Influence of maternal pneumonectomy on fetal lung growth.

This study was conducted to test the hypothesis that the compensatory growth of the maternal lung during pregnancy influences fetal lung growth, specifically the fetal lung DNA content. A left pneumonectomy (PN) was performed in pregnant albino rats at different gestation days (GD 3, 7, 9, 10, 12, 14, 16 and 18) and the rats sacrificed at GD 21. Only mothers with litter size of 9-14 fetuses were used for this study. Maternal lung growth was assessed by measuring lung weight, lung air volume and lung DNA content, and the fetal lung growth by lung DNA content. The findings were: (1) pregnancy did not influence the rate of compensatory growth of the remaining lung following PN; (2) neither thoracotomy nor PN had any effect on placental weight or DNA content; (3) lung DNA content for body weight was larger in fetuses of PN rats when PN was performed in the first half of gestation; (4) there was a direct relationship between DNA content of the fetal lung and maternal lung in PN rats; and (5) neither thoracotomy nor PN in pregnant rats influenced the maturation of the fetal lung. The results suggest that a growth factor(s), specific for lungs, is released into maternal circulation following PN, crosses the placenta and enhances the fetal lung growth without affecting its maturation.