title: Multi-walled carbon nanotubes induce cytotoxicity and genotoxicity in human lung epithelial cells.
abstract: The increasing use of nanomaterials in consumer products highlights the importance of understanding their potential toxic effects. We evaluated cytotoxic and genotoxic/oxidative effects induced by commercial multi-walled carbon nanotubes (MWCNTs) on human lung epithelial (A549) cells treated with 5, 10, 40 and 100 µg ml⁻¹ for different exposure times. Scanning electron microscopy (SEM) analysis, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and lactate dehydrogenase (LDH) assays were performed to evaluate cytotoxicity. Fpg-modified comet assay was used to evaluate direct-oxidative DNA damage. LDH leakage was detected after 2, 4 and 24 h of exposure and viability reduction was revealed after 24 h. SEM analysis, performed after 4 and 24 h exposure, showed cell surface changes such as lower microvilli density, microvilli structure modifications and the presence of holes in plasma membrane. We found an induction of direct DNA damage after each exposure time and at all concentrations, statistically significant at 10 and 40 µg ml⁻¹ after 2 h, at 5, 10, 100 µg ml⁻¹ after 4 h and at 10 µg ml⁻¹ after 24 h exposure. However, oxidative DNA damage was not found. The results showed an induction of early cytotoxic effects such as loss of membrane integrity, surface morphological changes and MWCNT agglomerate entrance at all concentrations. We also demonstrated the ability of MWCNTs to induce early genotoxicity. This study emphasizes the suitability of our approach to evaluating simultaneously the early response of the cell membrane and DNA to different MWCNT concentrations and exposure times in cells of target organ. The findings contribute to elucidation of the mechanism by which MWCNTs cause toxic effects in an in vitro experimental model.
authors.affiliation: INAIL, National Institute for Occupational Safety and Prevention, Department of Occupational Medicine, Via Fontana Candida 1, 00040 Monteporzio Catone, Rome, Italy.
authors.forename: Delia
authors.initials: D
authors.lastname: Cavallo
authors.forename: Carla
authors.initials: C
authors.lastname: Fanizza
authors.forename: Cinzia Lucia
authors.initials: CL
authors.lastname: Ursini
authors.forename: Stefano
authors.initials: S
authors.lastname: Casciardi
authors.forename: Emilia
authors.initials: E
authors.lastname: Paba
authors.forename: Aureliano
authors.initials: A
authors.lastname: Ciervo
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Fresegna
authors.forename: Raffaele
authors.initials: R
authors.lastname: Maiello
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Marcelloni
authors.forename: Giuliana
authors.initials: G
authors.lastname: Buresti
authors.forename: Francesca
authors.initials: F
authors.lastname: Tombolini
authors.forename: Stefano
authors.initials: S
authors.lastname: Bellucci
authors.forename: Sergio
authors.initials: S
authors.lastname: Iavicoli
mesh_terms: D056809:Alveolar Epithelial Cells / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D004249:DNA Damage; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008871:Microvilli / Q000187:drug effects / Q000648:ultrastructure; D009153:Mutagens / Q000145:classification / Q000633:toxicity*; D037742:Nanotubes, Carbon / Q000145:classification / Q000633:toxicity* / Q000648:ultrastructure; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism
chemical_list: D009153:Mutagens; D037742:Nanotubes, Carbon; D013778:Tetrazolium Salts; D013844:Thiazoles; D007770:L-Lactate Dehydrogenase; C022616:thiazolyl blue