PLoS ONE (Jan 2018)

Long-term polarization of alveolar macrophages to a profibrotic phenotype after inhalation exposure to multi-wall carbon nanotubes.

  • Kunihiro Otsuka,
  • Koichi Yamada,
  • Yuhji Taquahashi,
  • Rieko Arakaki,
  • Aya Ushio,
  • Masako Saito,
  • Akiko Yamada,
  • Takaaki Tsunematsu,
  • Yasusei Kudo,
  • Jun Kanno,
  • Naozumi Ishimaru

DOI
https://doi.org/10.1371/journal.pone.0205702
Journal volume & issue
Vol. 13, no. 10
p. e0205702

Abstract

Read online

BACKGROUND:Nanomaterials are widely used in various fields. Although the toxicity of carbon nanotubes (CNTs) in pulmonary tissues has been demonstrated, the toxicological effect of CNTs on the immune system in the lung remains unclear. METHODS AND FINDING:In this study, exposure to Taquann-treated multi-walled CNTs (T-CNTs) was performed using aerosols generated in an inhalation chamber. At 12 months after T-CNT exposure, alveolar inflammation with macrophage accumulation and hypertrophy of the alveolar walls were observed. In addition, fibrotic lesions were enhanced by T-CNT exposure. The macrophages in the bronchoalveolar lavage fluid of T-CNT-exposed mice were not largely shifted to any particular population, and were a mixed phenotype with M1 and M2 polarization. Moreover, the alveolar macrophages of T-CNT-exposed mice produced matrix metalloprotinase-12. CONCLUSIONS:These results suggest that T-CNT exposure promoted chronic inflammation and fibrotic lesion formation in profibrotic macrophages for prolonged periods.