Bone marrow mesenchymal stem cells induce M2 microglia polarization through PDGF-AA/MANF signaling

Figure 6 In vivo analysis of M1 and M2 polarization markers after cerebral I/R injury with bone marrow mesenchymal stem cell treatment. A: Immunohistochemistry analysis of iNOS expression in the microglia/macrophages of the ischemic brain after 24 h of MCAO. Representative images of the indicated brain double stained with Iba1 (green) and iNOS (red), with DAPI (blue) as a nuclear counterstain, are shown. ^bP < 0.01 vs I/R and I/R + PBS groups; ^dP < 0.01 vs I/R + BMSCs and I/R + BMSCs-NC groups. Scale bar = 50 μm. Arrows point to the iNOS⁺/Iba1⁺ cells; B: qRT-PCR analysis of iNOS expression in acute ischemic stroke rat brains; C: Immunohistochemical analysis of Arg1 expression in the microglia/macrophages of ischemic brains. Representative images of the indicated brain double stained with Iba1 (green) and Arg1 (red), with DAPI (blue) as a nuclear counterstain, are shown. Scale bar = 50 μm. Arrows point to the Arg1⁺/Iba1⁺ cells; D: qRT-PCR analysis of Arg1 expression in rat brains at 24 h after MCAO. ^bP < 0.01 vs Sham group; ^dP < 0.01 vs I/R and I/R + PBS groups; ^fP < 0.01 vs I/R + BMSCs and I/R + BMSCs-NC groups. The values are expressed as the mean ± SD (n = 6). I/R: Ischemia/reperfusion; PBS: Phosphate-buffered saline; BMSCs: Bone marrow mesenchymal stem cells; BMSCs-NC: Negative control-transfected BMSCs; BMSCs-siMANF: MANF siRNA-transfected BMSCs; iNOS: Inducible nitric oxide synthase; Arg-1: Arginase-1; Iba1: Ionized calcium-binding adapter molecule; DAPI: 4'6-diamidino-2-phenylindole.