title: The effect of in vitro tracheal occlusion on branching morphogenesis in fetal lung explants from the rat nitrofen model of congenital diaphragmatic hernia.
abstract: OBJECTIVE
  Fetal tracheal occlusion (TO) has been investigated as a treatment option for lung hypoplasia secondary to congenital diaphragmatic hernia. Tracheal occlusion has been shown to accelerate lung growth, but its effect on bronchial branching is unknown. In this study, we characterize the effects of in vitro TO on bronchial branch development in fetal lung explants derived from the nitrofen rat model of congenital diaphragmatic hernia.
  
  
  METHODS
  Rat dams were gavaged nitrofen on gestational day 9.5, and fetal lungs were harvested for explant culture on gestational day 14 (term, 22 days). Four experimental groups were investigated, with TO performed ex vivo using cautery: control, control + TO, nitrofen, and nitrofen + TO. Explants were incubated for 72 hours. Representative photographs were taken at 0, 24, 48, and 72 hours from the time of culture, and the number of distal branches was counted for each explant. The Student t test was used to compare distal branch measurements.
  
  
  RESULTS
  A minimum of 12 fetal lung explants were cultured for each group. By 24 hours, all explants undergoing TO had more branch iterations than explants that did not. Moreover, TO in nitrofen-exposed explants increased bronchial branching to control levels by 24 hours in culture.
  
  
  CONCLUSIONS
  Our results suggest that TO at day 14 increases branching in normal and nitrofen-exposed lung explants. In addition, TO increases airway branching in nitrofen-exposed explants to control levels suggesting that early TO reverses the lung hypoplasia seen in this model.
authors.affiliation: Division of Pediatric Surgery, The Montreal Children's Hospital, Montreal, Quebec, Canada.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Grushka
authors.forename: Saleh
authors.initials: S
authors.lastname: Al-Abbad
authors.forename: Robert
authors.initials: R
authors.lastname: Baird
authors.forename: Pramod
authors.initials: P
authors.lastname: Puligandla
authors.forename: Feige
authors.initials: F
authors.lastname: Kaplan
authors.forename: Jean-Martin
authors.initials: JM
authors.lastname: Laberge
mesh_terms: D000818:Animals; D001980:Bronchi / Q000196:embryology* / Q000473:pathology; D005315:Fetal Diseases / Q000473:pathology / Q000601:surgery*; D006548:Hernia, Diaphragmatic / Q000196:embryology* / Q000473:pathology / Q000601:surgery*; D065630:Hernias, Diaphragmatic, Congenital; D066298:In Vitro Techniques; D008168:Lung / Q000196:embryology / Q000473:pathology; D009024:Morphogenesis; D010647:Phenyl Ethers; D051381:Rats; D014132:Trachea / Q000601:surgery*
chemical_list: D010647:Phenyl Ethers; C007350:nitrofen