Fig. 5

Enhanced polarization towards M2 macrophages is attributed to their phagocytosis of SPION-MSCs. A RAW264.7 cells were added to a Transwell system with MSCs or SPION-MSCs for 24 h in the presence of LPS (100 ng/ml). mRNA levels of M1 markers (iNOS) and M2 markers (IL-10 and Arg-1) were detected by qRT-PCR. B Protein levels of iNOS and Arg-1 determined by western blots. C, D Representative flow cytometry plots showing the percentages of M1 (iNOS + CD206 −) and M2 (iNOS − CD206 +) phenotypes in LPS-stimulated peritoneal macrophages after culturing with MSCs or SPION-MSCs for 48 h. E RAW264.7 cells with MSCs, SPION-RHB-MSCs or SPION-RHB-L929 cells were directly incubated for 12 h, 24 h or 48 h in the presence of LPS (100 ng/ml). MSCs or L9292 cells: macrophages = 1:4. Representative images of MSCs incubated with CM-Dil, MSCs incubated with SPION-RHB and L929 cells incubated with SPION-RHB. F Representative flow cytometry plots showing the percentages of positive cells that engulfed MSCs, SPION-RHB-MSCs or SPION-RHB-L929 cells (F4/80 + PE +). G, H Engulfing MSCs and percentages of M2 (F4/80 + PE + CD206 −) and M1 ((F4/80 + PE + iNOS +) phenotypes in the LPS-stimulated peritoneal macrophages. Data with error bars are presented as the mean ± SD. Each panel is a representative experiment of at least three independent biological replicates. Scale bars, 50 mm. *p < 0.05, **p < 0.01, ***p < 0.001 as determined by unpaired Student’s t-test