Document Detail

Effect of increased lung expansion on lung growth and development near midgestation in fetal sheep.
MedLine Citation:
PMID:  10832742     Owner:  NLM     Status:  MEDLINE    
Obstruction of the fetal trachea is a potent stimulus for fetal lung growth and may have therapeutic potential in human fetuses with lung hypoplasia. However, the effects of increased lung expansion on lung development near midgestation, which is the preferred timing for fetal intervention, have not been well studied. Our aim was to determine the effects of increased lung expansion on lung development at 75-90 d of gestation in fetal sheep. In three groups of fetuses (n = 4 for each), the trachea was occluded for either 10 [10-d tracheal occlusion (TO) group] or 15 d (15-d TO group) or left intact (control fetuses). TO for both 10 and 15 d caused fetal hydrops, resulting in significantly increased fetal body weights. Both periods of TO significantly increased total lung DNA contents from 99.8 +/- 10.1 to 246.0 +/- 5.3 and 246.9 +/- 48.7 mg in 10- and 15-d TO fetuses, respectively. TO for 10 and 15 d also increased airspace diameter, although the percentage of lung occupied by airspace was not increased in 10-d TO fetuses due to large increases in interairway distances; this resulted from a large increase in mesenchymal tissue. The interairway distances at 15 d of TO were reduced compared with the 10-d value but were still approximately 30% larger than control values. We conclude that TO at <90 d of gestation in fetal sheep induces a greater increase in lung tissue growth than later in gestation but also causes fetal hydrops and produces changes in lung structure that are not compatible with efficient gas exchange. Thus, increased lung expansion at a similar stage of development in human fetuses is unlikely to induce changes in lung development that would facilitate gas exchange after birth.
M E Probyn; M J Wallace; S B Hooper
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pediatric research     Volume:  47     ISSN:  0031-3998     ISO Abbreviation:  Pediatr. Res.     Publication Date:  2000 Jun 
Date Detail:
Created Date:  2000-09-07     Completed Date:  2000-09-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0100714     Medline TA:  Pediatr Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  806-12     Citation Subset:  IM    
Department of Physiology, Monash University, Clayton, Victoria, Australia.
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MeSH Terms
Body Weight
Carbon Dioxide / blood
DNA / metabolism
Embryonic and Fetal Development
Lung / anatomy & histology,  embryology*,  metabolism
Organ Size
Oxygen / blood
Proteins / metabolism
Sheep / embryology*
Reg. No./Substance:
0/Proteins; 124-38-9/Carbon Dioxide; 7782-44-7/Oxygen; 9007-49-2/DNA

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