Histopathology and analyses of inflammation intensity in the gills of mussels exposed to silver nanoparticles: role of nanoparticle size, exposure time, and uptake pathways

Abstract

Environmentally induced perturbation of health parameters lead to morphological changes associated to the inflammatory response. Hematoxyline and eosin (H&E)-stained gill filaments sections were examined for such changes and inflammation intensity was scored according to a quantitative model in order to evaluate the health status of in vivo exposed (for 3, 6, and 12 h) mussels to silver nanoparticles (Ag-NPs <50 nm and Ag-NPs <100 nm) prior and after the inhibition of two potential uptake pathways (clathrin- and caveolae-mediated endocytosis) with the aid of pharmaceutical inhibitors (amantadine and nystatin). The impacts of the nanoparticles (NPs) size, as well as their uptake routes within different time of exposure on the inflammatory response were assessed. The results showed that Ag-NPs clearly induced morphological changes associated to the inflammatory response in gill tissues (Mann–Whitney p values were <.05). It is also clear that the length of the exposure as well as the NP size highly impacted inflammation intensity (highest histopathological indices recorded with Ag-NPs <100 nm). Also, the routes of NPs entry noticed to be major factor underlying inflammatory response (significant inflammation intensity reported with Ag-NPs <50 nm after blockade of uptake routes; p <.05). Throughout, it was concluded that inflammation intensity was related to NPs size and exposure time. Overall, uptake routes are shown to be the major factor underlying nanotoxicity.

Keywords:

• Innate immunity
• inflammation
• nanotoxicity
• Mytilus galloprovincialis
• immunotoxicity

Acknowledgements

Authors acknowledge the staff of Pathological anatomy department of the Regional Hospital of Menzel Bourguiba, Bizerte, Tunisia. The authors also thank Prof. Michael N. Moore (BSc (Hons), PhD, FRMS) Professor at The European Centre for Environment & Human Health (ECEHH), University of Exeter Medical School, Truro; Professor at School of Biological Sciences, University of Plymouth; PML Fellow at Plymouth Marine Laboratory, Plymouth, (United Kingdom), for reviewing this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study is funded by the Immuno-microbiology, Environmental and Cancerogesis IMEC Research Unit (Sciences Faculty of Bizerte, University of Carthage).