Fig. 1.

MSCs ameliorate LPS-induced ALI. a Survival curve of mice treated with LPS and MSCs. b CCL4, CCL3, IL-6, and IFN-γ concentrations in BALF at 3 and 7 days after LPS or LPS/MSC treatment; data are means ± SEM (n = 3 per group). c Numbers of neutrophils in BALF in different groups; data are means ± SEM (n = 3 per group). d H&E staining of lung sections at PBS group, 3 and 7 days after LPS and LPS/MSC treatment. Red arrows indicating cell infiltration in the alveolar interstitium and thickening of the alveolar interstitium. On day 3 after LPS treatment, many immune cells, especially neutrophils, infiltrated into the alveolar interstitium, while thinner alveolar interstitium and reduced immune cell infiltration were observed on day 3 after MSC treatment (damage phase). On day 7 after LPS and MSC treatment, the alveolar interstitium became thinner than day 3, and ALI had recovered almost completely at day 7 (recovery phase). *P < 0.05, **P < 0.01, ***P < 0.001 unpaired Student’s t test