Transcriptomic analysis of mouse lung tissue exposed to two multiwalled carbon nanotubes (NRCWE-26 and NM-401)

Multi-walled carbon nanotubes (MWCNTs) are extensively produced and used in composite materials and electronic applications, thus increasing risk of worker and consumer exposure. MWCNTs are an inhomogeneous group of nanomaterials that exist in various lengths, shapes and with different metal compositions, which makes hazard evaluation difficult. However, several studies suggest that length plays an important role in the toxicity induced by MWCNTs. How the length influences toxicity at the molecular level is yet to be characterized. We used high-content genomics tools to compare pulmonary responses after exposure to a short, entangled MWCNT to the pulmonary responses after exposure to a long, stiffer MWCNT at the global transcriptomic level. Female C57BL/6 mice were exposed by single intratracheal instillation to 18, 54 or 162 µg/mouse of a short MWCNT (NRCWE-26 (NC-7000), 847±102 nm in length) or long MWCNT (NM-401 (CP-0006-SG), 4048±366 nm in length). Lung tissues were harvested 24 h, 3 d and 28 d after exposure. This experiment examined the pulmonary transcriptional response of female C57BL/6 mice exposed to NRCWE-26, a short multi-walled carbon nanotube, and NM-401, a long multi-walled carbon nanotube, at three doses: D1 (18 μg), D2 (54 μg), D3 (162 μg), and vehicle control. Each dose group was examined 1, 3 or 28 days post-exposure. Each dose group had 5-6 biological replicates. There were a total of 139 samples included in the final analysis using a two-color reference design.