Fig. 4.

Aged APOE2/3/4 KI animals exhibit different levels of C1q protein accumulation in the hippocampus. (A–C) Representative images from C1q immunohistochemistry in the 9-mo-old hippocampus from APOE2 (A), APOE3 (B), and APOE4 (C) homozygous KI animals. (D) In the 9-mo-old hippocampus, C1q accumulation is significantly reduced in APOE2 KI animals compared with APOE3 and APOE4 KI animals. n = 4 mice per group. (E) In the 18-mo-old hippocampus, C1q protein accumulation is significantly reduced in APOE2 KI hippocampus and significantly increased in APOE4 KI hippocampus compared with APOE3 KI hippocampus. n = 4 mice per group. ***P < 0.001 (one-way ANOVA). Results are quantified and graphed ±SEM. [Scale bar, 250 μm (A–C).]