each mouse received 18, 54, or 162 µg of TiO2NPs or only the vehicle via single intratracheal instillation. Mice were anaesthetised and intratracheally instilled with particle suspensions as described previously (Saber et al 2012, Particle and Fiber Toxicology). Whole lung tissues were collected 24 h and 28 d post exposure, flash frozen in liquid nitrogen and stored at -80°C until the analysis.
Extracted molecule
total RNA
Extraction protocol
In brief, a small frozen section of lung tissue was homogenized in Trizol (Invitrogen, Carlsbad, CA, USA) using the Retsch Mixer MM 400. RNA was isolated using chloroform, precipitated using isopropyl alcohol and purified using RNeasy Mini Kits (Qiagen, Mississauga, ON, Canada). All RNA showed high integrity with a A260/280 ratio between 2.0 and 2.2 and RNA integrity number above 7.0.
Label
Cy5
Label protocol
Agilent Linear Amplification Kit (Agilent Technologies Inc., Mississauga, ON, Canada) was used to synthesize cDNA and labelled cRNA from 200 ng of total RNA derived from each individual mouse lungs and commercially available Universal Mouse Reference RNA (UMRR, Stratagene, Mississauga, ON, Canada). Cyanine-labelled cRNA was in vitro transcribed using T7 RNA polymerase and purified using RNeasy Mini Kits (Qiagen, Mississauga, ON, Canada). Experimental samples were labelled with Cyanine-5 and the UMRR was labelled with Cyanine-3.
Channel 2
Source name
Universal Mouse Reference RNA (UMRR, Stratagene, Mississauga, ON, Canada)
each mouse received 18, 54, or 162 µg of TiO2NPs or only the vehicle via single intratracheal instillation. Mice were anaesthetised and intratracheally instilled with particle suspensions as described previously (Saber et al 2012, Particle and Fiber Toxicology). Whole lung tissues were collected 24 h and 28 d post exposure, flash frozen in liquid nitrogen and stored at -80°C until the analysis.
Extracted molecule
total RNA
Extraction protocol
In brief, a small frozen section of lung tissue was homogenized in Trizol (Invitrogen, Carlsbad, CA, USA) using the Retsch Mixer MM 400. RNA was isolated using chloroform, precipitated using isopropyl alcohol and purified using RNeasy Mini Kits (Qiagen, Mississauga, ON, Canada). All RNA showed high integrity with a A260/280 ratio between 2.0 and 2.2 and RNA integrity number above 7.0.
Label
Cy3
Label protocol
Agilent Linear Amplification Kit (Agilent Technologies Inc., Mississauga, ON, Canada) was used to synthesize cDNA and labelled cRNA from 200 ng of total RNA derived from each individual mouse lungs and commercially available Universal Mouse Reference RNA (UMRR, Stratagene, Mississauga, ON, Canada). Cyanine-labelled cRNA was in vitro transcribed using T7 RNA polymerase and purified using RNeasy Mini Kits (Qiagen, Mississauga, ON, Canada). Experimental samples were labelled with Cyanine-5 and the UMRR was labelled with Cyanine-3.
Hybridization protocol
Equal amount (300 ng) of labelled cRNA from each experimental sample was hybridized to Agilent Sureprint G3 Mouse GE 4x44K microarrays (agilent Technologies Inc., Mississuaga, ON, Canada) at 65°C for 17 hours in the Agilent SureHyb Hybridization chamber.
Scan protocol
Scanned on an Agilent G2565AA scanner.
Data processing
Images were quantified using Agilent Feature Extraction Software (version A.8.5.1.1). Non background subtracted median signal intensities were LOWESS normalized using the maanova library in R. Probes with technical replicates were averaged using the median.
