Fig. 3

Therapeutic interventions in injured lungs during cross-circulation. a Gross imaging of BAL fluid samples collected from injured lungs over 36 h of cross-circulation. b Periodic acid-Schiff staining of BAL fluid smears obtained from injured lungs. c Quantification of cells in BAL fluid samples. d Pepsin concentration, e pH, f total protein, and g exosome concentration in BAL fluid samples over 36 h of cross-circulation, Student’s t-test for Injured versus Control, *p < 0.001. h Mean cytokine expression levels in injured lungs, normalized as a percent of mean levels in control lungs, measured in BAL fluid between initiation of cross-circulation (0 h) and conclusion of cross-circulation (36 h). Cytokine concentrations (mean ± standard deviation) throughout 36 h of cross-circulation in Supplementary Fig. 5c. Surfactant replacement: i Bronchoscopic delivery of therapeutic surfactant into injured lung (arrow). j Bronchoscopic image demonstrating therapeutic surfactant delivered into airways within the injured lung. k Transmission electron micrograph (TEM) demonstrating abundant surfactant (arrows) within alveoli following delivery. Alveolar macrophage (star) and adjacent lymphocyte observed within the same alveoli. l Dynamic compliance (Cdyn) of injured lungs pre- and post-delivery of therapeutic surfactant over the first 18 h of cross-circulation. m Alveolar recruitment: before recruitment (atelectatic) and after recruitment (recruited). Arrow and dotted line indicates a region of recruitment. n Silver reticulin staining of collapsed consolidated lung, and recruited lung with open alveoli. o Peak inspiratory pressure (PIP) of injured lungs throughout 36 h of cross-circulation. All graphs represent data from n = 8 lungs. All values represent mean ± standard deviation