The purpose of this study was to determine the effect of reversible fetal tracheal occlusion on lung development. Nine fetal sheep were divided into two groups. Group 1 had intratracheal balloons placed and the balloons left inflated for 21-28 days. Group 2 consisted of littermates that served as controls. They had either uninflated balloons placed or were left unoperated. Tracheal pressure measurements were periodically recorded and the amniotic fluid pressure served as a reference. The animals were sacrificed near term and the lungs, heart and liver were weighed and corrected for body weight. Standard morphometry was used to compare the lungs further and the lung DNA and protein content were measured. Tracheal damage from the balloon catheter was also assessed. / Tracheal pressure was 3.85 ($ pm$.49 S.E.) mm Hg in experimental animals while it was an average of $-$0.27 ($ pm$.27 S.E.) mm Hg in controls (p $<$.0001). Tracheal occlusion increased lung weight and volume by 2-3 times (p $<$.0001 and p =.0006, respectively) while heart and liver weights remained similar to controls. Airspace fraction and radial alveolar counts were raised (p =.044 and p =.0002, respectively) and alveolar number per body weight was doubled (p $<$.0001). The alveolar number per lung volume was preserved, however, as was the DNA and protein content per unit weight of lung tissue. The chronic indwelling balloon catheter caused some mucosal and submucosal damage at the balloon site and proximal to it. / These results show that tracheal occlusion leads to an elevation of intratracheal pressure that is associated with a tremendous increase in lung growth over a short period in the third trimester fetal sheep. The techniques used in this experiment may be easily modified for use with endoscopic surgical equipment.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.55500 |
| Date | January 1994 |
| Creators | Hashim, Ezat |
| Contributors | Laberge, J. M. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Division of Surgical Research.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001425982, proquestno: AAIMM00026, Theses scanned by UMI/ProQuest. |
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