Transcriptional profile of mouse lung during the fibrotic phase of the response to bleomycin

Wildtype mice were given saline or bleomycin by oropharyngeal instillation. After 14 days, during the fibrotic phase of the response, lungs were dissected and total RNA was extracted and used for gene expression profiling. The aim was to identify those genes regulated during the development of fibrosis in this animal model of bleomycin-induced lung fibrosis. Wildtype male C57Bl/6J mice (8-10 weeks old) were used in the study, with three mice per group. Bleomycin (1mg/kg body weight in 50μl of saline) or saline was administered by oropharyngeal installation as described previously by Lakatos et al, Exp Cell Res, 2006, under light halothane-induced anaesthesia. After 14 days, lungs were removed, blotted dry and the trachea and major airways were excised before the separated lobes were snap frozen in liquid nitrogen. Lungs were then pulverized under liquid nitrogen, and the resulting lung powder was used for total RNA extraction using Trizol. Following DNase-treatment, clean-up, cDNA synthesis and cRNA synthesis, samples were hybridized to Affymetrix MOE430A genechips using standard protocols. The data were analyzed using RMA with quantiles normalization.