Differential effects of long and short carbon nanotubes on the gas-exchange region of the mouse lung

Abstract

We hypothesise that inflammatory response and morphological characteristics of lung parenchyma differ after exposure to short or long multi-walled carbon nanotubes (MWCNT). Mice were subjected to a single dose of vehicle, short or long MWCNT by pharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) obtained at 24 h was analysed for inflammatory reaction and lung tissue was analysed for morphological alterations using stereology. Short MWCNT had stronger potential to induce polymorphonuclear cells whereas long MWCNT increased interleukin-6 levels in BALF. Alveolar septal fibrosis was only observed with short MWCNT. Type II pneumocyte hypertrophy was only detected with long MWCNT. There was no reduction in total alveolar surface area and no sign of type II cell hyperplasia. We observed mild inflammatory and pathological responses to short and long MWCNT in the lung parenchyma depending on the size of the applied MWCNT.

Keywords::

• Carbon nanotubes
• stereology
• transmission electron microscopy

Acknowledgments

The authors wish to thank Andrea Stokes (Bern) and Tamara Papadakis (Gießen) for technical assistance with the preparation of the microscopic samples. CM, PG and BRR would like to thank the Swiss National Foundation for financial support (grant No. 3100A0_118420). CAP, RD and KD also wish to thank the Colt Foundation for financial support, and FAM would like to thank the Department of Health for financial support. We would also like to thank Mr Steve Clark (IOM), Mr Gordon Fern (IOM) and Mr Steve Mitchell (UoE) for assistance with SEM and TEM characterisation of the CNT morphology.