After set duration of hypoxic or normoxic exposure, mice were weighed and anesthetized with Avertin (tribromoethanol) 0.375 mg/g body weight injected intraperitoneally. A tracheostomy was performed with a 22 gauge angiocatheter and secured in place with a 4.0 silk suture. Mice were ventilated with a Harvard Mini-Vent with a stroke volume of 325 µl and rate of 150 stroke/min. Anesthesia was maintained throughout with 1% isoflurane mixed with room air or 10% O2. After thoracotomy, a 25 gauge needle fitted to a pressure transducer was inserted into the right ventricle. Right ventricular systolic pressure (RVSP) was measured and continuously recorded on a Gould polygraph (model TA-400, Gould instruments, Cleveland, Ohio). Immediately after RVSP measurements were obtained, the mice were sacrificed.
An expanded Materials and Methods section is available in the online data supplement at http://circres.ahajournals.org and provides details of all materials, bone marrow transplantation, pulmonary vascular morphometry, Western blot, immunohistochemistry, immunofluorescence and statistical analyses.