Atrial Naturitic Peptide, Heat Shock Protein 70 and c-FOS Modulate Estrogen Protective Effect on Cardiac Performance in Female Rats Subjected to Immobilization Stress
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- Category: Vol. 78, March 2010
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Atrial Naturitic Peptide, Heat Shock Protein 70 and c-FOS Modulate Estrogen Protective Effect on Cardiac Performance in Female Rats Subjected to Immobilization Stress, HEMMAT M. KHLOUSSY, MOSHIRA A. RATEB, AHMAD D. BADAWY and ABDULLAH R. EL-SWERKY
Abstract
Several international clinical trials have reported contro-versial effects of estrogen replacement therapy on the cardio-vascular system. The aim of this study was to investigate the effects of estrogen on myocardial performance under conditions of simulated emotional stress in female rats and to elucidate some of its intracellular mediators in the myocardium.
Material and Methods: 64 female albino rats were included in this study and classified into four main groups; each group included 16 rats.
Group 1 (Control group), group 2 immobilization stress group (IMO), group 3 (IMO + ovariectomy), group 4 (IMO+ Ovariectomy + estrogen supplementation 10mg/100gm, once daily by intramuscular injection for 2 weeks). At the end of the experimental protocol, evaluation of cardiac performance in isolated hearts and measurement of cardiac tissue gene expression of c-FOS, HSP 70 and ANP m-RNAs was conducted.
Results: Immobilization stress (IMO) group showed significant increase in systolic blood pressure (SBP) and diastolic blood pressure (DBP). The animals also showed a significant increase in gene expression of c-FOS (functional marker of cellular activation) and heat shock protein (cardio-protective substance, HSP70) and significant decrease in contractility index in comparison to control group.
Ovariectomized immobilized group (OVE + IMO group 3) showed significant increase in SBP, DBP, c-FOS expression and significant decrease in atrial naturetic peptide (ANP) and HSP70 expression in comparison to IMO group.
Administration of estrogen to OVE rats followed by immobilization stress caused a significant decrease in SBP, DBP, c-FOS expression and a significant increase in ANP and HSP70 expression in comparison to IMO + OVE group.
Conclusion: Estrogen up-regulation of expression of ANP and HSP 70 and down-regulation of c-FOS in the myo-cardium can confer a protective effect on myocardial perfor-mance in states of immobilization stress.