Experimental studies showed that 17β-estradiol (E2) and activated Estrogen Receptors (ER)
April 15, 2017
Experimental studies showed that 17β-estradiol (E2) and activated Estrogen Receptors (ER) protect the heart from ischemic injury. role of activation of ERα in cardiomyocytes which is not feasible in a loss of function approach. This study helps to elucidate the protective potential of ERα in cardiomyocytes under ischemic conditions. Targeted activation of ERα to enhance cardioprotective mechanisms could provide novel therapeutic options for the diseased hearts. Materials and Methods Transgenic animals Inducible double transgenic mice with cardiomyocyte-specific ERα overexpression (ERα-OE) were generated through mating of monotransgenic ERα (tetO-mERα) and monotransgenic α-MHC-tTA mice using Tet-Off system (for more details see Material and Methods in the supplementary material). Since cardiac phenotype and function of monotransgenic tetO-mERα and α-MHC-tTA mice did not significantly differ from wild type-littermates (WT data not shown) we did not include the monotransgenic mice in further analysis and only the WT-littermates were used as control. All animal experiments were approved by and conducted in accordance with the guidelines set out by the State AZD2281 Agency for Health and Social Affairs (LaGeSo Berlin Germany G 0360/08) and conform to the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of health (NIH Publication No. 85-23 revised AZD2281 1996). Myocardial infarction model MI was induced in Female (F) and Male (M) mice at 12 weeks of AZD2281 age by permanent left anterior descending Coronary Artery (LAD) ligation. Mice were anesthetized with ketamine hydrochloride (80 mg/ml)/xylazine hydrochloride (12 mg/ml) solution administered by intraperitoneal injection at a dose of 1 1 mg/kg. Briefly after intubation LAD coronary artery was ligated with a 7.0 polypropylene suture. As FGD4 non-infarcted controls mice underwent a sham operation where the ligature around the LAD was not tied. Animals were recovered from anaesthesia under warming conditions and normal ventilation. The animals were treated with rimadyl (5 mg/kg) for analgesia up to 7 days post-surgery. Two weeks after MI animals were sacrificed and hearts were harvested for further analysis. To evaluate cardiac function and morphology echocardiography was performed before thoracotomy and 14 days after MI in sedated mice with the echocardiography system (Vevo 770 High-Resolution Imaging System Toronto Canada) equipped with a 20-55 MHz transducer. Infarct size was determined as described else  somewhere. Quickly two-dimensional cineloops through the parasternal lengthy axis view had been obtained using the EKV?-setting (ECG-Gated Kilohertz Visualization) that allows the evaluation of cardiac wall structure motion with the best temporal resolution obtainable in little pet imaging today (≡1000 fps). For MI size dedication the entire cardiac routine was shown in slow movement to be able to obviously identify infarcted areas that have been thinned and akinetic. The inner boundary from AZD2281 the infarcted area (MI boundary) as well as the endocardial boundary of the complete LV (LV boundary) were tracked at end-diastole. MI size (in %) was determined as: MI boundary × 100/LV boundary. Isolation of adult mouse ventricular cardiomyocytes and cell tradition Ventricular cardiomyocytes had been isolated from 2-3 month older feminine and male WT- and ERα-OE mice by a typical enzymatic technique as referred to before . Quickly animals had been anesthetized with isoflurane accompanied by intraperitoneal shot of 8 μg xylazine and 35 μg ketamine. Hearts had been rapidly eliminated and perfused with a minimal Ca2+ collagenease bicarbonate buffer remedy (36°C pH 7.4) for 10 min. Consequently the ventricles had been minced. After many wash measures isolated cardiomyocytes had been finally resuspended in M199 moderate (Sigma Germany) supplemented with 0.2% bovine serum albumin 5 fetal leg serum 5 mmol/l creatine 5 mmol/l taurine 2 mmol/l carnitine 10 μmol/l cytosine-D-arabinofuranoside and antibiotics. Cardiomyocytes had been seeded along with 0.2% laminin-coated 4-well chamber slides (Nunc Wiesbaden-Schierstein Germany) and cultured for 4 h in M199 medium before measurement of their length. Cell morphology The average person width and amount of the cardiomyocytes were determined on micrographs captured.