In Vitro Analysis of the Effects of ITER-Like Tungsten Nanoparticles: Cytotoxicity and Epigenotoxicity in BEAS-2B Cells

Abstract

Tungsten was chosen as a wall component to interact with the plasma generated by the International Thermonuclear Experimental fusion Reactor (ITER). Nevertheless, during plasma operation tritiated tungsten nanoparticles (W-NPs) will be formed and potentially released into the environment following a Loss-Of-Vacuum-Accident, causing occupational or accidental exposure. We therefore investigated, in the bronchial human-derived BEAS-2B cell line, the cytotoxic and epigenotoxic effects of two types of ITER-like W-NPs (plasma sputtering or laser ablation), in their pristine, hydrogenated, and tritiated forms. Long exposures (24 h) induced significant cytotoxicity, especially for the hydrogenated ones. Plasma W-NPs impaired cytostasis more severely than the laser ones and both types and forms of W-NPs induced significant micronuclei formation, as shown by cytokinesis-block micronucleus assay. Single DNA strand breaks, potentially triggered by oxidative stress, occurred upon exposure to W-NPs and independently of their form, as observed by alkaline comet assay. After 24 h it was shown that more than 50% of W was dissolved via oxidative dissolution. Overall, our results indicate that W-NPs can affect the in vitro viability of BEAS-2B cells and induce epigenotoxic alterations. We could not observe significant differences between plasma and laser W-NPs so their toxicity might not be triggered by the synthesis method.

From Basic Research to New Tools and Challenges for the Genotoxicity Testing of Nanomaterials

“…As already reported in the literature, oxidative stress was suggested as one mechanism involved in the genotoxic responses observed [ 2 , 3 , 4 , 9 ]. Co-exposure to nanomaterials and other compounds can affect the genotoxicity [ 2 , 6 ].…”

“…This issue contains mostly data from in vitro studies. In addition to classical cell lines such as hamster and human fibroblasts [ 1 , 2 ] or human lung cells [ 3 , 4 ], new models have been also used for investigating nanomaterials genotoxicity: ToxTracker reporter cell lines [ 5 ], human amniotic cells [ 6 ] and 3D HepG2 spheroids [ 7 ]. In this issue, three papers also deal with in vivo studies: on the plant Allium cepa [ 8 ], on the tadpoles of Xenopus laevis [ 9 ] and on rats [ 10 ].…”

“…Among the various assays available for investigating genotoxicity and mutagenicity, most of the papers used the comet assay to visualize the DNA fragmentation both in in vitro [ 3 , 4 , 6 , 7 ] and in vivo [ 10 ] studies. The micronucleus assay to detect chromosome and genome mutations was also largely performed in cell lines [ 2 , 4 ] as well as in whole organisms [ 8 , 9 , 10 ]. In contrast, only one article deals with the gene mutation Hprt assay [ 1 ].…”

“…Similarly, the thermal reduction of graphene oxides generates a material that was no longer genotoxic at low concentrations [ 9 ]. In contrast, the type of synthesis used for producing tungstene particles did not significantly affect the toxicity [ 4 ]. The impact of size was investigated on the toxic responses either using two protocols of dispersion with TiO 2 nanoparticles leading to different size distribution [ 1 ] or by testing similar nanomaterials with different primary sizes [ 5 ].…”

Predicting Cytotoxicity of Metal Oxide Nanoparticles Using Isalos Analytics Platform

“…In vitro toxicological analyses were carried out both in single- and multiparameter toxicity assays. Single-parameter ATP and LDH assays in human bronchial epithelial (BEAS-2B) and murine myeloid (RAW 264.7) cell lines were included as they are commonly used to assess engineered NPs cytotoxicity without reference to a specific MOA [ 61 , 62 ]. Results from these single-parameter toxicity analyses were compared with results from an in-house multiparameter high-throughput screening assay containing 5 parameters measuring oxidative stress [ 45 ].…”