Sildenafil inhibits hypoxia-induced nuclear translocation of NFATc3 in cultured human PASMC. Human PASMC were cultured with SMBM (2% FBS) under nomoxia or hypoxia (3% O2) in the presence of sildenafil (100 nM), 8-brom-cGMP (100 μM), SKF96365 (7.5 μM) or VIVIT (4 μM) respectively for 72 h. NFATc3 was determined by confocal microscopy of immunofluorescence. The primary antibody of NFATc3 was detected with Rhodamine (TRITC)-conjugated AffiniPure Goat Anti-mouse IgG (green). Slides were counterstained with nuclei dye hoechest33258 (blue). A: Immunofluorescence image of NFATc3 in human PASMC (×1000). B: The nuclear translocation of NFATc3 was calculated by comparing the ratio of nuclear NFATc3 immunofluorescence/total NFATc3 immunofluorescence. n = 20, ### P < 0.001 vs. normoxia, *** P < 0.001 vs. hypoxia.