Systemic and behavioral effects of intranasal administration of silver nanoparticles

Abstract

Use of silver nanoparticles (AgNPs) for their antimicrobial properties is widespread. Much of the previous work on the toxicity of AgNPs has been conducted in vitro or following oral or intravenous administration in vivo. Intranasal (IN) instillation of AgNPs mimics inhalation exposure and allows further exploration of the toxicity of these particles via respiratory tract exposure. The present study involved 1) single-dose exposures to assess tissue distribution and toxicity and 2) repeated exposures to assess behavioral effects of IN AgNP exposure (nominally uncoated 25 nm AgNP). AgNP deposition was localized in the liver, gut-associated lymphoid tissue, and brain. Decrease cellularity in spleen follicles was observed in treated mice, along with changes in cell number and populations in the spleen. The splenic GSH:GSSG ratio was also reduced following AgNP exposure. Expression of the oxidative stress-responsive gene Hmox1 was elevated in the hippocampus, but not cortex of treated mice, as was the level of HMOX1 protein. Mice receiving 7 days of IN exposure to 50 mg/kg AgNPs exhibited similar learning- and memory-related behaviors to control mice, except that treated mice spent significantly less time in the target quadrant of the Morris Water Maze during the acquisition phase probe trial. These findings indicate systemic distribution and toxicity following IN administration of AgNPs.

Silver nanoparticles inhaled during pregnancy reach and affect the placenta and the foetus

“…In the present study, we observed the presence of silver containing particles in lungs and in tissues beyond the air-blood barrier, both in the 1h/d and 4h/d exposure group. Not surprisingly, nanoparticles were identified in liver and spleen of both 1h/d and 4h/d exposure groups by TEM associated to EDX and sp ICP-MS analysis, as previously reported by others (Davenport et al 2015, Gosens et al 2016, Lebedovà et al 2016. Importantly, our analysis also allowed identifying for the first time silver containing nanoparticles in the placenta after maternal inhalation exposure.…”

Is Neurotoxicity of Metallic Nanoparticles the Cascades of Oxidative Stress?

“…Ag NPs up-regulated heme oxygenase-1 (HO-1) expression at both the gene and protein levels in the hippocampus, but not in the cortex, after mice were exposed through intranasal instillation [ 73 ]. Another study using microarray analyses [ 74 ] found that, after mice were treated with Ag particles (25 nm), the expression of 18 genes in the caudate nucleus, 14 in the frontal cortex, and 29 in the hippocampal area were altered.…”

Silver nanoparticles: Electron transfer, reactive oxygen species, oxidative stress, beneficial and toxicological effects. Mini review

“…A study involving mice exposed to AgNPs by intranasal instillation showed, upregulated heme oxygenase‐1 expression at both gene and protein levels in the hippocampus and not in the cortex (Davenport et al, ). A related study with rat brain also revealed gene expression in the cortex and hippocampus were altered due to OS caused by AgNPs (Huang, Hsiao, Lin, Wang, & Huang, ; Rahman et al, ).…”