Administration of Silver Nasal Spray Leads to Nanoparticle Accumulation in Rat Brain Tissues

Abstract

The use of commercial products containing engineered nanomaterials in realistic scenarios may lead to the accumulation of exogenous particles in brain tissues. In this study, we simulated the use of silver (Ag) nasal spray in humans using Sprague–Dawley rats at 0.04 mg/kg/day. Silver-containing particles were explicitly identified in the rat brain after the administration of nasal sprays containing colloidal Ag or silver ions (Ag+) for 2 weeks using multiple methods. The accumulation of Ag-containing particles showed a delayed effect in different brain regions of the rats, with the mass concentration of particles increasing continuously for 1–2 weeks after the termination of administration. The size of the observed Ag-containing particles extracted from the brain tissues ranged from 18.3 to 120.4 nm. Further characterization by high-resolution transmission electron microscopy with energy-dispersive spectroscopy showed that the nanoparticles comprised both Ag and sulfur (S), with Ag/S atomic ratios of 1.1–7.1, suggesting that Ag-containing particles went through a series of transformations prior to or during their accumulation in the brain. Collectively, these findings provide evidence for the accumulation and transformation of Ag-containing particles in the rat brain, indicating a realistic risk to brain health resulting from the application of Ag-containing commercial products.

Nanoscale Zinc-Based Metal–Organic Frameworks Induce Neurotoxicity by Disturbing the Metabolism of Catecholamine Neurotransmitters

“…The mice received 5 and 20 mg/kg/day nanoscale MOF-74-Zn via intranasal instillation for 14 days. Intranasal infusion is a commonly used route of administration to assess the neurotoxicity of nanoparticles. , These intranasal nanoparticles might be able to translocate into the olfactory bulb via olfactory neurons and accumulate in the brain . The level of zinc in the mouse brain increased significantly after exposure to 5 and 20 mg/kg/day MOF-74-Zn (Figure S2c), demonstrating that MOF-74-Zn nanoparticles were doubtlessly adsorbed into the CNS of the mice.…”

An Exosome-Based Therapeutic Strategy Targeting Neuroinflammation in Alzheimer’s Disease with Berberine and Palmatine

“…Besides, to further verify the therapeutic effects of Ber, Pal and the combined therapy (Ber/Pal) on neuroinflammation in AD, LPS (250 ng/mL) and Aβ 25-35 (20 μM) were utilized to stimulate microglia for NO and inflammatory cytokine detection (Figure 1A-E). The results showed that Ber and Pal significantly reduced the release of NO and reversed the abnormal inflammatory cytokine levels in microglia stimulated by LPS and Aβ [25][26][27][28][29][30][31][32][33][34][35] . Additionally, to evaluate the feasibility and therapeutic role of codelivery systems of Ber and Pal combined treatment in AD, a Ber and Pal combined treatment group was also included.…”

“…A LIPID MAPS internal standard cocktail was purchased from Avanti Polar Lipids (Alabaster, USA). Aβ peptide (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) (Aβ 25-35 ) was obtained from Beijing Bosen Biotechnology Co., Ltd. (Beijing, China). The PKH26 fluorescent probe was purchased from Maokangbio (Shanghai, China).…”

“…28 Studies have shown that nasal sprays, mixed micelles, and nanocarriers can improve bioavailability and crossing of the BBB in neurodegenerative diseases. [29][30][31] As a natural delivery carrier, Exos have stronger biocompatibility than other nanocarriers to prevent clearance by the immune system, and their natural targeting ability enhances their permeability to the brain due to their biogenic origin. 32,33 NIH-registered clinical experiments related to Exos include the neuroprotection of Exos in infants, diagnosis of diseases such as cerebral haemorrhage and stroke, and treatment of neurodegenerative diseases such as depression, anxiety, and dementia.…”

Genotoxic Effects on Daphnia magna Fed with Aquatic Green Algae Exposed to Silver Nanoclusters

“…Although numerous studies have been conducted to explore the potential ecotoxicology of large AgNPs in a variety of microorganisms [12,13], algae [14], plants [15], invertebrates [16,17] and vertebrates [18,19], these studies have largely concentrated on the effect on individual organisms, and only a few have described the toxicology of ultra-small AgNCs. The trophic toxicology of AgNCs to the aquatic food chain is a significant issue that warrants further research because several previous studies have shown that nanoparticles, including AgNPs, could potentially accumulate in aquatic ecosystems and eventually cause harm to the "top-level" species [20][21][22].…”