Toxicity of internalized laser generated pure silver nanoparticles to the isolated rat hippocampus cells

Toxicol Ind Health. 2017 Jul;33(7):555-563. doi: 10.1177/0748233717690992. Epub 2017 Feb 15.

Abstract

Silver nanoparticles (AgNPs) are the most commonly used nanoparticles (NPs) in medicine, industry and cosmetics. They are generally considered as biocompatible. However, contradictory reports on their biosafety render them difficult to accept as 'safe'. In this study, we evaluated the neurotoxicity of direct AgNP treatment in rat hippocampal slices. We produced pure uncoated AgNPs by a pulsed laser ablation method. NP characterization was performed by Ultraviolet (UV) visible spectrophotometer, scanning electron microscope, transmission electron microscope (TEM) and energy-dispersive X-ray spectroscopy. Rat hippocampal slices were treated with AgNPs for an hour. AgNP exposure of hippocampal tissue resulted in a significant decrease in cell survival in a dose-dependent manner. Our TEM results showed that AgNPs were distributed in the extracellular matrix and were taken into the cytoplasm of the neurons. Moreover, we found that only larger AgNPs were taken into the neurons via phagocytosis. This study showed that the pure AgNPs produced by laser ablation are toxic to the neural tissue. We also found that neurons internalized only the large NPs by phagocytosis which seems to be the major mechanism in AgNP neurotoxicity.

Keywords: Laser ablation; classical endocytosis; hippocampus; internalization of nanoparticles; neurodegenerative disease; silver nanoparticles.

MeSH terms

  • Animals
  • Cell Survival / drug effects
  • Dose-Response Relationship, Drug
  • Hippocampus / cytology
  • Hippocampus / drug effects*
  • Male
  • Metal Nanoparticles / toxicity*
  • Neurons / drug effects*
  • Phagocytosis
  • Rats
  • Rats, Wistar
  • Silver / toxicity*
  • Spectrometry, X-Ray Emission

Substances

  • Silver