title: Pulmonary biocompatibility assessment of inhaled single-wall and multiwall carbon nanotubes in BALB/c mice.
abstract: With the widespread application of carbon nanotubes (CNTs) in diverse commercial processes, scientists are now concerned about the potential health risk of occupational exposures. In this study, CNT-induced pulmonary toxicity was investigated by exposing BALB/c mice to aerosolized single-wall (SW) CNT and multiwall (MW) CNT (5 μg/g of mice) for 7 consecutive days in a nose-only exposure system. Microscopic studies showed that inhaled CNTs were homogeneously distributed in the mouse lung. The total number of bronchoalveolar lavage polymorphonuclear leukocytes recovered from the mice exposed to SWCNT and MWCNT (1.2 × 10(6) ± 0.52 and 9.87 × 10(5) ± 1.45; respectively) was significantly greater than control mice (5.46 × 10(5) ± 0.78). Rapid development of pulmonary fibrosis in mice that inhaled CNT was also confirmed by significant increases in the collagen level. The lactate dehydrogenase levels were increased nearly 2- and 2.4-fold in mice that inhaled SWCNT and MWCNT, respectively, as compared with control mice. In addition, exposure of CNTs to mice showed a significant (p < 0.05) reduction of antioxidants (glutathione, superoxide dismutase, and catalase) and induction of oxidants (myloperoxidase, oxidative stress, and lipid peroxidation) compared with control. Apoptosis-related proteins such as caspase-3 and -8 activities were also significantly increased in mice that inhaled CNT than in control mice. Together, this study shows that inhaled CNTs induce inflammation, fibrosis, alteration of oxidant and antioxidant levels, and induction of apoptosis-related proteins in the lung tissues to trigger cell death.
authors.affiliation: Center for Biotechnology and Biomedical Sciences, Department of Biology, Norfolk State University, Norfolk, Virginia 23504, USA.
authors.forename: Prabakaran
authors.initials: P
authors.lastname: Ravichandran
authors.forename: Sudhakar
authors.initials: S
authors.lastname: Baluchamy
authors.forename: Ramya
authors.initials: R
authors.lastname: Gopikrishnan
authors.forename: Santhoshkumar
authors.initials: S
authors.lastname: Biradar
authors.forename: Vani
authors.initials: V
authors.lastname: Ramesh
authors.forename: Virupaxi
authors.initials: V
authors.lastname: Goornavar
authors.forename: Renard
authors.initials: R
authors.lastname: Thomas
authors.forename: Bobby L
authors.initials: BL
authors.lastname: Wilson
authors.forename: Robert
authors.initials: R
authors.lastname: Jeffers
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Hall
authors.forename: Govindarajan T
authors.initials: GT
authors.lastname: Ramesh
mesh_terms: D000336:Aerosols; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D008422:Materials Testing; D051379:Mice; D008807:Mice, Inbred BALB C; D037742:Nanotubes, Carbon / Q000009:adverse effects*; D018384:Oxidative Stress / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism; D011014:Pneumonia / Q000139:chemically induced* / Q000378:metabolism* / Q000473:pathology; D011658:Pulmonary Fibrosis / Q000139:chemically induced* / Q000378:metabolism* / Q000473:pathology
chemical_list: D000336:Aerosols; D000975:Antioxidants; D037742:Nanotubes, Carbon; D010088:Oxidoreductases; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; D053148:Caspase 3; D053181:Caspase 8