Introduction: Regular moderate exercise improves cardiovascular risk profile, but recent data suggest that such benefit might regress in some highly trained athletes. Men and women share classic risk factors, but their relative weight may diverge. As for exercise, the impact of sex in the response to extreme training remains controversial.
Aim: To assess the impact of sex on vascular remodeling after high intensity training in an animal model.
Methods: Wistar rats (20 male, 15 female) underwent intense (INT, 60min 60cm/s) treadmill training for 16 weeks. Sedentary rats (SED, 20 male, 18 female) served as controls. Histological analyses (fibrosis, morphometry, superoxide production [DHE]) were performed in thoracic aorta and left carotid. Vascular reactivity to carbachol (Cch) and phenylephrine (Phe) was studied in aortic rings. Endothelial dysfunction biomarkers von Willebrand factor (vWF) and soluble intercellular adhesion molecule-1 (sICAM-1) were quantified in plasma.
Results: INT exercise increased fibrosis in the tunica media of the aorta and left carotid of both male and female rats (Fig. A), with no further structural changes. In SED animals, female rats showed enhanced endothelial function (increased Cch vasodilatation, reduced Phe vasoconstriction) as compared to male rats. INT exercise improved endothelial function in male, but not female rats (Fig. B). In SED animals, vWF and sICAM-1 were increased in male compared with female rats. Exercise reduced siCAM-1 levels in male, but not female rats (Fig. C). Oxidative stress was increased in male, but reduced in female rats after INT exercise.
Conclusions: SED female rats show a better endothelial function than males. After INT exercise, however, endothelial function improved in males, but not in females, thereby eliminating sex differences. Tunica media fibrosis occurred in both sexes. Our results support sex-associated differences in vascular remodeling after extreme exercise in a murine model.