Cerebral Resistance Artery Histological Remodeling After Training—Sex Differences

<b>Background</b>: Chronic exercise has been linked to positive effects on cognitive function and brain health. The aim of our study was to investigate how exercise affects cerebral resistance artery morphology, with an underlying focus on potential sex differences. <b>Methods</b>: Wistar rats were divided into male exercising (M.Ex; <i>n</i> = 6), female exercising (F.Ex; <i>n</i> = 5), male sedentary (M.Sed; <i>n</i> = 5), and female sedentary (F.Sed; <i>n</i> = 5) groups. After a 12-week swimming program, histological examinations of the intracerebral and pial arterioles were performed. SMA-DAB (smooth muscle actin) and resorcin-fuchsin (elastica) stained brain coronal sections were used for quantitative colorimetric analysis. <b>Results</b>: Investigating the effect of exercise, we found that in both pial and intracerebral arterioles, the elastic fiber density increased in both female and male exercising animals compared to the sedentary groups (<i>p</i> < 0.05 (M.Sed vs. M.Ex); <i>p</i> < 0.0001 (F.Sed vs. F.Ex)). As sex differences, we found that in female animals' pial arterioles, the density of elastic fiber was increased compared to the male exercising group (<i>p</i> < 0.001 (M.Ex vs. F.Ex)). In pial arterioles, the smooth muscle density was higher in the male sedentary animals (<i>p</i> < 0.01 (M.Sed vs. F.Sed)); in intracerebral arterioles, the smooth muscle density increased with exercise in the male animals as well (<i>p</i> < 0.0001 (M.Ex vs. F.Ex)). <b>Conclusions</b>: Our results demonstrate that the increase in vascular elasticity is more pronounced overall in female animals.