Toxicity effects evaluation of green synthesized silver nanoparticles on intraperitoneally exposed male Wistar rats

Abstract

Objective: During the last decades, the widespread use of silver nanoparticles (AgNPs) has been considered because of their small size and antimicrobial effects. The main concern about these particles is that they can induce oxidative stress. In this study, the dose-dependent effects of green synthesized silver nanoparticles (Green-AgNPs) were evaluated on adult male rats.

Methods: Animals were injected intraperitoneally (I.P) with the vehicle (deionized water) and different doses of Green-AgNPs (50, 100, 200, and 400 ppm), daily for 21 days. For the safety assessment, body weight and organ coefficient (liver, kidney, spleen, and brain) were measured. The effects of Green-AgNPs administration on working memory, anxiety behavior, novel object recognition, and spatial memory were analyzed. The lipophilic fluorescent products (LFPs), as an indicator of oxidative stress, were also evaluated in the liver, kidney, spleen, and hippocampus.

Results: After 21 days of exposure, significant changes were not observed in body weight and organ coefficients. Green-AgNPs at the doses of 100, 200, and 400 ppm caused memory impairment and anxieties as well as altered liver, kidney, spleen, and hippocampus redox status. All tissues of the exposed animals showed an increased LFPs level compared to those of the rats in the vehicle group.

Conclusions: This study indicated that the consumption of Green-AgNPs in higher doses (>50 ppm), not only had negative effects on behavioral indices but also caused memory impairment in rats and was toxic. This might be due to the induction of oxidative stress demonstrated by increased LFPs levels in tissues.

Graphical Abstract

Cascade events after I.P. injection of different doses of Green-AgNPs in rats

1. After I.P. administration of green synthesized AgNPs in rats, these particles can pass through endothelial cells to various organs, such as the liver, kidney, spleen, and brain.

2. Then caused oxidative stress and increased production of free radicals in the tissues.

3. Overload free radicals result in the initiation of lipid peroxidation and result in the production of aldehydes. Following changes in the redox state in the neurons, these events caused memory impairment in high doses of green synthesized AgNPs.

4. Aldehydes produced are unstable and react with amino groups of proteins, amino acids, or phospholipids.

5. Assessment of generated lipophilic fluorescent products (LFPs) as stress oxidative marker.

Keywords:

• Green synthesized silver nanoparticles
• hippocampus
• lipophilic fluorescent products
• Morris water maze
• oxidative stress

Acknowledgments

Hereby, we extend our gratitude to the Urmia University, Iran, for the financial support of this study.