Fig. 4

Effects of PD-1/PD-L1 overexpression and knockdown on ICH-induced microglia polarization and STAT1 phosphorylation. a ICH rats accepted intracerebroventricular injection of pDNA or siRNAs as indicated. Sections were stained for CD16/CD11b (pro-inflammatory microglia marker) or CD206/CD11b (anti-inflammatory microglia marker). Percentage of CD16-positive cells or CD206-positive cells was shown in b and d and representative images were shown in c and e. Scale bar = 64 μm. In b and d, data are expressed as mean ± SEM, n = 6. Triple asterisks indicate p < 0.001 vs. sham group; single pound sign indicates p < 0.05, double pound signs indicate p < 0.01 vs. ICH + vector group; single ampersand indicates p < 0.05, double ampersands indicate p < 0.01 vs. ICH + control siRNA group. f Sections of ICH + PD-1 overexpression + PD-L1 overexpression group were stained for PD1/CD16/CD206. White arrows point to CD206-positive cells with high fluorescence intensity of PD-1, and purple arrows point to CD16-positive cells with low fluorescence intensity of PD-1. Scale bar = 64 μm. g Western blot analysis and quantification of the phosphorylation level of STAT1. The mean values of the protein levels in the sham group were normalized to 1.0. Data are expressed as mean ± SEM, n = 6. Double asterisks indicate p < 0.01, triple asterisks indicate p < 0.001 vs. sham group; double pound signs indicate p < 0.01, single ampersand indicates p < 0.05. h Western blot analysis and quantification of the phosphorylation level of STAT1. The mean values of the protein levels in the ICH group were normalized to 1.0. Data are expressed as mean ± SEM, n = 6. Double asterisks indicate p < 0.01 vs. ICH + vector group; single pound sign indicates p < 0.05, double pound signs indicate p < 0.01 vs. ICH + control siRNA group