The effect of sex on cerebral microvessels. FFPE sections of mouse brain were stained for microvessels using collagen IV as a marker. Each slide was subsequently scanned using the Aperio ScanScope and analyzed using the microvessel algorithm feature of the associated ImageScope software, drawing regions of interest around the hippocampus and cortex of each section. Representative images for each brain region are shown for both female (a, c) and male (b, d) mice. (e) Vessel density was similar in males and females in the hippocampus, while females had a higher density in the cortex. (f) Vessel perimeter was not significantly different between females and males in either brain region tested. (g) The lumen area trended larger in the males than the females in the hippocampus. (h) Wall thickness was slightly thinner in males compared with females in both brain regions. Vessel walls were thicker in the hippocampus than the cortex of female mice. N = 6/sex. The distribution of data was evaluated by a Shapiro-Wilk test for normality (e, p = 0.017, f, p = 0.23, g, p < 0.0001, h, p = 0.425). Vessel density and lumen are were subsequently analyzed with a Mann-Whitney U test for nonparametric data. Vessel perimeter and wall thickness were subsequently analyzed by ANOVA.