title: [Pulmonary vascular remodeling in neonatal rats with hypoxic pulmonary hypertension].
abstract: OBJECTIVE
  To study the changes of pulmonary vascular remodeling in the pathogenesis of hypoxia-induced pulmonary hypertension (HPH) in neonatal rats.
  
  
  METHODS
  Ninety-six newborn Wistar rats were randomly divided into an HPH group (hypoxia exposure) and a control group (room air exposure). The mean pulmonary arteria pressure (mPAP), right ventricle hypertrophy index (RVHI), and vascular remodeling indexes MT% and MA% were measured 3, 5, 7, 10, 14 and 21 days after exposure (n=8 each time point). The ultrastructure of pulmonary vascular was observed under a transmission electron microscope.
  
  
  RESULTS
  mPAP in the HPH group 3, 5, 7, 10, 14 and 21 days after hypoxia exposure increased compared with the control group (P<0.05). With the prolonged hypoxia time, mPAP in the HPH group increased more significantly. MT%, MA% and RVHI increased significantly in the HPH group after 7 days of hypoxia exposure in a time-dependent manner compared with the control group (P<0.05). The transmission electron microscopy demonstrated that small pulmonary arterials became thickened, endothelial cell hyperplasia and degeneration, and organelles increased in the HPH group after 7 days of hypoxia exposure. Besides, collagen deposition in the extracellular matrix and the changes of pulmonary vascular remodeling were observed.
  
  
  CONCLUSIONS
  mPAP increases between 3 and 5 days of hypoxia exposure, resulting from pulmonary vascular spasm caused by hypoxia. After hypoxia of 7 days, the mPAP increases more significantly, pulmonary vascular remodeling occurs, and right ventricle becomes irreversibly hypertrophic. These changes may be intensified as the prolonged hypoxia time.
authors.affiliation: Department of Neonatology, First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Sang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ming-Xia
authors.initials: MX
authors.lastname: Li
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure; D016232:Endothelins / Q000502:physiology; D006976:Hypertension, Pulmonary / Q000209:etiology*; D017380:Hypertrophy, Right Ventricular / Q000209:etiology; D000860:Hypoxia / Q000150:complications; D011651:Pulmonary Artery / Q000473:pathology* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016232:Endothelins