Early Ovarian Hormone Deprivation Increases Cardiac Contractility In Old Female Rats - Role Of Physical Training

Abstract

Physiological menopause occurs around 51 years of age. However, in some cases, menopause can happen early, that is, before the age of 40. Of the main consequences of early ovarian hormones deprivation or early menopause, one of the most alarming is the increased risk of cardiovascular diseases, contributing to an increase in the morbidity and mortality rate in these women. Our hypothesis is that early deprivation of ovarian hormones, when associated with the aging process, promotes more adverse cardiac remodeling and greater damage to cardiac function related to physiological ovarian failure. Thus, aerobic physical training is fundamental to attenuate these deleterious effects. PURPOSE: The objective of the present study was to investigate the effects of early deprivation of ovarian hormones on cardiac morphological and functional parameters in 82 week-old female rats subjected to ovariectomy at 10 weeks of age, as well as to evaluate the application of aerobic training as a non-pharmacological therapeutic tool. METHODS: Female Wistar rats (N = 48) were divided into two groups, at 10 weeks of life: early ovarian hormones deprivation by ovariectomy (OVX; N=24) and sham (SHAM; N=24).Between weeks 62 and 82, 12 animals of each group underwent aerobic training (OVX-T and SHAM-T, N=12). At the end of week 82, all were evaluated by echocardiography, cardiac function (Langendorff technique) and cardiac β-adrenergic receptor expression quantification. RESULTS: Echocardiography showed slight changes in morphology between OVX and SHAM. OVX (Δ= 101 ± 4.7 mmHg) showed higher values for maximal left intraventricular pressure in response to dobutamine, when compared to SHAM (Δ= 55 ± 11.8 mmHg).Both OVX-T (Δ= 70 ± 4.0 mmHg) and SHAM-T (Δ= 22 ± 6.6 mmHg) showed a reduction in this response. While, β-adrenergic receptor expression was not different between the sedentary groups, SHAM-T (0.23 ± 0.02AU) and OVX-T (0.29 ± 0.01AU) showed decreased expression of these receptors when compared to their respectively sedentary groups. CONCLUSIONS: Early ovarian hormones deprivation associated with aging, promotes discrete changes in cardiac morphology, increasing cardiac contractility. Aerobic training decreases β-adrenergic receptors expression, influencing the cardiac contractility. Supported by FAPESP Grant 01937-9