Assessment of iron oxide nanoparticle ecotoxicity on regeneration and homeostasis in the replacement model system Schmidtea mediterranea_suppl

Thao Tran

doi:10.14573/altex.1902061s

Abstract

Iron oxide nanoparticles (IONs) are used in a number of applications from food to cosmetics and from medical applications to magnetic storage. In spite of the 550 tons produced each year in Europe alone, no effective dose limit recommendations are established and the overall risks connected to IONs are still debated. The incorporation of IONs in daily life raises a concern about their effects on the environment, on living organisms, and on human health. In this study, we used freshwater planarians to assess the nanoecotoxicity of IONs. Planarians are free-living invertebrates known for their astonishing regenerative ability. Because of their sensitivity to toxicants, they are often used to determine the effects of toxic, genotoxic, and carcinogenic environmental compounds with an approach in line with the 3Rs (Reduce, Refine, Replace) principle. Planarians were exposed to IONs at concentrations up to 1 mg/ml and their effects were evaluated at the behavioral, morphofunctional, and molecular levels, with a special emphasis on the regeneration process. Our results indicate that IONs did not affect the stem cell population dynamics, nor did they induce substantial changes in either homeostatic or regenerating planarians. As positive controls, gold nanoparticles coated with the pro-apoptotic anti-cancer drug hexadecylmethylammonium bromide and highly concentrated polystyrene nanoparticles were used; these all elicited toxic effects. Therefore, we conclude that IONs at environmental concentrations are safe for planarians, and that the planarian is a powerful model system that can replace vertebrate animal models in nanoecotoxicology research and for nanoecotoxicology studies.

Highlights

Iron oxide nanoparticles (IONs) are used in numerous applications such as medical contrast agents, cosmetics, food additives, varnishes, coatings, pigmented thermoplastics, biosensors, and for cryobiotechnological applications (Gupta and Gupta, 2005; Kornberg et al, 2017; Lee et al, 2008; Minard and Wind, 2002; Peng et al, 2008; Semelka and Helmberger, 2001)
In order to assess whether ION accumulation could affect homeostasis at both cellular and molecular levels, we further investigated the effects of diet-borne IONs with regard to the production of reactive oxygen species, the ratio of the cell sub-populations, and gene expression
3.2.3 Planarian cell sub-populations To further investigate possible ION-induced effects at the cellular level, we focused on the planarian adult stem cell population, which is responsible for maintaining homeostasis by guaranteeing cellular turnover (Gentile et al, 2011; Rink, 2013)

Summary

Introduction

Iron oxide nanoparticles (IONs) are used in numerous applications such as medical contrast agents, cosmetics, food additives, varnishes, coatings, pigmented thermoplastics, biosensors, and for cryobiotechnological applications (Gupta and Gupta, 2005; Kornberg et al, 2017; Lee et al, 2008; Minard and Wind, 2002; Peng et al, 2008; Semelka and Helmberger, 2001). 2.6 Morphological analysis and assessment of the regeneration ability Homeostatic animals were assessed with regard to the animals’ survival rate, the viability of the different cell populations, the production of ROS, and the gene expression of ION-treated intact animals after 14 days exposure. 3.2 Effects of IONs on planarian homeostasis Effects induced by IONs on planarian homeostasis were evaluated 14 days after their first exposure to IONs. This part of the study included analysis of the survival rate, the behavioral changes, the ROS production, the viability and relative composition of the different cell populations, and gene expression.

Results

Conclusion