Fig. 4

SLDS promotes M2 microglial polarization in vitro. The M1 phenotype was induced using LPS (50 ng/ml) plus IFN-γ (20 ng/ml) and the M2 phenotype was induced using IL-4 (20 ng/ml) plus IL-13 (20 ng/ml). The role of SLDS on cell death of primary microglia (a) and primary neurons (b); n = 12 per group. c The role of SLDS in the cell death of primary neurons subjected to 1 h OGD exposure and subsequent 4-h reperfusion. n = 15 per group. d The role of SLDS in the cell death of primary neurons subjected to 1 h OGD and subsequent 24-h reperfusion. n = 12 per group. e Neuronal death was quantified by LDH release in primary neuron-microglia cocultures; n = 12 per group. f mRNA expression of M1 markers (CD16, iNOS) and M2 markers (CD206, Arg1) in primary microglia treated with salidroside or induction factors (or a combination of both). Vehicle was added to non-treated microglia (control); n = 3 per group. g Representative triple immunofluorescence staining of iNOS (green), Arg1 (red), and Iba1 (gray) in the different treatment groups. Vehicle was added to non-treated microglia (control). DAPI (blue) was used as a nuclear marker. Data are expressed as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, by one-way ANOVA and Tukey’s test