Adverse Effects of Industrial Multiwalled Carbon Nanotubes on Human Pulmonary Cells

Abstract

The aim of this study was to evaluate adverse effects of multiwalled carbon nanotubes (MWCNT), produced for industrial purposes, on the human epithelial cell line A549. MWCNT were dispersed in dipalmitoyl lecithin (DPL), a component of pulmonary surfactant, and the effects of dispersion in DPL were compared to those in two other media: ethanol (EtOH) and phosphate-buffered saline (PBS). Effects of MWCNT were also compared to those of two asbestos fibers (chrysotile and crocidolite) and carbon black (CB) nanoparticles, not only in A549 cells but also in mesothelial cells (MeT5A human cell line), used as an asbestos-sensitive cell type. MWCNT formed agglomerates on top of both cell lines (surface area 15–35 μm²) that were significantly larger and more numerous in PBS than in EtOH and DPL. Whatever the dispersion media, incubation with 100 μg/ml MWCNT induced a similar decrease in metabolic activity without changing cell membrane permeability or apoptosis. Neither MWCNT cellular internalization nor oxidative stress was observed. In contrast, asbestos fibers penetrated into the cells, decreased metabolic activity but not cell membrane permeability, and increased apoptosis, without decreasing cell number. CB was internalized without any adverse effects. In conclusion, this study demonstrates that MWCNT produced for industrial purposes exert adverse effects without being internalized by human epithelial and mesothelial pulmonary cell lines.

Acknowledgments

Lyes Tabet is a recipient of a joint grant from ADEME (Agence de l'Environnement et de la Maitrîse de l'Énergie) and ARKEMA. Part of this work was supported by the French ANR through RESPINTTOX project (SEST program) and by the Région Ile-de-France in the frame-work of C'nano-IdF, NANOTUBTOX project. C'Nano-IdF is the nanoscience competence center of Paris Region, supported by CNRS, CEA, MESR, and Région Ile-de-France. Nadia Amara is supported by Chancellerie des Universités de Paris (legs Poix) and Jorge Boczkowski by INSERM and Assistance Publique-Hôpitaux de Paris (Contrat d'Interface). The authors thank Marie-Annick Billon-Galland for her help and expertise in electronic microscopy, Marie-Claude Jaurand for providing the Met5A cells, and Hélène Desquerroux (ADEME) for her helpful comments. Ari Setyan and Michel J. Rossi acknowledge partial support from the French NANOTOX (ANR) program.