FIGURE 5.

Low-fat diet with caloric restriction reduces white matter microglia activation during aging. (A) Brain sections of 6- and 24-month-old mice on different diets and regimes were immunostained for Iba1 and Mac-2, and counterstained with cresyl violet. LFAL, low-fat diet ad libitum; HFAL, high-fat diet ad libitum; LFRW, low-fat diet with running wheel; HFRW, high-fat diet with running wheel; LFCR, low-fat diet with caloric restriction; HFCR, high-fat diet with caloric restriction. (B) Quantification of conditions depicted in the top panel of (A). The expression of Iba1 and Mac-2 increased during aging in both HFAL and LFAL groups (n = 3–7 mice, mean ± SEM is depicted, Mann–Whitney test, ns, not significant, ^∗p < 0.05, ^∗∗p < 0.01). (C) Quantification of conditions depicted in the bottom panel of (A). Compared to the LFCR group, the expression of Iba1 was significantly higher in HFAL, HFCR, LFAL, and LFRW mice. Mac-2 was significantly higher expressed in HFCR, LFAL, and LFRW mice (n = 3–7, Mean ± SEM, Mann–Whitney test, ^∗p < 0.05, ^∗∗p < 0.01). (D) Tissues from animals on different diets and regimes (LFAL, HFAL, LFRW, HFRW, LFCR, and HFCR) were immunostained for Dectin 1 and CD16/CD32 and counterstained with hematoxylin. (E) Dectin 1 and CD16/CD32 were significantly lower expressed in LFCR mice exclusively (n = 4–7 mice, mean ± SEM is depicted, Mann–Whitney test, ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001). Scale bar: (A,D) = 40 μm.