IL10 and acute respiratory distress syndrome: The results demonstrated that the total number of lung macrophages (Maker, F4/80 and CD11b) was significantly reduced in UC-MSCs-treated ALI mice, but the IL-10 positive lung macrophages (Maker, IL-10) were up-regulated (Fig. 3a,b, p < 0.05), indicating that UC-MSCs modulate the immune response of lung macrophages in ALI mice by promoting lung macrophages to secret more IL-10 to protect ALI mice.