Fig. 4.

Mice administered SU5416 (20 mg/kg sc) once a week for 3 consecutive wk and exposed to nitrogen dilution hypoxia for 3 wk (n = 5) are compared with mice exposed only to chronic hypoxia (n = 5). Neither right ventricular hypertrophy nor RVSP were different when the 2 groups were compared (A and B); there was no difference in the hematocrit (C). Lung histology (HE staining) shows some degree of air space enlargement (D–F). Rare small vessel thrombi were observed (G). As evidenced by trichrome staining, RV fibrosis was absent (H).