Osteopontin Augments M2 Microglia Response and Separates M1- and M2-Polarized Microglial Activation in Permanent Focal Cerebral Ischemia

Figure 1

OPN treatment shifts the M1/M2 balance towards an M2 phenotype. (a) Arg1+ M2 cells (red) dominated the infarcted area in OPN-treated rats, whereas iNOS+ M1 microglia were found predominantly in vehicle-treated animals (green). (b) M1 (iNOS-expressing) microglia and M2 (Arg+, CD206+, or Ym1+) microglia in the infarcted area after photothrombosis expressed as M1/M2 ratio. Ten days after photothrombosis, the ratios of M1/M2 microglia were significantly decreased in OPN-treated animals compared to vehicle-treated controls, suggesting an increase in M2 polarization. (c) Close-up of microglia expressing either M1 (iNOS) or M2 (Arg1) markers (upper row), or expressing both markers (lower row). Scale bars represent 40 μm in (a) and 10 μm (c). All graphs show mean and SD; .

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