Pulmonary and Systemic Immune Response to Inhaled Multiwalled Carbon Nanotubes

Abstract

Inhalation of multiwalled carbon nanotubes (MWCNTs) at particle concentrations ranging from 0.3 to 5 mg/m3 did not result in significant lung inflammation or tissue damage, but caused systemic immune function alterations. C57BL/6 adult (10- to 12-week) male mice were exposed by whole-body inhalation to control air or 0.3, 1, or 5 mg/m3 respirable aggregates of MWCNTs for 7 or 14 days (6 h/day). Histopathology of lungs from exposed animals showed alveolar macrophages containing black particles; however, there was no inflammation or tissue damage observed. Bronchial alveolar lavage fluid also demonstrated particle-laden macrophages; however, white blood cell counts were not increased compared to controls. MWCNT exposures to 0.3 mg/m3 and higher particle concentrations caused nonmonotonic systemic immunosuppression after 14 days but not after 7 days. Immunosuppression was characterized by reduced T-cell-dependent antibody response to sheep erythrocytes as well as T-cell proliferative ability in presence of mitogen, Concanavalin A. Assessment of nonspecific natural killer (NK) cell activity showed that animals exposed to 1 mg/m(3) had decreased NK cell function. Gene expression analysis of selected cytokines and an indicator of oxidative stress were assessed in lung tissue and spleen. No changes in gene expression were observed in lung; however, interleukin-10 (IL-10) and NAD(P)H oxidoreductase 1 mRNA levels were increased in spleen.

Aerosolization System for Experimental Inhalation Studies of Carbon-Based Nanomaterials

“…There are few studies that have developed aerosolization systems and delivered carbon-based nanomaterials via inhalation (Li et al 2007;Mitchell et al 2007;Ryman-Rasmussen et al 2008;Shvedova et al 2008). In the Mitchell et al (2007) study, MW-CNTs were aerosolized with a jet mill coupled to a dry chemical screw feeder and a 2-µm cut-point cyclone.…”

“…In the Mitchell et al (2007) study, MW-CNTs were aerosolized with a jet mill coupled to a dry chemical screw feeder and a 2-µm cut-point cyclone. For MWCNTs concentrations of 500-1000 µg/m 3 , these authors report an MMAD of approximately 0.7-1 µm (∼2.0 geometric SD) and a median particle number size distribution of approximately 350-400 nm.…”

“…For example, a system encompassing an acoustic fluidization feeder, mill, and size separator was used to generate aerosolized single-walled carbon nanotubes (SW-CNTs; Baron et al 2008), whereas a jet mill coupled to a dry chemical screw feeder (Mitchell et al 2007) or a 6-jet collision nebulizer (Ryman-Rasmussen et al 2008) was utilized to aerosolize multiwalled carbon nanotubes (MW-CNTs). Other test systems employed for generating nanomaterials have included a brush dust generator for inhalation studies of nanotitanium dioxide (Ma-Hock et al 2009), as well as a direct delivery of aerosolized nanomaterials from an evaporation reactor (e.g., silicon dioxide; Ostraat et al 2008) or combustion with a laminar diffusion flame system (e.g., ultrafine iron; Yang et al 2001).…”

“…Some of the challenges faced in aerosolizing both MW-CNTs and SW-CNTs include particle agglomeration and the relatively low efficiency in delivering an aerosol in the respirable size range to the animal exposure chamber , which results in relatively large quantities of bulk material being required to meet the target aerosol concentration (Mitchell et al 2007;Baron et al 2008). Because new nanomaterials may only be produced in small quantities during the research and development phase, researchers could utilize an approach for toxicity and hazard comparison studies to deliver relatively small quantities of different nanomaterials by inhalation with similar aerodynamic aerosol properties.…”

Gold nanoparticles and ions – friends or foes? As they are seen by human cells U-937 and HL-60

“…That was the case of the study of multi-walled carbon nanotubes acting in a mouse model, where no induction of inflammation was showed, while macrophage activation and development of the inflammatory response was observed for single-walled carbon nanotubes. [14,15] In the last decade, a lot of methods for the synthesis of AuN with the defined parameters, such as size or shape was developed.…”