Gene expression of fibroblast growth factors 10 and 7 is downregulated in the lung of nitrofen-induced diaphragmatic hernia in rats.
OBJECTIVE
Newborns with congenital diaphragmatic hernia (CDH) still have a high mortality rate, which has been attributed to pulmonary hypoplasia and pulmonary hypertension. Fibroblast growth factors (FGFs) are essential components of the gene network that regulates lung development. Recent studies suggest that the new member of FGF family, FGF-10, plays a fundamental role in branching morphogenesis and is essential for lung formation. FGF-10-deficient mice exhibit complete absence of lungs. FGF-7 promotes epithelial proliferation and expansion leading to the formation of cystlike structures. The aim of this study was to determine the gene level expression of FGF-10 and FGF-7 in the lung of nitrofen-induced CDH.


METHODS
Congenital diaphragmatic hernia (CDH) was induced in pregnant rats after administration of 100 mg of nitrofen on day 9.5 of gestation (term, 22 days). In control animals, the same dose of olive oil was given without nitrofen. Cesarean section was performed on day 21 of gestation. The fetuses were divided into 3 groups: normal controls (n = 16), nitrofen induced without CDH (n = 16), and nitrofen-induced CDH (n = 16). Total RNA and DNA were extracted from the lung in each group and measured. mRNA was extracted from total RNA. Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate mRNA expressions of FGF-10 and FGF-7. Levels of mRNA were expressed as a ratio of the band density divided by that of beta-actin, a house-keeping gene.


RESULTS
FGF-10 mRNA expression was decreased significantly in CDH lung (2.914 +/- 0.320) compared with controls (4.062 +/- 0.307; P <.05) and nitrofen induced without CDH lung (3.923 +/- 0.250; P <.01). FGF-7 mRNA expression was decreased significantly in CDH lung (0.777 +/- 0.097) compared with controls (1.028 +/- 0.093; P <.01).


CONCLUSIONS
Decreased gene expression of FGF-10 and FGF-7 in the hypoplastic lung suggests that pulmonary hypoplasia in nitrofen-induced CDH rat may be caused by reduced synthesis of FGF-10 and FGF-7 during lung morphogenesis.
Teramoto
Honami
H
Children's Research Centre, Our Lady's Hospital for Sick Children, Dublin, Ireland.
Yoneda
Akihiro
A
Puri
Prem
P
D000818:Animals; D015536:Down-Regulation; D005315:Fetal Diseases; D051526:Fibroblast Growth Factor 10; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors / Q000096:biosynthesis*; D015870:Gene Expression; D006548:Hernia, Diaphragmatic / Q000139:chemically induced / Q000196:embryology*; D065630:Hernias, Diaphragmatic, Congenital; D008168:Lung / Q000002:abnormalities / Q000196:embryology* / Q000378:metabolism*; D023421:Models, Animal; D010647:Phenyl Ethers; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
C496465:Fgf10 protein, rat; C496455:Fgf7 protein, rat; D051526:Fibroblast Growth Factor 10; D010647:Phenyl Ethers; D012333:RNA, Messenger; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; C007350:nitrofen