PUBLICATION

How toxic is a non-toxic nanomaterial: Behaviour as an indicator of effect in Danio rerio exposed to nanogold

Authors
Botha, T.L., Brand, S.J., Ikenaka, Y., Nakayama, S.M.M., Ishizuka, M., Wepener, V.
ID
ZDB-PUB-190907-8
Date
2019
Source
Aquatic toxicology (Amsterdam, Netherlands)   215: 105287 (Journal)
Registered Authors
Keywords
Adverse outcomes pathway, Nanogold, Swimming behaviour, Zebrafish
MeSH Terms
  • Biomarkers/metabolism
  • Animals
  • Muscles/drug effects
  • Metal Nanoparticles/toxicity*
  • Metal Nanoparticles/ultrastructure
  • Water Pollutants, Chemical/toxicity
  • Liver/drug effects
  • Liver/metabolism
  • Swimming
  • Multigene Family
  • Behavior, Animal/drug effects*
  • Gold/toxicity*
  • Zebrafish/genetics
  • Zebrafish/physiology*
PubMed
31491706 Full text @ Aquat. Toxicol.
Abstract
Gold nanoparticles are used as drug delivery vectors based on the assumption that they have low toxicity. Literature has, however, produced conflicting results over the last few years. As such, this study aimed to investigate the toxicological effects of nanogold (nAu) on several indicators that range from subcellular to whole-organism level. Gene regulation, changes in oxidative stress biomarkers and swimming performance were assessed in Danio rerio (zebrafish) following exposures to nAu. Adult zebrafish were exposed in vivo to nAu for 96 h and swimming performance measured post-exposure. Liver tissue was collected for DNA microarray and Real-Time Polymerase Chain Reactions (RT-PCR) analyses to determine changes in gene expression (catalase, superoxide dismutase and metallothioneins) and protein biomarker analyses (catalase, superoxide dismutase, acetylcholine esterase, malondialdehyde, cellular energy allocation and metallothionein) were performed on whole-body samples. Swimming behaviour was assessed in 1.1 L Tecniplast™ tanks for a period of six hours and videos were analysed using Noldus EthoVision software. Critical swimming speed was measured in a Loligo® swimming tunnel. The DNA microarray revealed that fish exposed to 20 mg/L differed most from the control group. At 20 mg/L there was a significant increase in gene expression for all genes analysed but this didn't translate to significant responses in protein biomarker levels except for an increase in protein carbonyl formation. The behaviour results demonstrated significant changes in distance moved, swimming speed, acceleration bouts, zone alterations and time spent within the top zone - responses that are usually observed in fish responding to toxicological stress. Furthermore, the critical swimming speed of exposed fish was decreased significantly compared to the control. Since swimming performance and social interaction among zebrafish is essential to their survival, whole-organism behaviour that suggests a toxicological response after exposure to nAu is in agreement with the genetic responses measured in this study.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping