Figure 2.

Microglial BDNF deficiency reduces microglial density and their proliferation. A, Experimental timeline for daily intraperitoneal BrdU injections in Cx3cr1^creERT2 x Bdnf ^flox/flox mice, given 1–4 d after CO or TAM treatment, with mice killed 3 d after the last BrdU injection. B, Confocal images of IBA1^pos and BrdU^pos cells in the dentate gyrus of Cx3cr1^creERT2 x Bdnf ^flox/flox mice. C, D, Quantification of total IBA1^pos microglia (C; t₍₁₂₎ = 3.20, p = 0.0077) and newborn IBA1^posBrdU^pos microglia (D; t₍₈₎ = 6.78, p = 0. 0001) in the dentate gyrus. E, Experimental timeline for Cx3cr1^creERT2 x Bdnf ^flox/flox mice treated with CO or TAM and killed 6, 14, or 35 d later. F, Quantification of IBA1^pos microglia in the dentate gyrus at 6, 14, or 35 d post-corn oil or tamoxifen administration (F_(3,40) = 11.74, p < 0.0001; CO vs TAM 6 d, p = 0.046; CO vs TAM 14 d, p = 0.0001; CO vs TAM 35 d, p = 0.0002). G, Experimental timeline for wild-type mice treated with either corn oil or tamoxifen once daily for 5 d and killed 6 d after the fifth and final treatment. H, Quantification of IBA1^pos microglia in the dentate gyrus of wild-type mice (t = 0.65, df = 8, p = 0.53). Data represent the mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001. Statistical tests: unpaired Student's t test, C, D, H; one-way ANOVA with Bonferroni post hoc comparison test, F. Small circles represent individual mice.