Kinetics of Silver Accumulation in Tissues of Laboratory Mice after Long-Term Oral Administration of Silver Nanoparticles

Abstract

Since ancient times, silver has been known for its pronounced bactericidal, antiviral and fungicidal properties. Currently, nanoparticles of this metal are widely used in the food, light and pharmaceutical industries, as well as in medicine. Silver in any form can have a toxic effect not only on pathogens, but also on healthy cells. The biological activity and bioavailability of silver preparations depend on the degree of their solubility in water. In addition, the maximum permissible concentration of soluble forms of silver is an order of magnitude lower than that of insoluble forms. This makes nanoparticles of silver with a hydrophilic coating that form stable colloidal solutions in aqueous media potentially unsafe objects. In this work, we studied the kinetics of the accumulation of silver nanoparticles with an average size of 34 ± 5 nm stabilized with polyvinylpyrrolidone in the organs of laboratory C57Bl/6 mice. The administration of nanoparticles was carried out orally for 30, 60, 120 and 180 days at the dose of 50 µg/day/animal. All the mice developed and gained weight normally during the experiment. No adverse effects were observed. Determination of the silver content in biological tissues of mammals was accomplished by neutron activation analysis. The masses and concentrations of silver in the brain and its different sections (hippocampus, cerebellum, cortex and remnants), as well as in the lungs, testes, liver, blood, kidneys, spleen and heart, were determined. The injection times at which the accumulation curves reached saturation were established. An extremely high accumulation of silver in the testes was shown at 120 days of administration, and a significant accumulation of silver in the lungs and brain was observed. The accumulation of silver in all parts of the brain except the cortex was significant, and its trend was similar to that in the whole brain.

Effect of Different Forms of Silver on Biological Objects

“…Consequently, silver displays a higher affinity for the liver, kidney, and spleen during the first days or even hours of exposure. However, as a result of its slow excretion, silver accumulates in the brain, lungs, and testicles and passes through blood-tissue barriers [74], as the time of exposure increases.…”

Relationships between Effects of Ag Nanoparticles and Ag Salt on Behavioral and Cognitive Functions of Mice and Ageing

“…We used AgNPs Argovit-S as a xenobiotic N 1 and Ag+ as a xenobiotic N 2. We have certain experience to work with Argovit-S [9,12,16,23]. The nanoparticles are stabilized with hydrophilic coating as polyvinylpyrrolidone.…”

“…It is known that Ag NPs and Ag in ionic form may accumulate in different tissues [9][10][11], for instance in brain [12]. Certainly, accumulation of Ag in brain is not a sufficient condition for influence on cognitive functions due to the necessity of taking into account more complicated bounds between systems and tissue and neurovisceral integration itself [13].…”

“…First of all, it is important to establish less harmful silver compound. The used AgNPs have been already fully described in other our works in part of their biokinetics as well [9,23]. We choose Ag citrate (Ag+) as highly biocompatible and in the same time rather accessible Ag salt.…”

Putative adverse outcome pathway for silver nanoparticle toxicity on male reproductive system: A literature review

“…According to European Commission Scienti c Committees, the main target organs for Ag NP in the human body are the spleen, liver, and kidney, with less distribution to other organs ( 14). There are studies that recorded high levels of silver accumulation in the brain and testicles (14,25,(27)(28)(29)(30)(31), although the signi cance for toxicity is unknown (14). In 2018, the Scienti c Committee on Consumer Safety (SCCS) of the European Commission recommended to collect information on the reproductive toxicity of Ag NPs (32).…”