Fig. 3

Sustained microglia activation in the aged brain. a Activated microglia were quantified throughout the hippocampus of mice and expressed as percentage of hypertrophic microglia over total number of Iba-1 positive cells (***P < 0.001). b Microglia masks from the entorhinal cortex of young and aged mice, naïve controls, and after SI. Microglial cell bodies are shown in white, and every circular envelope has a random color. c Total number of microglia skeleton segments are decreased by age (***p < 0.0001). d Sholl analysis of the number of branches plotted as a distance from cell body (n = 17 to 33, microglial cells per experimental group). e Area under the curve of the Sholl curves depicted in D showed a lower number of branches along the microglial cell in young naive vs young SI (207 ± 34 vs 115 ± 13, ***p < 0.001) but no difference between aged naive and aged SI (57 ± 7 vs 60 ± 8, p = 0.89). Statistical analysis with Kruskall Wallis test and Holm-Sidak’s multiple comparisons test. Data were plotted as means ± SEM