[The phenotypic change of smooth muscle cells in the media of pulmonary intra-acinar arteries during hypoxia].

The phenotypic change of smooth muscle cells (SMCs) in the media of pulmonary intraacinar arteries (IAA) was observed in rats during hypoxia. From 3 to 40 exposure days, pulmonary arterial pressure (PAP) and right ventricular hypertrophy increased parallely. From 1 to 5 exposure days, SMCs still displayed the "contractile" phenotype, but the amount of intercellular collagen slightly increased. After 7 exposure days, some medial SMCs changed into the "fully" or "partially" "synthetic" phenotype with an excess of intercellular collagen. From 14 to 40 exposure days, other than some SMCs of partially "synthetic" phenotype, a great number of SMCs acquired the "contractile" phenotype characteristics, but the synthetic and secretive organelles and intercellular collagen were still more than those in the groups from 1 to 5 exposure days. Our results suggested that along with the prolongation of hypoxic exposure, the kinetic changes of SMC phenotype might not parallel with PAP change.