FN1 and idiopathic interstitial pneumonia: Compared with the control group, the ratio of lung W/D and the contents of HYP were significantly increased in the IPF group (P < 0.01, Figures 1(a) and 1(b)), the expression of Col IV and FN was markedly increased in the IPF group, and positive cells are stained brownish yellow (P < 0.05, Figures 1(c) and 1(d)).