Fig. 8

Sexually divergent, age-related hippocampal C1q protein expression. Protein expression of compliment 1q isoforms C1qA (a) and C1qC (b) were induced with age and to a greater extent in females than males. Data is scaled to a mean value of 1 for young males. Boxes boundaries are the 25th and 75th percentiles, with median denoted by the bar and error bars at the 10th and 90th percentiles. Two-way ANOVA (age × sex), ***p < 0.001, *p < 0.05 Student–Newman–Kuels post hoc, n = 6/group. Solid comparison lines denote age-related changes with a sex, and dashed comparison lines are sex-related differences within an age. In sagittal brain sections qualitatively increased immunoreactivity for C1q was evident with aging across the brain in both female and male mice (c–f). Detail regions of 24-month-old female (g) and male (h) mice show patches of C1qa-positive signals throughout the brain neuropil. Boxed area shows further magnified image to show the details of C1qa-positive patches. Scale bars 1 mm. C1q immunoreactivity was co-localized with Iba1 immunoreactivity in young females (i), old females (j), young males (k), and old males (l) demonstrating microglial expression. Scale bars 20 μm wide view, 5 μm zoomed view