Figure 6: Exposure to conditioned media from MSCs or EVs induces a shift in macrophage polarization in vitro to the M2 rather than the M1 phenotype. Alveolar macrophages (105 cells per well) were collected from (a) Cp and ARDSp or (b) Cexp and ARDSexp mice. Cells were cultured in regular conditions (Cp, Cexp, ARDSp-SAL, and ARDSexp-SAL) or with conditioned media obtained from MSCs (105 cells per well) either unstimulated or stimulated with serum (serum) or extracellular vesicles derived from ARDSp or ARDSexp mice for 24 h. Relative gene expression of iNOS, IL-1β, IL-6, IL-10, arginase, and TGF-β was calculated as a ratio of average gene expression compared to expression of the housekeeping gene 36B4 and presented as fold changes relative to the Cp or Cexp group (alveolar macrophages from Cp or Cexp animals cultured with conditioned media from unstimulated MSCs). Results are presented as of alveolar macrophages pooled from 3 mice/group. All measurements were performed in triplicate. Significantly different from the corresponding C group (). Significantly different from the corresponding ARDS group (). #Significantly different from the corresponding MSC group ().