TAC Mouse Model and Echocardiography

This study was approved by the Animal Ethical Experimentation Committee (DEC. 2013.II.02.019, Utrecht University) and was carried out under the Guide for the Care and Use of Laboratory Animals. Transverse aorta constriction was performed as previously described (17). In brief, 12 weeks old miR-132/212 KO mice or their WT control litters were subjected to TAC or sham surgery. Surgical procedures were performed under sterile conditions with breathing pump and mice were anesthetized with fentanyl (0.05 mg/kg), midazolam (5 mg/kg), and medetomidine (0.5 mg/kg) by intraperitoneal injection. After exposing the transverse aorta, a 27 gauge constriction was made between the first and second branches of the aortic as previously described. After closure, mice recovered upon atipamezole (2.5 mg/kg) and flumazenil (0.5 mg/kg). After surgery, Temgesic (0.1 mg/kg) was given as a painkiller every 8 h for 2 days. Sham surgery was conduction in the same way without gauge constriction. Echocardiography and cardiac function testing were performed both before and 7 weeks following TAC with the Vevo® 2100 System (Visualsonics) and analyzed with Vevo2100-1.6.0 (Visualsonics) software as previously described. During the measurement, mice were under anesthesia with isoflurane and their body temperature was maintained at 37°C. Two mice dropout 1 day after surgery where were excluded later analysis. To terminate the mice, mice were anesthetized overdose anesthesia with fentanyl (0.1 mg/kg), midazolam (10 mg/kg), and medetomidine (1 mg/kg) by intraperitoneal injection.