title: Analysis of pulmonary surfactant in rat lungs after intratracheal instillation of short and long multi-walled carbon nanotubes.
abstract: Multi-walled carbon nanotubes (MWCNTs) are interesting new materials, but there is some concern about their harmfulness due to their fibrous nature. To determine the difference in the biological effects of MWCMTs by fiber length, we prepared two MWCNT samples from one bulk sample. One consisted of cut up short fibers (Short; average length=0.94 µm) and the other was just dispersed (Long; average length=3.4 µm). The samples were administered to male Wistar rats by intratracheal instillation at doses of 0.2 mg and 1 mg/animal (Short) and 0.2 mg and 0.6 mg/animal (Long). The animals were sacrificed at time points from 3 d to 12 months after administration. Bronchoalveolar lavage fluid (BALF) was taken from the lungs and pathological specimens were prepared. The concentrations of phospholipids, total protein and surfactant protein D (SP-D) in the pulmonary surfactant of the BALF were determined, the surface tension of BALF was measured, and the inflammation score was determined by the point-counting method to assess pulmonary tissue inflammation. The present study suggests that inflammatory response in the lung was slightly higher for long MWCNTs than for short MWCNTs when compared at the same mass dose. The correlation between pulmonary surfactant components and BALF surface tension was also evaluated. The Spearman's rank correlation coefficients obtained for the phospholipid, total protein and SP-D concentrations were -0.068 (p=0.605), -0.360 (p=0.005) and -0.673 (p=0.000), respectively. Surface tension, measured by a simple method, should be reflected in the change of a surfactant protein, such as SP-D.
authors.affiliation: Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health , Kitakyushu , Japan and.
authors.forename: Byeong-Woo
authors.initials: BW
authors.lastname: Lee
authors.forename: Chikara
authors.initials: C
authors.lastname: Kadoya
authors.forename: Masanori
authors.initials: M
authors.lastname: Horie
authors.forename: Yohei
authors.initials: Y
authors.lastname: Mizuguchi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Hashiba
authors.forename: Tatsunori
authors.initials: T
authors.lastname: Kambara
authors.forename: Takami
authors.initials: T
authors.lastname: Okada
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Myojo
authors.forename: Takako
authors.initials: T
authors.lastname: Oyabu
authors.forename: Akira
authors.initials: A
authors.lastname: Ogami
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Isamu
authors.initials: I
authors.lastname: Tanaka
authors.forename: Kunio
authors.initials: K
authors.lastname: Uchida
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Endoh
authors.forename: Junko
authors.initials: J
authors.lastname: Nakanishi
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry* / Q000166:cytology; D007958:Leukocyte Count; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D037742:Nanotubes, Carbon / Q000633:toxicity*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects; D010743:Phospholipids / Q000378:metabolism; D011014:Pneumonia / Q000378:metabolism / Q000473:pathology; D037663:Pulmonary Surfactant-Associated Protein D / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D037742:Nanotubes, Carbon; D010743:Phospholipids; D037663:Pulmonary Surfactant-Associated Protein D