Effects of soy isoflavone on cardiac dysfunction in geripause-like rats: comparisons with hormone-replacement therapy

Abstract

Background Cardiovascular diseases are a primary cause of morbidity and mortality worldwide. The prevalence of cardiovascular disease as well as inflammation in postmenopausal women is higher than premenopausal women. Objective The present study investigated cardiac dysfunction elicited by estrogen deprivation and aging and assessed a possible beneficial impact of isoflavones compared with estradiol-replacement therapy. Materials and methods Forty aged female rats were equally divided into four groups. Except for sham-operated animals in group 1 (negative control), all other rats were ovariectomized. One month after surgery, animals were assigned to groups 3 and 4. Rats in the former group were treated with 17β-estradiol, 100 μg/kg, intramuscular, every other day. Animals in group 4 were administered soy isoflavones (SIF), 40 mg/kg/day orally. Treatments continued for 1 month. Results and conclusion Compared with control rats, ovariectomized animals showed cardiac dysfunction and inflammation evidenced by dyslipidemia and elevated serum creatine phosphokinase and lactate dehydrogenase activity, angiotensin II, cardiac malondialdehyde and nitric oxide levels, and serum tumor necrosis factor-α and interleukin-6 levels. These impacts were concurrent with significant decreases in cardiac catalase activity and total antioxidant capacity. Treatment with SIF was more effective in mitigating inflammation and cardiac dysfunction compared with estradiol-replacement therapy. Histopathological examination of heart tissues supports these biochemical findings. SIF are a safe and well-tolerated alternative to estradiol for improving cardiac dysfunction elicited by menopause and age.