Gene expression profiles in rat lung following intratracheal instillation with single-wall carbon nanotubes

Gene expression profiling of the rat lung following intratracheal instillation with single-wall carbon nanotubes (SWCNTs) was employed to gain insights into these molecular events. We attempted to characterize time-dependent changes in the gene expression until 754 days after intratracheal instillation with SWCNTs suspensions at 0.2 mg (L-SWCNT) and 0.4 mg (H-SWCNT) injected dose per rat, and to identify the shift from the acute-phase to the chronic-phase phase on the basis of evaluation at the molecular level. Groups of nine-week-old male Wistar rats (n= 6 per group/ time point) were intratracheally instilled with single-wall carbon nanotubes (SWCNTs) suspended in 0.4 ml distilled water including 0.1% Triton X-100 as a single injection 0.1 mg (L-SWCNT) and 0.4 mg (H-SWCNT) SWCNTs/ rat). Control groups received 0.1% Triton X-100 (vehicle control). After intratracheal instillation treatment, rats were housed within polycarbonate cages at a controlled temperature of 22 °C with a chow diet ad libitum, and dissected at 3 days, 7 days, 30 days, 90 days, 180 days, 365 days and 754 days post-instillation. Right lungs of anesthetized rats were perfused with physiological saline, excised, and used for DNA microarray analysis.