Fig. 3
Preconditioned MSCs drive M2 polarization in the presence of IL-4. Unstimulated or preconditioned MSCs were co-cultured with macrophages (ratio 1:2) in the presence of 20 ng/ml IL-4 for 24 h. After cell separation by autoMACS, macrophages were used for flow cytometric analyses. In some experiments, MSCs were placed in transwell chambers (TW). a The expression of the surface markers CD86 and CD206 as well as intracellular iNOS expression in macrophages was quantified by flow cytometry. Percentage of positive cells is depicted. For iNOS expression, the mean fluorescence intensity is additionally displayed. n = 7, *p < 0.05 vs. macrophages cultured alone (M2); #p < 0.05. b Levels of IL-10 in cell culture supernatants were measured by ELISA. NO2 concentrations were quantified by Griess assay. Results are representative for five independent experiments. *p < 0.05 vs. macrophage control (M2); #p < 0.05, &p < 0.01. IL interleukin, M macrophage, MSCs mesenchymal stem cells, iNOS inducible nitric oxide synthase, NO2 nitrite