Asbestos and multi-walled carbon nanotubes generate distinct oxidative responses in inflammatory cells

Abstract

Asbestos exposure is considered a social burden by causing mesothelioma. Despite the use of synthetic materials, multi-walled carbon nanotubes (MWCNTs) are similar in dimension to asbestos and produce mesothelioma in animals. The role of inflammatory cells in mesothelial carcinogenesis remains unclear. Here, we evaluated the differences in inflammatory cell responses following exposure to these fibrous materials using a luminometer and L-012 (8-amino-5-chloro-7-phenylpyrido[3,4-d]pyridazine-1,4-(2H,3H) dione) to detect reactive oxygen species (ROS). Rat peripheral blood or RAW264.7 cells were used to assess the effects on neutrophils and macrophages, respectively. Crocidolite and amosite induced significant ROS generation by neutrophils with a peak at 10 min, whereas that of chrysotile was ~25% of the crocidolite/amosite response. MWCNTs with different diameters (~15, 50, 115 and 145 nm) and different carcinogenicity did not induce significant ROS in peripheral blood. However, the MWCNTs induced a comparable amount of ROS in RAW264.7 cells to that following asbestos treatment. The peaks for MWCNTs (0.5–1.5 h) were observed earlier than those for asbestos (1–5 h). Apocynin and superoxide dismutase significantly inhibited ROS generation for each fiber, suggesting an involvement of NADPH oxidase and superoxide. Thus, asbestos and MWCNTs induce different oxidative responses in inflammatory cells, indicating the importance of mesothelial cell evaluation for carcinogenesis.

Genotoxicity of nanomaterials in vitro: treasure or trash?

“…In particular, cellular DNA damage can result from direct interaction between CNTs and the genome, or indirectly via CNT-induced oxidative stress and inflammatory responses. Interestingly, at least for multi-walled CNTs, most of the ROS formation seems to result from cellular activation and an involvement of NADPH oxidase and superoxide radicals (Funahashi et al 2015). This is contrasting the results obtained with asbestos fibers, as do data that provide evidence that CNT fibers may also scavenging ROS to certain extents, an effect that actually should be inversely related to its genotoxicity (van Berlo et al 2012).…”

The Potential Protective Effects of Polyphenols in Asbestos-Mediated Inflammation and Carcinogenesis of Mesothelium

“…Hansen et al reported that the geometry and/or chemical composition of asbestos is important for the release of superoxide anions by leucocytes during frustrated phagocytosis [ 56 , 57 ]. Indeed, crocidolite and amosite induced significant ROS generation by neutrophils with a peak at 10 min, whereas that of chrysotile was ~25% of the crocidolite/amosite response [ 58 ].…”

The origin and future of oxidative stress pathology: From the recognition of carcinogenesis as an iron addiction with ferroptosis‐resistance to non‐thermal plasma therapy

“…Excess iron in the target cells was in common, which appears to have induced a common genetic alteration, homozygous deletion of p15 / p16 tumor suppressor genes. Early inflammatory responses by neutrophils were lacking for MWCNT …”