Abstract
Background: Intrauterine growth restriction (IUGR) is associated with asthma in childhood and adulthood. Abnormalities in airway and lung structure accompanying IUGR may predispose children to the development of asthma.
Aim: To determine the structural consequences in the lungs of adult offspring born from IUGR pregnancies using a maternal hypoxia-induced IUGR rat model.
Methods: Pregnant Sprague Dawley rats were housed under hypoxic conditions (11.5% O2) from gestational days E13-E20 and then returned to normoxia (21% O2). A control group of pregnant rats was housed under normoxic conditions throughout pregnancy. Weights of male offspring at birth and 7 weeks of age were recorded at which point bronchoalveolar lavage fluid (BALf) was collected for total cell counts and lungs fixed for morphometry/stereology.
Results: Offspring born to dams exposed to hypoxic conditions were lighter at birth compared with Control (P<0.01), but not at 7 weeks (P=0.49). There was increased total cells in BALf of the IUGR offspring (P<0.01), which were predominantly macrophages. There were no differences in mean thickness of the epithelium, airway smooth muscle layer, inner wall, outer wall or total wall between groups at 7 weeks. However, there was greater anatomical variation in airway lumen area in the IUGR group (P<0.05). There was no difference in the surface area of alveoli, lung volume or parenchymal volume.
Conclusion: In utero growth restriction resulted in a more heterogeneous distribution of airway lumen calibre with potential implications for ventilation. The increased number of lung macrophages in adulthood indicates a phenotypic change that has a fetal origin and warrants further investigation.
- Copyright ©the authors 2016