Histological and biochemical evaluation of the effects of silver nanoparticles (AgNps) versus titanium dioxide nanoparticles (TiO₂NPs) on rat parotid gland

ABSTRACT

The unlimited use of nanoparticles (NPs) results in toxic impacts on different tissues. The current study aimed to compare the adverse effects of AgNPs and TiO₂NPs on the parotid gland of adult male albino rats as regards the histopathological, immunohistochemical, and biochemical changes, exploring the possible underlying mechanisms and the degree of improvement after cessation of administration. Fifty-four adult male albino rats were divided into control group (I), AgNPs-injected group (II), and TiO₂NPs-injected group (III). We measured the levels of tumor necrosis factor-alpha (TNF-α) and interleukin (IL-6) in the serum, and levels of MDA and GSH in parotid tissue homogenate. Quantitative real-time polymerase-chain reaction (qRT-PCR) was used to measure the expression levels of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC1-α), nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4), mouse double minute 2 (MDM2), Caspase-3 Col1a1, and Occludin. Parotid tissue sections were examined by light microscope (Hematoxylin & Eosin and Mallory trichrome stains), electron microscope, and immunohistochemical examination of CD68 and anti-caspase-3 antibodies. Both NPs severely affected the acinar cells and damaged the tight junction between them by enhancing expression of the inflammatory cytokines, inducing oxidative stress, and disturbing the expression levels of the studied genes. They also stimulated fibrosis, acinar cell apoptosis, and inflammatory cells infiltration in parotid tissue. TiO₂NPs effects were less severe than AgNPs. Cessation of exposure to both NPs, ameliorated the biochemical and structural findings with more improvement in TiO₂NPs withdrawal. In conclusion: AgNPs and TiO₂NPs adversely affected the parotid gland, but TiO₂NPs were less toxic than AgNPs.

KEYWORDS:

• Biochemical, rats
• histological
• parotid gland
• Silver nanoparticles (AgNPs)
• Titanium dioxide nanoparticles (TiO₂NPs)

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No potential conflict of interest was reported by the author(s).

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All authors have read and approved the final version of the manuscript.

Authorship contribution statement

Abdel Aal S M, Mohammed M Z & Abdelrahman S A: Creating the idea of research, performing the practical part of histological, immunohistochemical, and electron microscope examination. Writing the methods of histology and performing the morphometry and statistics of histology results. Abdelrahman A A& Samy W: Performing the biochemical analysis and statistics and writing the biochemical methods and results. Deraz R H: Data collection and presentation, writing the discussion section. Abdelaal G M M: Shared in manuscript writing and responsible for references editing. All authors revised and approved the final manuscript for publication.

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Funding

This research was self-funded by the authors and did not receive any specific grant from any funding agency