Fig. 2

Microglial ultrastructure is changed by proximity to fAβ plaques. a EM image from a WT control animal showing oval shaped IBA1-positive microglial cell body contacting extracellular space pocket and axon terminal in the ventral hippocampus CA1. b EM image of a plaque-associated microglial cell body that contains lipidic inclusions, lipofuscin granule, and lysosome, as well as contacting extracellular space pocket. c Microglial processes in an ultrastructurally healthy subregion of APP^Swe-PS1Δe9 mouse model, touching or encircling various types of synaptic elements. d dendrite, Ex extracellular space pocket containing debris, Lg lipofuscin granule, Lip lipidic inclusion, Ly lysosome, m microglia, mt mitochondrion, s dendritic spine, t axon terminal. d Change in microglial cell body area of WT controls compared to APP^Swe-PS1Δe9 animals. e Change in microglial cell body area in APP-H, APP-D, and APP-P subregions. f Change in the microglial process circularity in WT and APP^Swe-PS1Δe9 animals. g Change in the microglial process solidity in WT and APP^Swe-PS1Δe9 animals. n = 50 processes per condition for APP-H, APP-D, and APP-P and 70 processes per animal for WT animals, n = 7–15 cells per condition for all conditions, and data was collected from N = 3–4 animals per condition. All error bars are mean ± SEM. WT levels are shown on the subregion graphs by a gray horizontal line. *p < 0.05 difference from WT, ~p < 0.05 difference from APP-H