Expression patterns of hyperoxia-responsive mRNAs and functional analysis. Total RNA was isolated and RNA quality was confirmed. In total, 12 samples were used for analysis of mRNA expression; 2 samples for each normoxia group at time points of P1, P14, and P29; and 3 samples for each hyperoxia-treated group at time points P14 and P29. Gene expression profiling was performed using the Affymetrix GeneChip Mouse Genome 430 2.0 Array. Expression patterns of hyperoxia-responsive mRNAs and corresponding gene ontology mapping were performed. (A) 8 expression patterns in 3 groups represented by color heat maps and bar graphs (x axis indicating the 3 time points, y axis indicating the relative expression value of group probes). Red represents increased expression and green represents decreased expression in the depicted heat maps. The relative expression values in each time point are the ratios normalized against those in the P1 group. Group A: P29-RA vs P14-RA, Group B: P14-O2- treated vs P14-RA, Group C: P29-O2-treated vs P29-RA (B) Analysis of enrichment for GO biological process categories for 8 expression patterns. Top 10 GO terms (ranked by count number) with p < 0.05 are listed.