University of Louisville
Neuroprotective Effects of Dietary Phytoestrogens in an Aging Rodent Model
Institution
University of Louisville
Faculty Advisor/ Mentor
Cynthia Corbitt; Monica Unseld
Abstract
Many women approaching menopause are likely to consider using phytoestrogen (plant-made estrogen) supplements for relief of menopausal symptoms such as hot flashes because these products are viewed as being 'natural'. Because they are not regulated by the FDA, little research has investigated effects of these supplements, especially on the brain. Studies on estrogens have found them to be potentially neuroprotective against age-related deficits in cognition and in cases of ischemic stroke. We are testing the hypothesis that phytoestrogens are neuroprotective for memory using an aging rodent model. Estrous cycles of young adult and middle-aged retired breeder rats were assessed so that only regularly cycling young rats and irregularly cycling middle-aged rats (i.e., those exhibiting evidence of brain aging) were used in the study. These rats (n=48) were ovariectomized to eliminate ovarian estrogen, then were fed a diet either with or without soy phytoestrogens for 3 weeks before being tested in object and placement memory trials over the course of 3 weeks. These tests take advantage of a rodent’s attraction to novelty, so if a rat remembers an object it should spend less time investigating it than it will a novel object. We also tracked food intake and body weight over the course of the experiment. We predict that the middle-aged rats will exhibit deficits in memory compared to the young adult rats, but that soy phytoestrogens in the diet will attenuate these deficits.
Neuroprotective Effects of Dietary Phytoestrogens in an Aging Rodent Model
Many women approaching menopause are likely to consider using phytoestrogen (plant-made estrogen) supplements for relief of menopausal symptoms such as hot flashes because these products are viewed as being 'natural'. Because they are not regulated by the FDA, little research has investigated effects of these supplements, especially on the brain. Studies on estrogens have found them to be potentially neuroprotective against age-related deficits in cognition and in cases of ischemic stroke. We are testing the hypothesis that phytoestrogens are neuroprotective for memory using an aging rodent model. Estrous cycles of young adult and middle-aged retired breeder rats were assessed so that only regularly cycling young rats and irregularly cycling middle-aged rats (i.e., those exhibiting evidence of brain aging) were used in the study. These rats (n=48) were ovariectomized to eliminate ovarian estrogen, then were fed a diet either with or without soy phytoestrogens for 3 weeks before being tested in object and placement memory trials over the course of 3 weeks. These tests take advantage of a rodent’s attraction to novelty, so if a rat remembers an object it should spend less time investigating it than it will a novel object. We also tracked food intake and body weight over the course of the experiment. We predict that the middle-aged rats will exhibit deficits in memory compared to the young adult rats, but that soy phytoestrogens in the diet will attenuate these deficits.