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. Author manuscript; available in PMC: 2018 Jul 19.
Published in final edited form as: Neuron. 2017 Jul 6;95(2):341–356.e6. doi: 10.1016/j.neuron.2017.06.020

Figure 8. Microglia re-establish region specific phenotypes after ablation and repopulation.

Figure 8

A – Microglial distribution in brain sections from CX3CR1EGFP/+ mice after 2 weeks treatment with CSF1R antagonist PLEX5622 (top panel, PLEX) or 2 weeks of PLEX5622 treatment followed by a 21-day repopulation period (bottom panel, PLEX +21d). Dashed white lines indicate boundaries of VTA, SNc, and SNr. B – Example dying microglial cell in brain sections from CX3CR1EGFP/+ mice after 1 week of PLEX5622 treatment. Red arrow highlights cell’s pyknotic nucleus. C – High magnification images of microglial branching structure in brain sections from PLEX ablated/repopulated mice. 1 – NAc, 2 – VTA, 3 – SNc, 4 – SNr. Scale = 5 μm. D – Microglial density in Control (N = 3 mice), PLEX ablated (N = 4 mice), and PLEX ablated/repopulated mice (N = 3 mice). 2-way ANOVA; main effect of treatment, F(2,28) = 1035, P < 0.00001; main effect of brain region, F(3,28) = 261, P <0.00001; treatment x brain region interaction, F(6,28) = 56, P <0.00001. E – Microglial tissue coverage in Control and PLEX ablated/repopulated mice. 2-way ANOVA; main effect of brain region, F(3,16) = 275, P < 0.00001; main effect of treatment F(1,16) = 25, P = 0.0002; treatment x brain region interaction, F(3,16) = 11, P = 0.0004. F – Microglial density after genetic microglial ablation and repopulation using 4HT-treated CX3CR1CreER-iresEYFP;Rosa fs-DT/fs-DT mice. 2-way ANOVA (performed using raw density values for DT ablated/repopulated mice, Fig. S8F); main effect of treatment, F(2,42) = 119, P < 0.00001; main effect of brain region, F(3,42) = 11, P = 0.00002; treatment x brain region interaction, F(6,42) = 5, P = 0.002. N = 2 control mice, 4–9 ablated mice, 4 DT ablated/repopulated mice. G – Lysosome content of VTA and SNr microglia in brain sections from PLEX ablated/repopulated mice. * P < 0.002 VTA vs. SNr. N = 3 mice. H – Response of representative VTA and SNr microglia to hyperpolarizing and depolarizing current injection (left; red trace = injection of 5pA) or stepping to holding potentials from −120 mV to +10 mV (right). I – Average I–V curves from all recorded cells. 2/9 VTA microglia (22%) and 8/13 SNr microglia (62%) displayed voltage-activated conductances (Kv+). J – Magnitude of Kv currents estimated as in Fig. S2E. Filled circle corresponds to SNr cell shown in H. See also Figs. S7–8.