ObjectiveTo investigate the molecular pathogenesis of pulmonary fibrosis induced by bleomycin in a murine model,and provide novel insights for clinical diagnosis and treatment. MethodsFrom Gene Expression Omnibus,we downloaded microarray data extracted from experiments of bleomycin induced pulmonary fibrosis in wild-type mice. With BRB-Array Tools,differentially expressed genes at different time points during disease development were screened,selected and analyzed by DAVID software. ResultsBRB array analysis identified 45101 differentially expressed genes. After induction by bleomycin on 7th day,1164 genes and 735 genes were significantly up-regulated and down-regulated (P<0.05,fold change>2),respectively. On 14th day,731 genes and 390 genes were significantly up-regulated and down-regulated (P<0.05,fold change>2),respectively. DAVID analysis revealed that the up-regulated genes were significantly enriched in cell cycle,p53 signaling and chemokine signaling pathway,damaging reaction and collagen metabolism gene sets. While the down-regulated genes were enriched in the drug metabolism pathway gene set. ConclusionsBioinformatics methodologies are able to efficiently analyze microarray data and extract its underlying information,provide novel insights for major molecular events and shift of cell signaling pathway during pulmonary fibrosis progression,and furthermore,finding molecular markers for early diagnosis and therapeutic targets.