Figure 2.

Effects of irradiation (IR) on gene expression in lung tissue. C57Bl/6NCr mice were exposed to 0 Gy (control), 5 Gy, or 17.5 Gy thoracic IR. Samples of lung tissue (n = 3 per dose and time point) were collected at intervals after IR and in control mice for microarray analysis. A) Pattern of differentially expressed genes (P < .05 by analysis of variance with post hoc Scheffe analysis) in lung tissue by microarray analysis by treatment comparison over time. All statistical tests were two-sided. B) Unsupervised hierarchical clustering of differentially expressed genes in lung between treatments. Lung treated with 17.5 Gy clusters with aged unirradiated specimens (green color coding of dendrogram and samples), lung treated to 5 Gy clustered with intermediate aged controls (blue), and young controls grouped separately (red). W = week.