Figure 3: Histopathological constituents of BOOP lesion in specific staining. The representative picture showed the intraluminal plugs of loose connective tissue that occlude bronchioles in H&E stain (a). A large mount accumulation of collagen matrix was sawn cherry in picrosirius red stain (b) and strongly blue in OPIC stain (c) at the evaginated BOOP lesion. The elastic fibril revealed disruption and fragmentation in peribronchial alveolar septa ((c), arrow head) as compared to normal lung ((c) upright panel, arrow head). The proliferative cells of the intraluminal plugs and alveolar septa were identified as -SMA positive MFBs (d) and OPN positive cells (e). MMP-2 (f) and MMP-9 (g) seemed to be expressed actively at the margin of intraluminal plugs of bronchioles as macrophage and myofibroblasts. The results shown represent one of six replicates in each independent experiment demonstrating similar results ( versus normal group). ().