• Low Dose Effects of Green Synthesized Silver Nanoparticles on Amyloid β-induced neurotoxicity in rats
  • Sepideh Tarbali,1,* Saeed Karami Mehrian,2
    1. Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
    2. Department of Biology, Faculty of Sciences, University of Razi, Kermanshah, Iran


  • Introduction: The application of nanotechnology for treatment of Alzheimer's disease (AD), as a progressive cognitive disorder has become a striking topic in researches. One of the contributing factors in the pathophysiology of AD is the imbalance in redox state of neuronal cells. Human cells exposure to silver nanoparticles (SNPs) is inevitable due to broad use of them in food and drug industries. As well as, nowadays they are considered as an attractive therapeutic opportunity for human diseases. While numerous studies have demonstrated the toxicity of SNPs on neuronal cells, their anti-inflammatory, and restrictive effect on neurotoxicity have also been reported. Meanwhile, the green synthesis method (using plants’ extracts) is a strategy to diminish the toxicity of SNPs.
  • Methods: In this regard, we assessed the effects of green synthesis of SNPs via leaf aqueous extract of M. communis plant in an animal model of cognitive decline. Induction of cognitive impairment was performed by intracerebroventricular (ICV) injection of amyloid beta (Aβ) in male rats. The 0.1 ppm of Green-SNPs were prepared in deionized water and dispersed with an ultrasonic shaker for 20 min before each injection. Animals were dedicated to 5 groups by chance (n=10): 1) Intact group: remained intact during the experiments; 2) Sham group received intra-ICV injection of saline; 3) Green-SNPs group received intra-ICV injection of Green-SNPs; 4) Aβ group which received intra-ICV injection of Aβ (20 μg/10μl); 5) Aβ+Green-SNPs group which received Green-SNPs, one hour after intra-ICV injection of Aβ. We evaluated the behavioral indices using y maze, novel object recognition, elevated plus maze and passive avoidance memory tests. The redox status assessment was performed via malondialdehyde and superoxide dismutase activity analysis in hippocampus tissue.
  • Results: We observed a cognitive impairment, anxiety behavior, an increase in lipid peroxidation and a reduction in superoxide dismutase activity in the Aβ -injected rats. Administration of Green- SNPs (at doses the 0.1 ppm) significantly improved behavioral indices. It also, decreased lipid peroxidation and increased superoxide dismutase activity.
  • Conclusion: Current findings suggested that potential ability of sub-toxic doses of Green-SNPs on relieving memory impairment in an animal model of AD. The observed positive role of Green-SNPs on behavioral indices may be due to the antioxidative effects of Green-SNPs. Understanding the biological effects of Green-SNPs, can be used to make future safe classes of SNPs or may pave the way to new therapeutic approaches in brain diseases.
  • Keywords: Green silver nano particles, Alzheimer's disease, Hippocampus, Redox status.