Evaluation of the effect of estrogen on left ventricular remodeling in the rat model | ||
| Bulletin of Egyptian Society for Physiological Sciences | ||
| Article 18, Volume 26, Issue 2, December 2006, Pages 283-304 PDF (320.69 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/besps.2006.37577 | ||
| Authors | ||
| Lobna Kassem* ; Zeinab Alrefaie; Moshira Rateb | ||
| Department of Physiology, Kasr Al Aini Faculty of Medicine, Cairo University | ||
| Abstract | ||
| The aim of the present study was to investigate whether estrogen plays a role in remodeling of the left ventricle in the hearts of female rats. Four groups of animals were studied: control group, ovariectomized group, ovariectomized receiving estrogen treatment for 4 weeks and lastly ovariectomized animals receiving both estrogen and the protein kinase C inhibitor chelerythrene for 4 weeks. At the end of the four weeks period, the animals were sacrificed and left ventricular performance, left ventricular axis, left ventricular weight and heart weight were measured. The ventricular tissue level of metalloproteinase 9 (MMP-9) and the expression of collagen type I and angiotensin II type I receptors (AT1) were also assessed. Results of this work show that ovariectomy induced a reduction in left ventricular pressure, an increase in left ventricular axis, left ventricular weight and total heart weight as compared to sham operated group (P<0.05). The animals also showed an increased expression of collagen type I, AT1 receptors and increased level of MMP- 9 in ventricular tissue samples. Estrogen supplementation in ovariectomized animals improved the mechanical performance of the heart as evidenced by significant increase of left ventricular pressure, heart rate and dp/dt towards normal levels. It also reduces left ventricular hypertrophy and dilatation as significant reduction of left ventricular axis, left ventricular weight and heart weight towards control levels were observed. Furthermore, estrogen reduced the expression of collagen type I & AT1 receptors as well as the level of MMP-9 in ventricular tissues (P<0.05). Treatment of ovariectomized animals with both estrogen and the protein kinase C inhibitor chelerythrene (group IV) resulted in partial block of the cardioprotective effect of estrogen treatment alone (group III). We conclude that estrogen, possibly through a mechanism that involves protein C activation, seems to reduce left ventricular hypertrophy and dilatation as well as left ventricular tissue level of MMP- 9 and expression of collagen type I & AT1 receptors while maintaining left ventricular pressure and performance. Such results suggest a positive role of estrogen in cardiac protection in female rats through regulating certain Key elements involved in the process of ventricular remodeling. | ||
| Keywords | ||
| Estrogen; left ventricle remodeling; angiotensin II receptors; metalloproteinases; collagen; protein kinase C | ||
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