Early ovarian hormone deprivation increases cardiac contractility in old female rats-Role of physical training.

OBJECTIVES

We investigated the effects of early ovarian hormones deprivation on morphology and cardiac function and the effects of aerobic training on these parameters, in old rats.

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 groups. OVX group (Δ = 101 ± 4.7 mmHg) showed higher values for maximal left intraventricular pressure in response to dobutamine, when compared to SHAM group (Δ = 55 ± 11.8 mmHg). Both OVX-T (Δ = 70 ± 4.0 mmHg) and SHAM-T (Δ = 22 ± 6.6 mmHg) groups showed a reduction in this response. While, β-adrenergic receptor expression was not different between the untrained groups, SHAM-T (0.23 ± 0.02 AU) and OVX-T (0.29 ± 0.01 AU), showed decreased expression of these receptors.

CONCLUSION

Early ovarian hormones deprivation associated with aging, promotes discrete changes in cardiac morphology and increasing cardiac contractility. Aerobic training decreases β-adrenergic receptors expression, influencing the cardiac contractility.