Fig. 4

Functional gene clusters and the lung volume response to LPS/MV. Principal component analysis (PCA) was used to group genes in each functional category. The Pearson correlation coefficient was used to measure the strength of the linear association between the generated PCA score for each category and lung volume (nVt and nEEV) in the LPS/MV group (n = 17) (a). PCA scores for the selected gene sets were compared amongst the three regions (R1, L2 and R4) in the LPS/MV (b) and LPS (c) group (n = 6 for R1 and L2, n = 5 for R4; Values are mean + SD). ^* p < 0.05, ^** p < 0.01, ^***p < 0.001 (compared to R4 for graph b & c). nVt: normalized tidal volume; nEEV: normalized EEV; MV: mechanical ventilation