Postnatal lung mechanics, lung composition, and surfactant synthesis after tracheal occlusion vs prenatal intrapulmonary instillation of perfluorocarbon in fetal rabbits.
OBJECTIVE
Fetal tracheal occlusion (TO) accelerates lung growth but decreases surfactant production. We have previously shown that instillation of perfluorooctylbromide (PFOB) into fetal rabbit lungs leads to lung growth similar to TO. This study compares neonatal lung mechanics and surfactant production after prenatal intrapulmonary PFOB instillation vs TO.


METHODS
In each of 18 pregnant rabbits on gestational day 27, sets of 4 fetuses underwent either (1) intrapulmonary instillation of 1 mL PFOB, (2) TO, (3) instillation of 1 mL 0.9% NaCl (saline), and (4) hysteroamniotomy without fetal manipulation (control). Fetuses were born by cesarean delivery after 48 hours. Fetuses of 12 rabbits were mechanically ventilated for 15 minutes to evaluate lung compliance and airway resistance. Pulmonary surfactant protein B (SP-B) was quantified by immunohistochemistry in fetuses of the remaining 6 rabbits.


RESULTS
Compliance was decreased in the TO group after cesarean delivery (0.33 +/- 0.13 mL/cm H2O) compared with PFOB (0.59 +/- 0.12 mL/cm H2O), saline (0.50 +/- 0.12 mL/cm H2O), and control (0.52 +/- 0.10 mL/cm H2O) fetuses. Mean fetal lung to body weight ratio was higher in TO and PFOB fetuses compared with saline and control. Higher water content and lower numbers of surfactant protein B-positive cells were found in the TO-treated fetuses.


CONCLUSIONS
Both prenatal intrapulmonary instillation of PFOB and TO accelerate lung growth, but TO is associated with decreased postnatal lung compliance, possibly influenced by decreased surfactant production and increased fluid retention. Conversely, instillation of PFOB preserved lung compliance and surfactant synthesis.
Muensterer
Oliver J
OJ
Department of Pediatric Surgery, Dr. von Hauner Children's Hospital, University of Munich, 80337 Munich, Germany. oliver.muensterer@ccc.uab.edu
Flemmer
Andreas W
AW
Bergmann
Florian
F
Hajek
Kerstin S
KS
Lu
Hui Qi
HQ
Simbruner
Georg
G
Deprest
Jan A
JA
Till
Holger
H
D000280:Administration, Inhalation; D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001823:Body Composition; D005260:Female; D005325:Fetal Organ Maturity / Q000187:drug effects; D005466:Fluorocarbons / Q000008:administration & dosage*; D006842:Hydrocarbons, Brominated; D008026:Ligation; D008168:Lung / Q000187:drug effects / Q000196:embryology*; D008170:Lung Compliance / Q000187:drug effects; D023421:Models, Animal; D009929:Organ Size / Q000187:drug effects; D011247:Pregnancy; D037701:Pulmonary Surfactant-Associated Protein B / Q000096:biosynthesis*; D011817:Rabbits; D012121:Respiration, Artificial; D015656:Respiratory Mechanics / Q000187:drug effects; D019141:Respiratory System Agents / Q000008:administration & dosage*; D014132:Trachea / Q000601:surgery*
D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; D037701:Pulmonary Surfactant-Associated Protein B; D019141:Respiratory System Agents; C003072:perflubron