The effects of oligohydramnios and cervical cord transection on lung growth in experimental pulmonary hypoplasia in rabbits.
OBJECTIVE
Our goal was to examine the effects of oligohydramnios and cervical cord transection on fetal lung development, pulmonary surfactant, and lung mechanics in rabbits.


METHODS
The amniotic fluid was shunted into the maternal abdominal cavity in a group of 12 fetal rabbits. In another group (n = 12) high cervical cord transection was performed at day 24 of gestation. Another 12 littermates not operated on served as the control group. Fetuses were delivered on day 30 of gestation by cesarean section and immediately put to death. The body weight and wet lung and liver weights were measured. To determine the extent of fetal lung growth, we measured the size of lung acini, the number of terminal airspaces, and the diameter of alveoli. We also measured the dynamic compliance of the lung, the concentration of phosphatidylcholine, and the lecithin/sphingomyelin ratio in lung lavage fluid at birth.


RESULTS
Amniotic fluid shunting produced a significant reduction in amniotic fluid volume. Amniotic shunt and cervical cord transection significantly decreased wet lung weight and fetal lung/body weight ratio compared with the control. The concentration of phosphatidylcholine and the lecithin/sphingomyelin ratio in lung fluid lavage from fetuses with amniotic shunt were significantly higher than the values for control and cord transection fetuses. Histopathologic examination of the lungs showed significant reductions in the size of acini, the number of terminal airspaces, and the diameter of alveoli in shunted and cord transection groups compared with the control group. The dynamic compliance of transection fetuses was significantly reduced compared with control and shunted fetuses.


CONCLUSIONS
Our results indicate that oligohydramnios or cervical cord transections cause pulmonary hypoplasia. However, oligohydramnios-induced pulmonary hypoplasia is associated with increased pulmonary surfactant compared with control and cord transection fetuses.
Yoshimura
S
S
Department of Obstetrics and Gynecology, Nagasaki University School of Medicine, Sakamoto-machi, Japan.
Masuzaki
H
H
Miura
K
K
Hayashi
H
H
Gotoh
H
H
Ishimaru
T
T
D000818:Animals; D001835:Body Weight; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D005260:Female; D005324:Fetal Movement / Q000502:physiology; D005333:Fetus / Q000502:physiology; D037102:Lectins / Q000032:analysis; D008168:Lung / Q000196:embryology* / Q000254:growth & development* / Q000473:pathology; D008171:Lung Diseases / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D009929:Organ Size; D010713:Phosphatidylcholines / Q000032:analysis; D006831:Polyhydramnios / Q000150:complications* / Q000503:physiopathology; D011247:Pregnancy; D011650:Pulmonary Alveoli / Q000473:pathology / Q000503:physiopathology; D011663:Pulmonary Surfactants / Q000032:analysis; D011817:Rabbits; D012119:Respiration / Q000502:physiology*; D013109:Sphingomyelins / Q000032:analysis; D013116:Spinal Cord / Q000502:physiology / Q000601:surgery*
D037102:Lectins; D010713:Phosphatidylcholines; D011663:Pulmonary Surfactants; D013109:Sphingomyelins