Fig. 3

H&E results. A, B Light photomicrographs of CG showing: A Patent alveoli (PA) and thin classical interalveolar septa (S). B folded bronchiolar epithelium, BV; blood vessel. B Alveoli lined with flat squamous type I pneumocytes (arrow) and bulging cuboidal type II cells (arrowhead). Thin interalveolar septa (S) with only few interstitial cells (IS) are also seen. C, D light photomicrographs of HG revealing: C Most alveoli are collapsed (CA) with thick interalveolar septa (S) and cellular infiltration (I). PA; a patent alveolus. D Collapsed alveoli (CA), thickened septa (S) and extravasated red blood corpuscles in the alveolar lumen (notched black arrow) and in the septa (white arrow). Few type I pneumocytes (thin arrow) and many type II pneumocytes (arrowhead) are also seen. B bronchiole. E, F light photomicrographs of CFM-TG showing: E: Collapsed alveoli (CA), thick septa (S) and cellular infiltration (I). B a bronchiole with desquamated cells in its lumen. F Thickened septa (S) with multiple interstitial cells having vacuolated cytoplasm (arrow). Most of the alveolar lining cells have rounded nuclei (arrowhead). G, H Light photomicrographs of SC-PG showing: G Thin interalveolar septa (S) separating the patent inflated alveoli (PA). H Flat type I pneumocytes (arrow) and large bulging eosinophilic type II (arrow head). S; thin interalveolar septum, PA; a patent alveolus. I, J light photomicrographs of SC-TG showing: I Mildly thickened Interalveolar septa (S) between the patent alveoli (PA). J Some septa are thin (S), others are mildly thickened (star). Some interstitial cells show vacuolation (thick arrow). Flattened type I (thin arrow) and few type II (arrowhead) are also seen. K, L light photomicrographs of Unt-G showing: K Collapsed alveoli (CA) and thickened interalveolar septa (S). L Thick interalveolar septa (S) showing vacuolated interstitial cells (arrow). Most of the cells show deeply-stained nuclei (N). H&E stain, scale bar (A, C, E, G, I, K) 200 µm, (B, D, F, H, J, L) 50 µm. n = 10 in all groups