title: Increased contractility and impaired relaxation of the left pulmonary artery in a rabbit model of congenital diaphragmatic hernia.
abstract: OBJECTIVE
  Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypertension which is often difficult to manage and a significant cause of morbidity and mortality. Our aim was to study the pulmonary artery reactivity in an animal model of CDH.
  
  
  METHODS
  To investigate the reactivity of the aorta and left pulmonary artery in a rabbit model of CDH, we studied the in vitro responses to the α1-adrenoceptor agonist phenylephrine (PE) and to both the muscarinic receptor agonist (ACh) and the nitric oxide (NO) donor sodium nitroprusside (SNP). Rabbits underwent surgery at 25 days of gestation. CDH was created in one fetus per horn (n = 8). Remaining fetuses were considered controls (n = 18). At term (30 days), the lung, left pulmonary artery, and aorta were dissected. In a separate group, endothelium was mechanically removed.
  
  
  RESULTS
  There were no differences in the contractile and relaxing responses of aorta in all groups. In left pulmonary artery, PE-induced contractions were significantly greater (p < 0.05) in CDH when compared with control group. The increased responsiveness to PE in CDH group was similar to that found in pulmonary artery without endothelium. The ACh-induced pulmonary artery relaxation was markedly reduced in CDH when compared with control group (p < 0.05), whereas no differences were found for SNP.
  
  
  CONCLUSIONS
  Our results show increased contractility and impairment in endothelium-dependent relaxation of pulmonary artery in CDH, mimicking an endothelial dysfunction, with preserved response to endothelium-independent mechanism.
authors.affiliation: Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Augusto Frederico
authors.initials: AF
authors.lastname: Schmidt
authors.forename: Julio Alejandro
authors.initials: JA
authors.lastname: Rojas-Moscoso
authors.forename: Frances Lilian Lanhellas
authors.initials: FL
authors.lastname: Gonçalves
authors.forename: Rodrigo Melo
authors.initials: RM
authors.lastname: Gallindo
authors.forename: Fabíola Zakia
authors.initials: FZ
authors.lastname: Mónica
authors.forename: Edson
authors.initials: E
authors.lastname: Antunes
authors.forename: Rebeca Lopes
authors.initials: RL
authors.lastname: Figueira
authors.forename: Lourenço
authors.initials: L
authors.lastname: Sbragia
mesh_terms: D000818:Animals; D001835:Body Weight; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000502:physiology*; D006548:Hernia, Diaphragmatic / Q000473:pathology / Q000503:physiopathology; D065630:Hernias, Diaphragmatic, Congenital; D066298:In Vitro Techniques; D008168:Lung / Q000473:pathology; D009929:Organ Size; D011651:Pulmonary Artery / Q000503:physiopathology*; D011817:Rabbits; D014661:Vasoconstriction / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*