The effects of ovariectomy and soy diet on vascular function in female C57BL6 mice

Abstract

As people begin to live longer, studying age-related disease becomes more important. Age is a major risk factor for Alzheimer’s disease (AD), a prominent neurodegenerative disease, and cardiovascular diseases. Females develop AD at much higher rates than males and all signs point to sex hormones as a cause. Estrogen drastically decreases post menopause, and it has been suggested that estrogen deficiency is a contributing factor to the sex differences seen in AD and other age-related diseases. The vascular system plays an important role in aging. A characteristic of aging in the vascular system is stiffening of larger arteries. Large artery stiffening is detrimental because it leads to an increase in pulse pressure and stress on the microvasculature. Decreased estrogen activity results in increased production of reactive oxygen species, causing tissue damage and dysfunction. Soy also has been seen to be a protective factor against symptoms of age-related disease due to its role as a phytoestrogen, thus showing the potential importance of soy. This study aimed to explore the effects of estrogen depletion post menopause and the effects of a soy diet in relation with estrogen loss. We utilized a mouse model of ovariectomies to mimic estrogen loss post menopause and studied cognitive function, motor coordination, and vascular function. We found that soy supplementation positively affected cognition but not motor coordination, while loss of estrogen had no effect on both cognition and motor coordination. Arterial stiffness was not impacted by either ovariectomy or soy, but nitric oxide mediated dilation was impaired with estrogen loss and was recovered with soy diet supplementation. Altogether, these results suggest that even with loss of estrogen, soy could play a protective role in endothelial function while it does not affect cognitive function, motor coordination or in vivo large artery stiffness.