Prenatal administration of retinoic acid upregulates connective tissue growth factor in the nitrofen CDH model.
OBJECTIVE
Recent studies have suggested that retinoids may be involved in the molecular mechanisms of pulmonary hypoplasia (PH) in congenital diaphragmatic hernia (CDH). Connective tissue growth factor (CTGF) plays a key role in foetal lung development and remodelling during later gestation. CTGF knockout mice exhibit PH with similar characteristics to the human and nitrofen-induced PH. Prenatal administration of retinoic acid (RA) has been shown to stimulate alveologenesis in nitrofen-induced PH. In vitro studies have revealed that RA can induce CTGF gene expression. We hypothesized that pulmonary gene expression of CTGF is downregulated during the later stages of lung development, and that prenatal administration of RA upregulates CTGF in the nitrofen CDH model.


METHODS
Pregnant rats were exposed to either olive oil or nitrofen on day 9 (D9) of gestation. RA was given intraperitoneally on D18, D19 and D20. Foetuses were harvested on D21 and divided into control, CDH, control + RA and CDH + RA group. Pulmonary CTGF gene and protein expression levels were determined using RT-PCR and immunohistochemistry.


RESULTS
On D21, CTGF relative mRNA expression levels were significantly downregulated in CDH group compared to controls. After RA treatment, expression levels of CTGF were significantly upregulated in CDH + RA and control + RA compared to the CDH group. Immunohistochemical studies confirmed these results.


CONCLUSIONS
Downregulation of pulmonary CTGF gene and protein expression during later stages of lung development may interfere with normal alveologenesis in the nitrofen CDH model. Upregulation of CTGF pulmonary gene expression after prenatal RA treatment may promote lung growth by promoting alveologenesis in the nitrofen-induced CDH model.
National Children's Research Centre, Our Lady's Children's Hospital, Dublin 12, Ireland.
Elke Maria
EM
Ruttenstock
Takashi
T
Doi
Jens
J
Dingemann
Prem
P
Puri
D000818:Animals; D055513:Connective Tissue Growth Factor / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics*; D004195:Disease Models, Animal; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D006548:Hernia, Diaphragmatic / Q000139:chemically induced / Q000235:genetics / Q000517:prevention & control; D065630:Hernias, Diaphragmatic, Congenital; D007150:Immunohistochemistry; D010647:Phenyl Ethers / Q000633:toxicity; D011247:Pregnancy; D011270:Pregnancy, Animal; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014212:Tretinoin / Q000008:administration & dosage*; D015854:Up-Regulation / Q000187:drug effects*
D010647:Phenyl Ethers; D012333:RNA, Messenger; D055513:Connective Tissue Growth Factor; D014212:Tretinoin; C007350:nitrofen
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