(A) Representative immunofluorescence images of MBP staining, marker for myelin, in RA, BPD, vehicle (PBS)-injected BPD mice, MSC-CM EXO 25 wks and MSC-CM EXO 30 wks-injected BPD mice (I, II, III, IV, V), to quantitate myelin loss in BPD and vehicle (PBS)-injected BPD mice (II, III) and restoration of myelination after MSC-CM EXO 25 wks (IV) and MSC-CM EXO 30 wks (V) injections. This evidence concerns the gene MBP and bronchopulmonary dysplasia.