Sex-related differences in vascular remodeling of sodium overloaded normotensive mice

Background and Aims: Primary hypertension affect about 20% of adults in developed societies and, associated with high salt intake, leads to vascular remodeling, an adaptive physiological response of blood vessels that driven by repair, inflammation, or cell growth, is but may contribute to vascular diseases over time. This study examined vascular remodeling in the aorta and cardiac arteries, focused on gender-specific responses to sodium overload. Methods and Results: Adult male and female C57Bl/6 mice were divided into six groups: control with filtered water (Cont M; Cont F), 1% NaCl for two weeks (Salt-2 M; Salt-2 F), and 1% NaCl for twelve weeks (Salt-12 M; Salt-12 F). Blood pressure (BP) and heart rate (HR) were measured using tail plethysmography, and metabolic cages recorded 24-hour water intake and urine output. Morphometric analysis of the aorta and cardiac arteries included assessments of elastic laminae and collagen fibers, using Weigert van Gieson and Picrosirius staining. No changes in BP and HR were observed. Sodium intake increased water consumption in both genders after two weeks, but only males showed increased urine output. Vascular responses differed: males exhibited delayed increases in aortic elastic lamellae, while females showed earlier changes. Elastic lamellae in cardiac arteries remained unchanged. Collagen deposition increased in aortic walls for both genders but decreased by 50% in male cardiac arteries. Males showed thick collagen fibers, while females had thin and thick fibers. Conclusion: High sodium intake caused arterial stiffness through distinct mechanisms in males and females, even in normotensive animals.