Search

Aortic valve regurgitation (AR) can result in heart failure from chronic overloading of the left ventricle (LV). Little is known of the role of estrogens in the LV responses to this condition. The aim of the study was to compare LV remodeling in female rats with severe AR in absence of estrogens by ovariectomy (Ovx). In a first study, we investigated over 6 months the development of hypertrophy in four groups of female Wistar rats: AR or sham-operated (sham) and Ovx or not. Ovx reduced normal heart growth. As expected, volume overload (VO) from AR resulted in significant LV dilation (42% and 32% increase LV end-diastolic diameter in intact and Ovx groups vs. their respective sham group; p Nppa) gene expression was reduced by Ovx in sham-operated females whereas brain natriuretic peptide (Nppb) expression was increased. Alpha (Myh6) and beta (Myh7) myosin heavy chain genes were also significantly modulated by Ovx in sham females. In AR rats, LV expression of both Nppa and Nppb genes were increased as expected. Ovx further increased it of AR rats for Nppa and did the opposite for Nppb. Interestingly, AR in Ovx rats had only minimal effects on Myh6 and Myh7 genes whereas they were modulated as expected for intact AR animals. In summary, loss of estrogens by Ovx in AR rats was not accompanied by a worsening of hypertrophy or cardiac function. Normal cardiac growth was reduced by Ovx in sham females but not the hypertrophic response to AR. On the other hand, Ovx had important effects on LV gene expression both in sham and AR female rats.