Fig. 3

VPA promotes microglia polarization toward M2 and alleviates microglia-mediated inflammatory response. a, b The double immunohistochemical staining for the microglia (Iba1+) and the M1-associated marker (CD16+) or the M2-associated marker (CD206+) 7 days after the SCI was assessed. The microglia labeled with the M1 (CD16+) increased after the SCI but significantly decreased following the VPA treatment. The M2 (CD206+) increased following the VPA treatment. Representative photomicrographs of the CD16 or the CD206-positive microglia are shown. Enlarged images of boxed areas are shown on the right. c Western blot analysis showed that the M1 phenotype microglial proteins (CD16 and Iba-1) were significantly inhibited, whereas the M2 phenotype microglial protein (CD206) increased following the VPA treatment. d The VPA treatment significantly decreased the SCI-induced enhancements of TNF-α, IL-1β, IL-6, and IFN-γ (P < 0.05). Values were expressed as mean ± standard deviation (n = 6 per group). N.S., P > 0.05, *P < 0.05, **P < 0.01. Scale bars = 50 μm