Differences in cytotoxic, genotoxic, and inflammatory response of bronchial and alveolar human lung epithelial cells to pristine and COOH-functionalized multiwalled carbon nanotubes.

Cinzia Lucia Ursini,Delia Cavallo,Stefano Bellucci,Anna Maria Fresegna,Raffaele Maiello,Stefano Casciardi,Giuliana Buresti,Sergio Iavicoli,Aureliano Ciervo

doi:10.1155/2014/359506

Abstract

Functionalized MWCNTs are used in many commercial and biomedical applications, but their potential health effects are not well defined. We investigated and compared cytotoxic, genotoxic/oxidative, and inflammatory effects of pristine and carboxyl MWCNTs exposing human respiratory (A549 and BEAS-2B) cells to 1–40 μg/mL of CNTs for 24 h. Both MWCNTs induced low viability reduction (by WST1 assay) in A549 cells and only MWCNTs-COOH caused high viability reduction in BEAS-2B cells reaching 28.5% viability at 40 μg/mL. Both CNTs induced membrane damage (by LDH assay) with higher effects in BEAS-2B cells at the highest concentrations reaching 20% cytotoxicity at 40 μg/mL. DNA damage (by Fpg-comet assay) was induced by pristine MWCNTs in A549 cells and by both MWCNTs in BEAS-2B cells reaching for MWCNTs-COOH a tail moment of 22.2 at 40 μg/mL versus 10.2 of unexposed cells. Increases of IL-6 and IL-8 release (by ELISA) were detected in A549 cells exposed to MWCNTs-COOH from 10 μg/mL while IL-8 increased in BEAS-2B cells exposed to pristine MWCNTs at 20 and 40 μg/mL. The results show higher cytogenotoxicity of MWCNTs-COOH in bronchial and of pristine MWCNTs in alveolar cells. Different inflammatory response was also found. The findings suggest the use of in vitro models with different end points and cells to study CNT toxicity.

Highlights

Carbon nanotubes (CNTs), characterized by cylindrical shape and composed of carbon atoms, possess specific properties that make them useful for various consumer, medical, and industrial applications [1]
Increases of interleukine 6 (IL-6) and IL-8 release were detected in A549 cells exposed to MWCNTs-COOH from 10 μg/mL while IL-8 increased in BEAS-2B cells exposed to pristine MWCNTs at 20 and 40 μg/mL
As suggested in the study of Zhang et al [29], the slow uptake found in our study within the first 4 h could be explained by the fact that the MWCNTs take 2 h to deposit on the cell monolayer and the cells started to associate with MWCNTs for up to 16 h, at which time we found saturation of cell uptake for MWCNTs-COOH differently from pristine ones that continue to enter into the cells until 24 h exposure

Summary

Introduction

Carbon nanotubes (CNTs), characterized by cylindrical shape and composed of carbon atoms, possess specific properties that make them useful for various consumer, medical, and industrial applications [1] Given their increasing applications in composite materials and in new areas, which will lead to higher human exposure, it is very important to elucidate their potential adverse health effects. We evaluate and compare the toxicity of industrially produced pristine and -COOH functionalized MWCNTs, studying cytotoxic, genotoxic/oxidative effects and proinflammatory response on two human respiratory cell lines: lung alveolar epithelial cells (A549) and bronchial epithelial cells (BEAS-2B). Our study could be useful to clarify, in two different respiratory cell lines, the potential health effects of commercial CNTs, at low concentrations, and understand if chemical functionalization of MWCNTs, made to improve the dispersion, increases their toxicity before extending their applications in the biomedical field

Materials and Methods

Results

Discussion

Conclusions