Figure 2

Proliferative activity and muscularization of intrapulmonary vessels of untreated mice and of animals injected with 0.2% carboxymethylcellulose as vehicle or with rapamycin. Mice were kept for four days (A) or three weeks (B) at normoxia or at hypobaric hypoxia. In frozen lung sections stained with anti-Ki67 and anti α-smooth muscle actin the number of proliferating cells per cross section of a vessel was quantified (A). The extent of muscularization of intrapulmonary arteries was quantified by computer-aided planimetry (B). The results are given as boxplots (N: normoxia; H: hypobaric hypoxia; CMC: carboxymethylcellulose; Rapa: rapamycin; n = number of animals).