance its uptake, bioavailability, and toxicity in zebrafish embryos.
Agid:
6461023