title: A hyperoxic lung injury model in premature rabbits: the influence of different gestational ages and oxygen concentrations.
abstract: BACKGROUND
  Many animal models have been developed to study bronchopulmonary dysplasia (BPD). The preterm rabbit is a low-cost, easy-to-handle model, but it has a high mortality rate in response to the high oxygen concentrations used to induce lung injury. The aim of this study was to compare the mortality rates of two models of hyperoxia-induced lung injury in preterm rabbits.
  
  
  METHODS
  Pregnant New Zealand white rabbits were subjected to caesarean section on gestational day 28 or 29 (full term  = 31 days). The premature rabbits in the 28-day gestation group were exposed to room air or FiO₂ ≥95%, and the rabbits in the 29-day gestation group were exposed to room air or FiO₂  = 80% for 11 days. The mean linear intercept (Lm), internal surface area (ISA), number of alveoli, septal thickness and proportion of elastic and collagen fibers were quantified.
  
  
  RESULTS
  The survival rates in the 29-day groups were improved compared with the 28-day groups. Hyperoxia impaired the normal development of the lung, as demonstrated by an increase in the Lm, the septal thickness and the proportion of elastic fibers. Hyperoxia also decreased the ISA, the number of alveoli and the proportion of collagen fibers in the 28-day oxygen-exposed group compared with the control 28-day group. A reduced number of alveoli was found in the 29-day oxygen exposed animals compared with the control 29-day group.
  
  
  CONCLUSIONS
  The 29-day preterm rabbits had a reduced mortality rate compared with the 28-day preterm rabbits and maintained a reduction in the alveoli number, which is comparable to BPD in humans.
authors.affiliation: Integrated College of Bauru, Bauru, São Paulo, Brazil.
authors.forename: Roberta Munhoz
authors.initials: RM
authors.lastname: Manzano
authors.affiliation: Pro Matre Paulista Hospital, São Paulo, São Paulo, Brazil.
authors.forename: Renata Suman
authors.initials: RS
authors.lastname: Mascaretti
authors.affiliation: Albert Einstein Jewish Hospital, São Paulo, São Paulo, Brazil.
authors.forename: Valéria
authors.initials: V
authors.lastname: Carrer
authors.affiliation: Albert Einstein Jewish Hospital, São Paulo, São Paulo, Brazil.
authors.forename: Luciana Branco
authors.initials: LB
authors.lastname: Haddad
authors.affiliation: Albert Einstein Jewish Hospital, São Paulo, São Paulo, Brazil.
authors.forename: Aline Rabelo
authors.initials: AR
authors.lastname: Fernandes
authors.affiliation: Saint Isabel Hospital, Aracajú, Sergipe, Brazil.
authors.forename: Ana M A
authors.initials: AM
authors.lastname: Reyes
authors.affiliation: Albert Einstein Jewish Hospital, São Paulo, São Paulo, Brazil; School of Medicine - Clinics Hospital University of Sao Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Celso Moura
authors.initials: CM
authors.lastname: Rebello
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001997:Bronchopulmonary Dysplasia / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D005865:Gestational Age; D006801:Humans; D018496:Hyperoxia / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D053208:Kaplan-Meier Estimate; D010100:Oxygen / Q000378:metabolism*; D011247:Pregnancy; D011650:Pulmonary Alveoli / Q000378:metabolism / Q000473:pathology; D011817:Rabbits
chemical_list: D003094:Collagen; D010100:Oxygen
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