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TGF-beta2 is increased after fetal tracheal occlusion
T M Quinn1, K G Sylvester, Y Kitano
1The Children's Institute for Surgical Science, The Children's Hospital of Philadelphia, and the University of Pennsylvania School of Medicine, 19104, USA.
Journal of Pediatric Surgery
|June 8, 1999
Summary
Fetal tracheal occlusion (TO) increases transforming growth factor-beta 2 (TGF-beta2) protein in fetal sheep lungs, potentially explaining accelerated lung growth. This study is the first to show altered growth factor protein levels after TO.
Area of Science:
- Fetal Surgery
- Pulmonary Biology
- Growth Factor Signaling
Background:
- Fetal tracheal occlusion (TO) accelerates lung growth, but the underlying mechanisms are not fully understood.
- Growth factor induction is a potential mechanism, yet previous studies focused on mRNA, not protein expression.
- The role of the transforming growth factor-beta (TGF-beta) family in TO-induced lung growth is unclear.
Purpose of the Study:
- To investigate whether TGF-beta expression is increased after fetal tracheal occlusion (TO).
- To determine if TGF-beta contributes to the accelerated lung growth observed following TO.
- To analyze both mRNA and protein levels of TGF-beta in response to TO.
Main Methods:
- Diaphragmatic hernia (DH) was created in fetal sheep, followed by tracheal occlusion (TO) in a subset of animals.
- Lung tissue samples were collected at term for analysis.
- TGF-beta mRNA was quantified using reverse transcriptionase-polymerase chain reaction (RT-PCR).
- TGF-beta protein levels were assessed via Western blot analysis.
Main Results:
- Tracheal ligation did not increase TGF-beta1 mRNA or protein levels compared to controls.
- A significant increase in both TGF-beta2 mRNA and protein was observed in ligated lungs.
- The elevation of TGF-beta2 suggests a specific role in the response to tracheal occlusion.
Conclusions:
- Fetal tracheal occlusion elevates TGF-beta2 protein, but not TGF-beta1, in hypoplastic sheep lungs.
- Increased TGF-beta2 expression likely results from sustained mRNA transcription.
- This finding provides the first evidence of altered growth factor protein levels post-TO and suggests TGF-beta2's involvement in accelerated lung growth and reduced surfactant production.