Comparison of the effects of MnO₂-NPs and MnO₂-MPs on mitochondrial complexes in different organs

Abstract

Today, nanoparticles (NPs) have been widely used in various fields. Manganese oxide nanoparticles have attracted a lot of attention due to many applications. One of the major concerns regarding the widespread use of various NPs is the exposure and accumulation in human organs and finally toxicity. The generation of reactive oxygen species (ROS) by mitochondria is one of the most important mechanisms of toxicity suggested by published studies induced by other NPs. However, limited studies have been conducted on the mechanism of toxicity of MnO₂-NPs and MnO₂-microparticles (MnO₂-MPs). In this study, we compared the accumulation of MnO₂-NPs and MnO₂-MPs in different tissues and evaluated their effects on mitochondrial complexes in isolated mitochondria. Our results showed that intravascular (iv) administration of the MnO₂-NPs in the same dose compared to the MnO₂-MPs resulted in more accumulation in the C57 mouse female tissues. The effect of MnO₂-NPs and MnO₂-MPs in mitochondria showed that complexes I and III play an important role in increasing ROS generation and this effect is related to type of tissue. Also, our results showed that exposure to MnO₂-NPs and MnO₂-MPs reduced the activity of mitochondrial complexes II and IV. Our results suggest that the toxicity of the MnO₂-NPs is higher than that of the MnO₂-MPs and can lead to the depletion of antioxidant status, likely induction of apoptosis, cancer, and neurodegenerative disease.

Abbreviations: NPs: nanoparticles; ROS: reactive oxygen species; SDH: succinate dehydrogenase; DCFH-DA: dichloro-dihydro-fluorescein diacetate; ELISA: enzyme-linked immunosorbent assay; MnO2-NPs: manganese oxide nanoparticles

Keywords:

• MnO₂-NPs
• MnO₂-MPs
• ROS
• mitochondrial complexes
• toxicity
• mechanism

Acknowledgement

The data provided in this article was extracted from the PhD thesis of Dr Asghar Ashrafi Hafez. The thesis was conducted under supervision of Dr Ahmad Salimi at Department of Pharmacology and Toxicology, School of Pharmacy, Ardabil University of Medical Sciences and Dr Amir Mohammad Mortazavian at Department of Food Science and Technology, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by Shahid Beheshti University of Medical Sciences, Deputy of Research [grant number (9489)].