Figure 4.

Conversion of the male-dominant PH response to chronic hypoxia in wt mice to a female-dominant response in homozygous STAT5^−/− mice. Respective groups (n = 4–5) of approximately 8-wk-old mice of either gender and indicated genotype were exposed to hypobaric hypoxia for 7 wks or kept in room air. At the conclusion of the experiment, various parameters of PH were assessed (RVSP in A, RV/LV+S weight in B, medial wall thickness [as % outer diameter] in C, number of SMA-positive vessels per 10× field in D, and extent of tunica adventitia/perivascular collagen deposition as evaluated by Trichrome staining [blue] expressed in AUs in E). Data in each chart summarize mean ± SE. *P < 0.05 using multiple-group ANOVA and pair-wise t test.