Fig. 6

Microglia depletion reduced neurosphere growth in vitro. A1, A2 Experimental design for a neurosphere assay with conditional depletion of microglia. A1 Tissue origin: ipsi- or contralateral tissue blocks including the SVZ were separately isolated from P10 HI animals (HI ipsi, HI contra), or pooled from P10 sham animals (sham). A2 Depletion method: dissociated tissue blocks were exposed to three conditions, with either no antibody (control), addition of nonspecific toxic antibodies (IgG), or CD11b+ specific toxic antibodies (anti-CD11b). B Representative image of a Nestin+ DCX+ neurosphere after 6 DIC. C Representative images of Iba1+ microglia in HI ipsi cell cultures after 6 DIC. The anti-CD11b condition strikingly reduced Iba1+ cells. D Representative images from sham and HI ipsi cell cultures after 6 DIC. Less neurospheres were present in the anti-CD11b conditions. E Number of neurospheres after 6 DIC. In the control and IgG conditions, HI ipsi-derived tissue cultures produced more neurospheres than sham-derived, reflecting HI-induced proliferation and indicating no interference of unspecific toxic antibodies with cell growth. In contrast, anti-CD11b antibodies significantly decreased neurosphere numbers independent of tissue origin. F Data from E in comparison to microglial percentage at DIC6, showing a positive correlation between microglial proportions and neurospheres (r = 0.87, 95% CI 0.68–0.93). Individual data shown as dots; bars as mean with SD (error bar). One-way ANOVA with Holm-Sidak post hoc test, *p < 0.05, ****p < 0.0001 (Additional file 1: Table S3). Scale bar for B 50 μm, C 100 μm, D 200 μm