Fig. 2.

Light misroscopic examination. Control Group (H&E ×200): a Infiltration of polymorphonuclear neutrophil leukocytes into the lung alveoli. b Interstitial and intraalveolar edema. c Perivascular and/or intraalveolar hemorrhage. d Hyaline membrane formation. rBM-MSCs Group: a, c (H&E ×100); b, d (H&E ×200), showing histopathological signs as prominently decreased interstitial/intra-alveolar edema, perivascular and/or intra-alveolar hemorrhage and hyaline membrane formation. In contrast, the infiltration of PMNL was slightly diminished