Figure 4.

Hypoxia-inducible factor-1α (HIF-1α) shRNA suppresses the hypoxia-induced acceleration of proliferation and cell cycle of pulmonary artery smooth muscle cells (PASMCs). PASMCs were infected with lentiviruses harboring HIF-1α shRNA #1 or scramble shRNA, and exposed to hypoxia (5% O₂) for 48 h. (A) The number of viable cells was determined by MTT assay. (B and C) The cells were fixed and stained with PI, and cell cycle was analyzed by flow cytometry. (B) Statistical analysis of 3 independent experiments, and (C) a set of representative flow cytometry results. The values are expressed as the means ± SD of triplicate experiments. ^***P<0.001, hypoxia vs. normoxia; ^##P<0.01 and ^###P<0.001, hypoxia + HIF-1α shRNA vs. hypoxia.