title: Disturbance of retinol transportation causes nitrofen-induced hypoplastic lung.
abstract: OBJECTIVE
  Retinoids play a key role in lung development. Recent studies suggest that retinoid signalling pathway may be disrupted in the nitrofen model of congenital diaphragmatic hernia (CDH), but the exact mechanism is not clearly understood. We hypothesized that nitrofen interferes with cellular uptake of retinol during lung morphogenesis and therefore designed this study to examine total retinol levels in lung, liver, and serum, and the gene expression of main components of the retinoid pathway in the nitrofen model of CDH.
  
  
  METHODS
  Pregnant rats were exposed to vehicle or 100 mg of nitrofen on day 9 of gestation. Term fetuses were divided in control and nitrofen with CDH and without CDH groups. Retinol levels in serum, lungs, and liver were measured using high-performance liquid chromatography. Reverse transcriptase-polymerase chain reaction was performed to evaluate the relative amount of cellular retinol-biding protein I, retinal dehydrogenase 1a2 and 1a3 (Aldh1a2 and Aldh1a3), retinoic acid receptors alpha and beta (RARalpha, RARbeta), and retinoid X receptor alpha (RXRalpha) expression in the lung.
  
  
  RESULTS
  Total retinol levels in the lungs were significantly lower in both nitrofen with CDH (1.78 +/- 0.37 microg/g) and nitrofen without CDH (1.61 +/- 0.24 microg/g) groups compared with controls (2.43 +/- 0.31 microg/g) (P < .001), whereas serum retinol levels were significantly higher in nitrofen with and without CDH groups (0.77 +/- 0.13 and 0.75 +/- 0.11 microg/g, respectively) compared with controls (0.58 +/- 0.12 microg/g) (P < .001). There was no significant difference in liver retinol levels between the 3 groups. Relative expression of cellular retinol-biding protein I, Aldh1a3, RARalpha, RARbeta, and RXRalpha were significantly up-regulated in the lungs of the nitrofen with CDH group (0.70 +/- 0.15, 3.94 +/- 0.91, 2.15 +/- 0.47, 3.49 +/- 1.00, 1.88 +/- 0.42, respectively) and the nitrofen without CDH group (0.61 +/- 0.14, 3.72 +/- 0.31, 1.66 +/- 0.20, 3.28 +/- 1.02, 1.38 +/- 0.24, respectively) compared with controls (0.43 +/- 0.11, 2.71 +/- 0.47, 0.79 +/- 0.42, 1.85 +/- 0.69, 0.57 +/- 0.22, respectively) (P < .05).
  
  
  CONCLUSIONS
  Our data clearly show that lung retinol storage is decreased in the nitrofen model of CDH. The associated increase in gene expressions of most downstream components of the retinoid signalling pathway may be a feedback reaction to the deficiency of lung retinol. These results suggest that nitrofen acts by interfering with the cellular uptake of retinol during lung morphogenesis resulting in pulmonary hypoplasia in this model.
authors.affiliation: The Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland.
authors.forename: Nana
authors.initials: N
authors.lastname: Nakazawa
authors.forename: Sandra
authors.initials: S
authors.lastname: Montedonico
authors.forename: Hajime
authors.initials: H
authors.lastname: Takayasu
authors.forename: Francesca
authors.initials: F
authors.lastname: Paradisi
authors.forename: Prem
authors.initials: P
authors.lastname: Puri
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D002851:Chromatography, High Pressure Liquid; D004195:Disease Models, Animal; D005260:Female; D006548:Hernia, Diaphragmatic / Q000139:chemically induced; D008168:Lung / Q000002:abnormalities* / Q000196:embryology; D008171:Lung Diseases / Q000196:embryology* / Q000503:physiopathology; D009024:Morphogenesis / Q000187:drug effects / Q000502:physiology; D010647:Phenyl Ethers / Q000494:pharmacology; D011247:Pregnancy; D011270:Pregnancy, Animal; D012333:RNA, Messenger; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D015398:Signal Transduction; D014801:Vitamin A / Q000032:analysis / Q000378:metabolism*
chemical_list: D010647:Phenyl Ethers; D012333:RNA, Messenger; D014801:Vitamin A; C007350:nitrofen