Fig. 8

Age-associated reactive astrogliosis was microglia-independent. Adult (6–8 weeks old) and aged (16–18 months old) male BALB/c mice were provided diets formulated with vehicle or CSF1R antagonist (PLX5622) for 21 d. After 21 d, mice were sacrificed or provided vehicle diet for an additional 21 d to allow for repopulation of microglia. After 0 or 21 d of repopulation, hippocampal GFAP reactivity was measured by IHC. a Representative GFAP⁺ immunolabeling in the hippocampus of adult and aged mice. Scale bar represents 100 μm. b Density of GFAP⁺ astrocytes in the hippocampus with and without microglial depletion and repopulation (n = 10–12 mice / group). Similarly, a 1-mm coronal brain section was isolated from mice after 21 d microglial repopulation, RNA isolated, and gene expression analyzed by qPCR. Normalized mRNA expression of Gfap (c), S100b (d), and Vim (e) in the brain (n = 3 mice / group). Bars represent the mean ± SEM. Means with * are different from Adult Control (P < 0.05)