Augmented activation of microglia and astrocytes in the brain of aged PGRN-deficient mice. (A) Activation of microglia and astrocytes in PGRN-deficient mice. Hippocampal, cortical, and thalamic sections from 18-mo-old WT and PGRN-deficient (KO) mice (n = 6) were immunostained using antibody against CD68 or GFAP. (B) Activated CD68⁺ and GFAP⁺ cells were expressed as cells per square millimeter within indicated regions of both cerebral hemispheres of each animal. Results are means ± SEM from three independent experiments. *, P < 0.01 using the Student’s t test. Bar, 80 µm.