Abstract
Introduction: The nitrofen model of Congenital Diaphragmatic Hernia (CDH) displays a diaphragmatic
defect of the Bochdalek-type and has been widely used to investigate the pathogenesis
of CDH. However, the exact pathomechanism of the diaphragmatic defect is still poorly
understood. Fibroblast growth factor (FGF) receptor-like 1 (FGFRL1), a member of the
FGF receptor family, plays a key role in physiological diaphragmatic development.
FGFRL1 is expressed in the fetal diaphragm at low levels in early gestation and its
expression steadily increases, becoming most pronounced in later gestational stages.
It has been reported that FGFRL1 homozygous null mice have thin, partially amuscular
diaphragms and die at birth due to respiratory failure. The aim of this study was
to investigate the hypothesis that FGFRL1 gene expression in the diaphragm is downregulated
during the later gestational stages in the nitrofen CDH model.
Material and Methods: Timed pregnant rats were exposed to either olive oil or 100 mg nitrofen on day 9
of gestation (D9). Cesarean section was performed on D18 or D21. Fetal diaphragms
(n=40) were micro-dissected and divided into CDH group and controls. Total RNA was
extracted from the diaphragms and the mRNA levels of FGFRL1 were determined using
real-time PCR. Immunohistochemistry was performed to evaluate diaphragmatic protein
expression of FGFRL1. Student's t-test and Mann-Whitney test were used, where appropriate.
Statistical significance was considered for p<0.05.
Results: Relative mRNA expression levels of FGFRL1 were significantly decreased in the CDH
group compared to controls on D18 (3.63±1.65 vs. 6.04±3.12, p<0.05) and D21 (1.36±1.01
vs. 2.57±1.34, p<0.05). Immunoreactivity of FGFRL1 was markedly decreased in the diaphragms
of the CDH group compared to controls on D18 and D21.
Conclusion: Our data provide strong evidence that downregulation of the FGFRL1 gene during the
late stages of gestation may contribute to the development of the diaphragmatic defect
in nitrofen-induced CDH.
Key words
congenital diaphragmatic hernia - nitrofen - diaphragmatic defect - FGFRL1 - FGFR5
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Notice
This article was changed according to the following erratum on: 14.10.2010
Due to an inadvertent error on the side of the publisher, the article was published
online with the wrong author affiliations.
For all authors the affiliation is: Our Lady's Children's Hospital, National Children's
Research Centre, Dublin, Ireland.
Correspondence
Prof. Prem Puri
Our Lady's Children's Hospital
National Children's Research Centre
Crumlin
12 Dublin
Ireland
Phone: +353 01 4096 420
Fax: +353 01 4550 201
Email: prem.puri@ucd.ie
