Studies On The Role Of Structural Changes Of Pulmonary Arterial Smooth Muscle Cells In The Development Of Hypoxic Pulmonary Hypertension And Its Mechanism

The characteristics, effect, and mechanism of structural changes of pulmonary arterial smooth muscle cells ( PASMC ) during hypoxic pulmonary hypertension ( HPH ) were systematically studied at various levels of intact animal, tissue, cell, and molecule. The main results were as follows.1. The effect of structural changes of PASMC on the development of HPH:(1) Only after 24 hours of exposure to hypoxia, the muscularization of pulmonary intra-acinar arteries ( IAA ) of rats took place and deteriorated with the prolongation of the exposure, resulting in extension of resistent vascular segments and increment of pulmonary arterial pressure ( PAP ). There is no doubt that the development of HPH was based on the structural changes of the vessels mentioned above.(2) The dynamic changes of PASMC phenotype in vivo during chronic hypoxia were firstly found, i.e., along with the prolongation of hypoxic exposure ( from 1 to 40 days ), some PASMC in media could change their contractile phenotype, through partially synthetic pbenotype, into synthetic phenotype, and then return to contractile phenotype. Similarity, the hydrozyproline ( main constructive amino acid of collagen ) content of pulmonary arterial wall continuely increased at first, and then tended to decrease. These indicated the possibility of retrieval of structural remodeling, showing a good prospect for the prevention and treatment of HPH. On the other hand,it was suggested that the dynamic change of PASMC phenotype might take part in adjustment to HPH.