Upregulation of endothelin receptors A and B in the nitrofen induced hypoplastic lung occurs early in gestation.
OBJECTIVE
Pulmonary hypoplasia and persistent pulmonary hypertension (PPH) aggravate clinical courses in congenital diaphragmatic hernia (CDH). Endothelin 1 enhances PPH by vasoconstriction and proliferation of vessel walls. Up-regulation of pulmonary Endothelin Receptors A and B (EDNRA, EDNRB) has been reported in human CDH and animal models, but the onset of those alterations during lung development remains unclear. We hypothesized that pulmonary expression of EDNRA and EDNRB is up-regulated at early gestational stages in the nitrofen model.


METHODS
Pregnant rats were exposed to nitrofen or vehicle on gestational day 9 (D9). Embryos were sacrificed on D15, D18 and D21 and divided into nitrofen- and control group. Pulmonary RNA was extracted and mRNA levels of EDNRA and EDNRB were determined by real-time PCR. Immunohistochemistry for protein expression of both receptors was performed.


RESULTS
mRNA levels of EDNRA and EDNRB were significantly increased in the nitrofen group on D15, D18 and D21. Immunohistochemistry revealed increased pulmonary vascular expression of EDNRA and EDNRB compared to controls.


CONCLUSIONS
Altered expression of EDNRA and EDNRB is an early event in lung morphogenesis in the nitrofen model. We speculate that pulmonary arteries in CDH become excessively muscularised in early fetal life, becoming unable to adapt normally at birth.
The Children's Research Centre, Our Lady's Children's Hospital, Dublin 12, Ireland.
Jens
J
Dingemann
Takashi
T
Doi
Elke
E
Ruttenstock
Prem
P
Puri
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005865:Gestational Age; D006548:Hernia, Diaphragmatic / Q000196:embryology / Q000235:genetics; D065630:Hernias, Diaphragmatic, Congenital; D007150:Immunohistochemistry; D008168:Lung / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D008171:Lung Diseases / Q000139:chemically induced / Q000150:complications / Q000235:genetics*; D010647:Phenyl Ethers / Q000633:toxicity; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A / Q000096:biosynthesis / Q000235:genetics*; D044023:Receptor, Endothelin B / Q000096:biosynthesis / Q000235:genetics*; D015854:Up-Regulation
D010647:Phenyl Ethers; D012333:RNA, Messenger; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; C007350:nitrofen