Sex Differences in Vascular Reactivity to Angiotensin II During the Evolution of Myocardial Infarction

The influence of sex on the vascular response during the progression of myocardial infarction (MI) has not been extensively studied. In this work, we analyzed the differences of the vasoconstriction induced by angiotensin II (Ang II) in the absence and presence of valsartan (200 nM) on the aortic rings of male and female Wistar rats at 2, 4, 24, and 48 hours and 1, 2, 3, and 4 weeks after induction of MI. In the aortic rings of males, an increase was observed in the contractile response that lasts up to 4 weeks; on females, this effect is diminished since 48 hours until reaching sham group values at 2 weeks of coronary occlusion. The incubation of valsartan generated greater reduction on vasoconstriction in males than females. In relation to the determination of infarct areas, we found them between 30% and 40% in all experimental groups. In addition, the index of hypertrophy was determined and no significant changes were observed in female rats, while in males we reported an increase at 2, 3, and 4 weeks. In conclusion, we found differences in vascular reactivity due to sex, as well as on the response of Ang II via AT1 during the evolution of MI.