Female Adult Mouse Cardiomyocytes Are Protected Against Oxidative Stress

Abstract

Premenopausal women have less cardiovascular disease and lower cardiovascular morbidity and mortality than men the same age. Our previous studies showed that female mice have lower mortality and better preserved cardiac function after myocardial infarction. However, the precise cellular and molecular mechanisms responsible for such a sex difference are not well established. Using cultured adult mouse cardiomyocytes (ACMs), we tested the hypothesis that the survival advantage of females stems from activated estrogen receptors (ER) and Akt survival signaling pathways. ACMs were isolated from male and female C57BL/6J mice and treated with hydrogen peroxide (H 2 O 2 , 100 μM) for 30 min. Cell survival was indicated by rod ratio (rod shaped cells/total cells) and cell death by lactate dehydrogenase (LDH) release and positive staining of Annexin-V (AV + , a marker for apoptosis) and propidium iodide (PI + , a marker for necrosis). In response to H 2 O 2, female ACMs exhibited a higher rod ratio, lower LDH release and fewer AV + and PI + cells compared to males. Phospho-Akt was greater in females both at baseline and after H 2 O 2 stimulation. The downstream molecule of Akt, phosphor-GSK-3β (inactivation), was also higher while caspase-3 activity was lower in females in response to H 2 O 2 . Bcl-2 did not differ between genders. ERα was the dominant isoform in females, whereas ERβ was low but similar in both genders. Our findings demonstrate that female ACMs have a greater survival advantage when challenged with oxidative stress-induced cell death. This may be attributable to activation of Akt and inhibition of GSK-3β and caspase-3 through an ERα-mediated mechanism.

Salidroside Protects Against Hydrogen Peroxide-Induced Injury in Cardiac H9c2 Cells via PI3K-Akt Dependent Pathway

“…H 2 O 2 stimulation induced lipid peroxidation; MDA increased significantly. Wang et al (2010) reported that 100 mM H 2 O 2 induced necrosis and apoptosis in adult mouse cardiomyocytes; similarly, we exposed H9c2 cells to 150 mM H 2 O 2 and observed that the marker of cell necrosis, LDH activity in supernatant, increased remarkably; in addition, cell apoptosis evaluated by Hoechst 33258, late apoptosis, and secondary necrosis detected by flow cytometry were also increased. These results indicated that H 2 O 2 stimulation was accurately mimicking the pathogenesis of oxidative stress by increase in H 2 O 2 concentration, lipid peroxidation level, cell necrosis, and apoptosis.…”

Estrogen attenuates coupling factor 6-induced salt-sensitive hypertension and cardiac systolic dysfunction in mice

“…8,32,36 Estrogen increases protein S-nitrosylation, a common posttranslational protein modification, 37 and reduces inflammatory markers 32,38 and afterload-or agonist-induced cardiac hypertrophy via the inhibition of calcineurin hypertrophic transcription factor and mitogen-activated protein kinase signaling pathways. 39 Estrogen also improves endothelial and myocardial function after ischemia by an antiapoptotic and pro-survival effect on cardiomyocytes, 40,41 endothelial progenitor cell mobilization 42 and mesenchymal stem cell-mediated vascular endothelial growth factor release. 43,44 These rapid effects of estrogen on the action of CF6 were not examined in this study.…”

Estrogen receptor α gene PvuII polymorphism and coronary artery disease: a meta-analysis of 21 studies

“…It has been suggested that the cardiovascular functions of estrogen depend on estrogen receptors α (ERα) and β (ERβ) encoded by separate genes, ESR1 and ESR2, respectively (Mendelsohn and Karas, 2005). ERα plays a more important role than ERβ in cardioprotection, and is involved in vasodilation (Figtree et al, 2003), attenuation of cardiac cell apoptosis (Wang et al, 2010;Liu et al, 2011), and stimulation of neovascularization (Hamada et al, 2006;Jesmin et al, 2010).…”