Anne-Marie Koop

5 203 1. Housing and acclimatization 1.1.1. Use 20–30 g wild type C57 black 6 (C57BL/6) mice (institutional breeding line described previously 47 ), male and female, all more than 8 weeks old. House the mice in groups with a maximum of five per cage. In order to get used to human handling, let the mice acclimatize for at least 7 days. Do not perform any procedures during this period. 2. Pulmonary artery banding surgery 2.1. Preparation 2.1.1. Place the mouse in the induction chamber filled with 5% isoflurane/100% oxygen. Check for the lack of reflexes by giving a pain stimulus (i.e., toe pinch). 2.1.2. Shave the left hemithorax of the mouse using an electric shaver. 2.1.3. Gently pull out the tongue and hold with mild tension. 2.1.4. Illuminate the inner throat by placing a light source on the exterior throat at the level of the glottis. 2.1.5. Intubate the mouse endotracheally with a 20 G flexible cannula. 2.1.6. Place the animal on its right side on a heat mat (set temperature at 37 °C). 2.1.7. Connect the cannula to the miniventilator and start ventilation with 1.5%–2.5% isoflurane/oxygen (180 breaths/min, tidal 250 μL). 2.1.8. Inject 0.1 mg/kg buprenorphine subcutaneously for postoperative analgesia. 2.1.9. Prevent dehydration of the eye using eye ointment. 2.2. Pulmonary artery banding surgery by left lateral thoracotomy 2.2.1. Place the mouse on its right side by placing the right foreleg in a neutral position, the right hind leg extended, and the left foreleg bent back. 2.2.2. Disinfect the skin on the thorax with chloride-hexidine, swab two times. 2.2.3. Use sterile instruments for surgery. Open the skin with small scissors (round handle, 12 mm blades) from the left armpit parallel to the second and third rib. 2.2.4. Identify the m. pectoralis superficialis (oblique, superficial muscle) and the m. pectoralis profundus (oblique, underlying muscle). 2.2.5. Using suture loops, pull the m. pectoralis superficialis towards the ventral side and the m. pectoralis profundus towards the dorsal side of the mouse.