Effect of nitric oxide on the development of nitrofen-induced fetal hypoplastic lung explants

Background/Purpose

Nitric oxide (NO) is an important cell-signaling molecule, and its generators, nitric oxide synthases, are expressed temporospatially in fetal rat lung. Recently, NO has been reported to modulate branching of the fetal rat lung lobe in vitro. We designed this study to evaluate the effect of NO on the morphogenesis of hypoplastic lung using nitrofen-induced rat lung explant model.

Methods

A hypoplastic fetal lung model and a normal control lung model were induced by feeding a pregnant rat with nitrofen (100 mg) or olive oil on day 9.5 of gestation, respectively. Fetal lungs were harvested on day 13.5 and placed in organ culture containing serum-free medium Dulbecco modified Eagle medium. An NO donor, DETA NONOate (DETA/NO), was added daily in the culture medium. The lung cultures were divided into 4 groups: group 1 (n = 8), normal controls without DETA/NO; group 2 (n = 22), normal controls with DETA/NO; group 3 (n = 13), hypoplastic lungs without DETA/NO; group 4 (n = 22), hypoplastic lungs with DETA/NO. The fetal lungs were incubated for 48 hours at 37°C with 5% CO₂. Lung bud count and area of the specimens were measured under computer-assisted digital tracings. The rate of increase in bud count and lung area was calculated as the ratio of each value at 48 hours minus each value at 0 hour, divided by the value at 0 hour.

Results

The lung bud count was significantly increased in group 2 compared with group 1 at a concentration of 50 μmol/L DETA/NO (P < .05). In the nitrofen group, the lung bud count was significantly increased in group 4 compared with group 3 at 100 μmol/L DETA/NO added (P < .05). There was no significant difference in the rate of increase in whole lung area among the 4 groups. The peak increase rates of lung area and bud count were significantly lower in group 4 compared with group 2.

Conclusions

This study demonstrates that the NO donor, DETA/NO, promotes branching of the nitrofen-induced hypoplastic fetal lung explant. These data suggest that NO may modulate the development of the nitrofen-induced hypoplastic lung.     

Prenatal treatment with retinoic acid promotes pulmonary alveologenesis in the nitrofen model of congenital diaphragmatic hernia

Background/Purpose

Severe pulmonary hypoplasia remains the main cause of the high mortality in newborn infants with congenital diaphragmatic hernia (CDH). Retinoids are a family of molecules derived from vitamin A, which play an important role in lung development. We hypothesized that retinoids promote alveologenesis at the end of gestation and therefore designed this study to investigate the effects of retinoid acid on nitrofen-induced hypoplastic lungs in CDH.

Methods

Pregnant rats were exposed to either olive oil or 100 mg nitrofen on day 9 of gestation. Retinoic acid 5 mg/kg was given intraperitoneally on days 18, 19, and 20 of gestation and fetuses were recovered on day 21. We had 4 study groups: control (n = 24), control + retinoic acid (n = 22), CDH (n = 24), and CDH + retinoic acid (n = 19). Lungs from the 4 study groups were fixed, and the following stereological measurements were performed on vertical random sections: total lung volume, volume density of airspaces, volume density of air walls, gas exchange surface area, alveolar volume, and total number of alveoli per lung. Total DNA content of each lung was measured using a spectrophotometer.

Results

Total lung volume increased in CDH lungs after the addition of retinoic acid but remained the same in the control group. Gas exchange surface area was larger in CDH lungs after the addition of retinoic acid but remained unchanged in the control group. The total number of alveoli per lung was higher after the addition of retinoic acid. Total DNA content as well as total DNA content-lung weight ratio of the left lung increased significantly in the CDH group after the addition of retinoic acid compared with CDH without retinoic acid.

Conclusions

Our results demonstrate that prenatal treatment with retinoic acid stimulates alveologenesis in hypoplastic lungs in CDH.     

Vitamin A improves Pax3 expression that is decreased in the heart of rats with experimental diaphragmatic hernia

Background/Aims

Rats with nitrofen-induced congenital diaphragmatic hernia (CDH) have hypoplasia and malformations of the heart. The mechanism of action of nitrofen involves changes in neural crest signaling. Pax3 function is required for cardiac neural crest cells to complete their migration to the developing heart. Vitamin A improves heart hypoplasia. The aims of this study were to examine whether Pax3 expression is decreased in the heart of E13 E15 and E21 rats exposed to nitrofen and if vitamin A reverts this effect.

Material and Methods

Pregnant rats received either 100 mg nitrofen or olive oil on E9.5. Each group was divided into 2 subgroups according to the subsequent treatment with intragastric vitamin A (15000 IU) or vehicle on E10.5 to E11.5. The pups were recovered on E13, E15 and E21 and the hearts were dissected out. Pax3 mRNA expression was determined by quantitative real time PCR. Comparisons among groups were made with ANOVA and Bonferroni post hoc tests with a threshold of significance of P < .05.

Results

Pax3 mRNA expression was significantly decreased on E13 and E15 in the hearts of nitrofen-treated embryos and it remained decreased although not significantly on E21. Vitamin A recovered this expression on E13, partially on E15 and above normal levels on E21.

Conclusions

Pax3 is underexpressed in the hearts of nitrofen exposed embryonal rats on days 13th and 15th of gestation and tends to be lower than normal near term. Vitamin A up-regulates this expression on the 3 end points. The mechanism of action of Pax3 should be further investigated because it could be one of the targets for future prenatal transplacental intervention.     

Kidney development in the nitrofen-induced pulmonary hypoplasia and congenital diaphragmatic hernia in rats

Background/Purpose

The relationship of the developing lung and kidney is not completely understood. Renal enlargement has been reported in association with pulmonary hypoplasia in congenital diaphragmatic hernia (CDH). Recent studies suggest that retinoids may be involved in the pathogenesis of CDH. The aims of this study were to investigate the effects of pulmonary hypoplasia on renal development and to evaluate retinoids status of kidneys in the nitrofen model of CDH.

Methods

Pregnant rats were exposed to either olive oil or 100 mg of nitrofen on day 9.5 of gestation. Fetuses were recovered at term and divided into 3 groups: 1, control (n = 69); 2, nitrofen without CDH (n = 25); and 3, nitrofen with CDH (n = 40). Kidneys were dissected, weighed, and processed for biochemical measurements of DNA, proteins, total retinol content, and for immunohistochemical staining of proliferating cells.

Results

Kidneys were smaller in nitrofen-exposed animals vs control animals (group 3, 0.65 ± 0.08; group 2, 0.62 ± 0.09 vs group 1, 0.73 ± 0.09% of body weight, P < .001), and there were no differences between right and left kidney weight in all the 3 groups. Regression of total kidney weight on body weight showed a linear direct correlation between them in all the groups. Total amount of DNA was significantly reduced in nitrofen-exposed animals vs controls (group 3, 80.58 ± 35.65; group 2, 64.71 ± 20.28 vs group 1, 110.34 ± 42.15 μg, P < .01), but the DNA concentration remained the same in the 3 groups (group 3, 3.59 ± 1.26; group 2, 3.06 ± 1.19; group 1, 3.43 ± 1.05 μg DNA/mg kidney). Total protein content (group 3, 1145.59 ± 500.36; group 2, 993.2 ± 276.62; group 1, 1287.48 ± 312.52 μg), protein concentration (group 3, 49.76 ± 11.12; group 2, 43.95 ± 6.79; group 1, 47.38 ± 6.93 μg protein/mg kidney), and protein-to-DNA ratio (group 3, 15.12 ± 5.98; group 2, 16.22 ± 6.85; group I, 16.16 ± 7.02 μg/μg) were similar in all groups. Retinol concentration was significantly reduced in both nitrofen-exposed groups compared with the control group (group 3, 1.35 ± 0.24; group 2, 1.28 ± 0.11; group 1, 2.53±0.61 μg retinol/g kidney). Proliferation index was similar in all 3 groups (group 3, 50.43 ± 8.81; group 2, 47.96 ± 6.01; group 1, 47.64 ± 5.76% of proliferating cells).

Conclusions

Our data clearly show that renal enlargement in association with pulmonary hypoplasia is not seen in the nitrofen-induced CDH. These results rule out any possible relationship between lung and kidney development. Moreover, kidneys are hypoplastic in both nitrofen-exposed groups and have reduced retinol content, suggesting that a retinoid pathway disruption could be the common mechanism in the pathogenesis of lung and kidney hypoplasia in the nitrofen model of CDH.     

Effect of VEGF on the branching morphogenesis of normal and nitrofen-induced hypoplastic fetal rat lung explants

Purpose

Changes in vascular structures as well as vascular endothelial growth factor (VEGF) downregulation have been reported in hypoplastic lungs associated with congenital diaphragmatic hernia. We hypothesized that VEGF may accelerate branching morphogenesis and thus may modulate lung growth in normal and nitrofen-induced pulmonary hypoplastic lungs.

Methods

A hypoplastic fetal lung model and a normal control lung model were induced by feeding pregnant rats with or without nitrofen, respectively. Fetal lungs harvested on day 13.5 were cultured at ambient oxygen tensions for 72 hours with 0, 25, 50, or 100 ng/mL of exogenous rat VEGF added daily in the serum-free medium. The rates of increase in bud count and airway contour were evaluated. Real-time polymerase chain reaction was carried out to evaluate the expression of surfactant protein C mRNA in the explants at the end of culture.

Results

Vascular endothelial growth factor accelerated the increase in bud count and airway contour in normal and hypoplastic lung explants compared to controls. Surfactant protein C mRNA expression was significantly increased at 50 ng/mL VEGF compared to controls in both normal and hypoplastic lung explants.

Conclusion

These data suggest that VEGF plays an important role in lung morphogenesis and may accelerate lung growth in nitrofen-induced hypoplastic lung.     

Administration of prenatal betamethasone suppresses the adrenal-hypophyseal axis in newborns with congenital diaphragmatic hernia

Background

Congenital diaphragmatic hernia (CDH) is a condition that is characterized by pulmonary hypoplasia and pulmonary hypertension. Prenatal betamethasone often is administered to fetuses with CDH to improve pulmonary function. In this study, the authors investigate the possible role of the adrenal-hypophyseal axis in CDH in an animal model and subsequently in human infants with CDH.

Methods

Twin fetal sheep underwent creation of DH or a sham thoracotomy, and levels of plasma and lung ACTH and plasma cortisol were compared. For the human studies, plasma levels of ACTH, cortisol, and DHEA were measured in cord blood samples collected from 9 CDH (5 that received prenatal betamethasone) and compared with those of 14 normal newborns. In both studies, ACTH and cortisol levels were determined by radioimmunoassay (RIA). Human (DHEA) levels were determined by ELISA.

Results

Plasma ACTH and cortisol levels were elevated in fetal DH sheep compared with sham-operated controls; however, levels of ACTH in lung tissues were not different. Human newborns with CDH who have been exposed to prenatal steroids have significantly lower plasma ACTH, cortisol, and DHEA levels than normal newborns and CDH newborns not exposed to prenatal betamethasone.

Conclusions

In an ovine model of CDH, the adrenal-hypophyseal axis appears up-regulated in DH fetuses compared with sham-operated animals. Conversely, the adrenal-hypophyseal axis in human CDH newborns appears normal but is suppressed by the administration of prenatal betamethasone.     

Current consequences of prenatal diagnosis of congenital diaphragmatic hernia

Background

Today, the diagnosis of congenital diaphragmatic hernia (CDH) can readily be made in the prenatal period during screening ultrasound examination. Patients ought to be referred to rule out associated anomalies, and in isolated cases, prognosis is poor when the liver is intrathoracic and the lung-to-head ratio (LHR) is less than 1. In these patients, prenatal intervention aiming to reverse pulmonary hypoplasia can be considered.

Methods

We present our current algorithm for counselling patients presenting with CDH. Patients with a poor prognosis are offered percutaneous fetal endoluminal tracheal occlusion (FETO) with a balloon, inserted at 26 to 28 weeks. We report on the evolution of technique and results in a consecutive homogeneous case series and compare outcome in cases with similar severity managed in the postnatal period.

Results

Within a period of 28 months, FETO was performed between 26 and 28 weeks in 24 fetuses with severe left-sided CDH. Under general (n = 5), epidural (n = 17) or local (n = 2) anesthesia, the balloon was successfully positioned at first surgery (23/24) with a mean operation time of 20 minutes (range, 3-60 minutes). There were no serious maternal complications or direct fetal adverse effects. In the first 2 weeks after FETO, LHR increased from 0.7 to 1.7. Premature prelabour rupture of the membrane (PPROM) occurred in 16.7% and 33.3% at 28 and 32 weeks or earlier, respectively. Gestational age at delivery was 33.5 weeks. Patency of airways was restored either in the prenatal (n = 12) or perinatal period (n = 12). Early (7 days) and late (28 days) survival, and survival at discharge were 75% (18/24), 58.3% (14/24) and 50% (12/24), respectively. Half of nonsurvivors (n = 6) died of pulmonary hypoplasia and hypertension, in combination with PPROM and preterm delivery (n = 4) and balloon dislodgement (n = 2), which coincided with a short tracheal occlusion (TO) period (12 days). In the other 6, TO period was comparable to that in the 12 survivors (47 vs 42 days, respectively). In that group of 6 babies, only 2 died of pulmonary problems. Late neonatal survival (28 days) was higher with prenatal vs perinatal balloon retrieval 83.3% vs 33.3% (P = .013). In a multicentre study validating the criteria, survival till discharge in 37 comparable cases was 9% (3/32) and 13% (5/37) of parents opted for termination.

Conclusion

Fetuses with isolated left-sided CDH, liver herniation, and LHR of less than 1 have a poor prognosis. Percutaneous FETO is minimally invasive and may improve the outcome in these highly selected cases. Airways can be restored before birth, allowing vaginal delivery and return to the referring tertiary unit and may improve survival rate. The procedure carries a risk for PPROM, although that may decrease with experience.     

Prenatal retinoic acid increases lipofibroblast expression in hypoplastic rat lungs with experimental congenital diaphragmatic hernia

Background/purpose

Prenatal administration of all-trans retinoic acid (ATRA) has been shown to stimulate alveolarization in nitrofen-induced pulmonary hypoplasia (PH) associated with congenital diaphragmatic hernia (CDH). Lipid-containing interstitial lipofibroblasts (LIFs), characterized by adipocyte differentiation-related protein (ADRP), play a critical role in alveolar development by coordinating lipid homeostasis. Previous studies have demonstrated that ATRA positively affects LIF expression in developing lungs. We hypothesized that pulmonary LIF expression is increased after prenatal ATRA treatment in the nitrofen model of CDH-associated PH.

Methods

Timed-pregnant rats were treated with nitrofen or vehicle on E9.5, followed by injection of ATRA or placebo on E18.5, E19.5, and E20.5. Fetal lungs were dissected on E21.5 and divided into Control + Placebo, Control + ATRA, Nitrofen + Placebo, and Nitrofen + ATRA. Pulmonary gene expression levels of ADRP were analyzed by quantitative real-time polymerase chain reaction, and LIF expression was investigated by ADRP immunohistochemistry, oil-red-O-, and immunofluorescence-double-staining.

Results

Relative mRNA expression of pulmonary ADRP was significantly increased in Nitrofen + ATRA compared to Nitrofen + Placebo (0.31 ± 0.02 vs. 0.08 ± 0.01; P < 0.0001). ADRP immunoreactivity and oil-red-O-staining were markedly increased in alveolar interstitium of Nitrofen + ATRA compared to Nitrofen + Placebo. Immunofluorescence-double-staining confirmed markedly increased LIF expression in alveolar walls of Nitrofen + ATRA compared to Nitrofen + Placebo.

Conclusions

Increased LIF expression after prenatal treatment with ATRA in nitrofen-induced PH suggests that ATRA may have a therapeutic potential in attenuating CDH-associated PH by stimulating alveolar development.     

Lung function and pulmonary artery blood flow following prenatal maternal retinoic acid and imatinib in the nitrofen model of congenital diaphragmatic hernia

Background

Lung and pulmonary vascular maldevelopment in congenital diaphragmatic hernia (CDH) results in significant morbidity and mortality. Retinoic acid (RA) and imatinib have been shown to improve pulmonary morphology following prenatal administration in the rat nitrofen-induced CDH model. It remains unclear if these changes translate into improved function. We evaluated the effect of prenatal RA and imatinib on postnatal lung function, structure, and pulmonary artery (PA) blood flow in the rat CDH model.

Effect of epidermal growth factor on pulmonary hypoplasia in experimental diaphragmatic hernia

Background/purpose

Currently, tracheal occlusion (TO) is a potent stimulus for fetal lung growth but also a rather invasive and high-risk procedure. The aim of this study was to investigate a new and much less invasive therapeutic strategy, namely the maternal intraperitoneal administration of epidermal growth factor (EGF) and its effect on pulmonary hypoplasia in the nitrofen-induced congenital diaphragmatic hernia (CDH) rat model, especially its effect on type II pneumocytes.

Methods

CDH was induced by maternal administration of a single oral dose (100 mg) of nitrofen on day 8.5 of pregnancy. Four groups of pregnant rats were designed on day 18.5: normal control (n = 4), CDH (n = 4), CDH plus Dex (n = 4), CDH plus EGF (n = 8). All fetuses were delivered by cesarean section on day 21. Accordingly, there were 4 groups of fetuses: normal controls (n = 33), nitrofen-induced CDH (n = 19), CDH plus Dex treatment (n = 15), and CDH plus EGF treatment (n = 24). Lung tissue weight (LW) and body weight (BW) of each fetus were recorded, lung histologic and morphometric evaluations were performed, and image analysis was combined after lung processing. Transmission electron microscopy was used for ultrastructural observation, especially type II pneumocytes.

Results

CDH was observed in 58 of the 94 rat fetuses (61.7%). Lw/Bw of CDH group was significantly lower than those of Dex and EGF (P < .05). The lungs of CDH fetuses showed marked hypoplasia, in contrast to improved mesenchymal differentiation in that of Dex and EGF fetuses. Statistical differences of these morphologic parameters (RAC, MTBD, interstitial%, and alveoli%) were found (P < .05). As to ultrastructural features, type II cells of CDH lungs had few if any lamellar bodies and cytoplasmic organelles, and showed evidence of abundant glycogen granules. The sparse type II cells also showed cytoplasmic degenerative changes. By contrast, type II cells of EGF lungs showed numerous mitochondria, abundant lamellar bodies (surfactant) and deficiency of glycogen granules, and displayed prominent microvillous projections and pitlike depressions. The density of type II pneumocyte were 65 ± 4.5, 31 ± 3.1, and 8 ± 1.5 for EGF, Dex, and CDH, respectively (EGF v Dex, P < .05; EGF v CDH, P < 0.01).

Conclusions

Compared with TO, prenatal EGF administration as a much less-invasive therapeutic strategy had shown marked improvement in pulmonary hypoplasia and promotion of type II pneumocyte differentiation in the nitrofen-induced CDH rat model. Thus, EGF could improve the prognosis of CDH by means of promoting pulmonary hypoplasia and improving the surfactant deficiency, which suggested a potential role in the clinical treatment of CDH.     

The effect of in vitro tracheal occlusion on branching morphogenesis in fetal lung explants from the rat nitrofen model of congenital diaphragmatic hernia

Background/Purpose

Fetal tracheal occlusion (TO) has been investigated as a treatment option for lung hypoplasia secondary to congenital diaphragmatic hernia. Tracheal occlusion has been shown to accelerate lung growth, but its effect on bronchial branching is unknown. In this study, we characterize the effects of in vitro TO on bronchial branch development in fetal lung explants derived from the nitrofen rat model of congenital diaphragmatic hernia.

Methods

Rat dams were gavaged nitrofen on gestational day 9.5, and fetal lungs were harvested for explant culture on gestational day 14 (term, 22 days). Four experimental groups were investigated, with TO performed ex vivo using cautery: control, control + TO, nitrofen, and nitrofen + TO. Explants were incubated for 72 hours. Representative photographs were taken at 0, 24, 48, and 72 hours from the time of culture, and the number of distal branches was counted for each explant. The Student t test was used to compare distal branch measurements.

Results

A minimum of 12 fetal lung explants were cultured for each group. By 24 hours, all explants undergoing TO had more branch iterations than explants that did not. Moreover, TO in nitrofen-exposed explants increased bronchial branching to control levels by 24 hours in culture.

Conclusion

Our results suggest that TO at day 14 increases branching in normal and nitrofen-exposed lung explants. In addition, TO increases airway branching in nitrofen-exposed explants to control levels suggesting that early TO reverses the lung hypoplasia seen in this model.     

Diagnosis and management of fetal intrapericardial Morgagni diaphragmatic hernia with massive pericardial effussion

Herniation of the liver into the fluid-filled pericardial sac resulting in a thoracic mass is a particularly rare form of Morgagni hernia (congenital diaphragmatic hernia of Morgagni). We report an early antenatal diagnosis of congenital diaphragmatic hernia of Morgagni with pericardium effussion at 21 weeks' gestation. Two pericardiocentesis were performed at 21 and 22 4/7 weeks' gestation because of recurrence of pericardial effussion. Regular ultrasound assessments showed progressive herniation of the liver to practically fill the right hemithorax. An ex utero intrapartum treatment procedure was performed at 37 weeks' gestation to rescue maximum intrathoracic space for ventilation of the remaining functional lung tissue and to establish an airway for postnatal support. After birth, the patient successfully underwent early correction of the hernia. Postoperative course was uneventful, and the newborn girl was discharged 18 days later without complications and is currently doing well.     

Technical aspects of fetal endoscopic tracheal occlusion for congenital diaphragmatic hernia

In isolated congenital diaphragmatic hernia, prenatal prediction is made based on measurements of lung size and the presence of liver herniation into the thorax. A subset of fetuses likely to die in the postnatal period is eligible for fetal intervention that can promote lung growth. Rather than anatomical repair, this is now attempted by temporary fetal endoscopic tracheal occlusion (FETO). Herein we describe purpose-designed instruments that were developed thanks to a grant from the European Commission. The feasibility and safety of FETO have now been demonstrated in several active fetal surgery programs. The most frequent complication of the procedure is preterm premature rupture of the membranes, which is probably iatrogenic in nature. It does have an impact on gestational age at delivery and complicates balloon removal. FETO is associated with an apparent increase in survival compared with same severity controls, although this needs to be evaluated in a formal trial. The time has come to do so.     

Congenital heart disease associated with congenital diaphragmatic hernia: A systematic review on incidence,prenatal diagnosis,management, and outcome

PurposeThe purpose of this study was to evaluate the impact of congenital heart disease (CHD) on infants with congenital diaphragmatic hernia (CDH).MethodsUsing a defined search strategy (PubMed, Cochrane, Embase, Web of Science MeSH headings), we searched studies reporting the incidence, management, and outcome of CDH infants born with associated CHD.ResultsOf 6410 abstracts, 117 met criteria. Overall, out of 28,974 babies with CDH, 4427 (15%) had CHD, of which 42% were critical. CDH repair was performed in a lower proportion of infants with CHD (72%) than in those without (85%; p < 0.0001). Compared to CDH babies without CHD, those born with a cardiac lesion were more likely to have a patch repair (45% vs. 30%; p < 0.01) and less likely to undergo minimally invasive surgery (5% vs. 17%; p < 0.0001). CDH babies with CHD had a lower survival rate than those without CHD (52 vs. 73%; p < 0.001). Survival was even lower (32%) in babies with critical CHD.ConclusionCHD has a strong impact on the management and outcome of infants with CDH. The combination of CDH and CHD results in lower survival than those without CHD or an isolated cardiac defect. Further studies are needed to address some specific aspects of the management of this fragile CDH cohort.Type of studySystematic review and meta-analysis.Level of evidenceLevel III.     

Increased uptake of dietary retinoids at the maternal-fetal barrier in the nitrofen model of congenital diaphragmatic hernia

Background/Purpose

The retinol signaling pathway is disrupted in congenital diaphragmatic hernia (CDH). Since there is no fetal retinol synthesis, maternal retinol has to cross the placenta. Nitrofen interferes with the retinol-binding protein (RBP) transfer pathway in CDH. However, in RBP knockout mice, retinol has been shown to be present. In this model, increased uptake of maternal dietary retinyl ester (RE) bounded in low-dense-lipoprotein (LDL) through low-density-lipoprotein-receptor 1 (LRP1) and increased activity of RE hydrolysis by lipoprotein-lipase (LPL) have been found. The aim of this study was to investigate the RE transfer pathway in the nitrofen CDH model.

Methods

Pregnant rats were treated with nitrofen or vehicle on gestational day (D9) and sacrificed on D21. Immunohistochemistry was performed to evaluate LRP1 and LPL protein expression. Serum LDL levels were measured by ELISA. Pulmonary and serum retinoid levels were measured using HPLC.

Results

Markedly increased trophoblastic and pulmonary LRP1 and LPL immunoreactivity were observed in CDH compared to controls. Significantly increased serum LDL and RE levels were observed in CDH compared to controls.

Conclusions

The increased uptake of dietary retinoids at the maternal-fetal barrier in the nitrofen CDH model suggests that the RE transfer pathway may be the main source of retinol in this model.     

Effects of estrogen on lung development in a rat model of diaphragmatic hernia

PurposeThe study aimed to observe the influence of estradiol on rat models with congenital diaphragmatic hernia (CDH) and understand the potential mechanism.MethodsEleven pregnant female Sprague-Dawley rats were randomly divided into 3 groups on day 9.5 of gestation: group C (n = 2) was administered 2 mL of olive oil, whereas group N (n = 3) and group E (n = 6) were administered 200 mg of nitrofen. Antenatal estradiol was given subcutaneously to group E on days 18.5, 19.5, and 20.5 of gestation. Histologic evaluations, incidence of CDH, and the immunoreactivity of transforming growth factor (TGF)-β1 in lung were observed. In addition, the mRNA levels of TGF-β1, type I TGF-β receptor (TβRI), and type II TGF-β receptor (TβRII) were determined.ResultsHistologically, the lungs of group N fetuses were hypoplastic compared with those of group C and had thick-walled septa with poorly developed saccules. Group E showed improved mesenchymal differentiation with well-developed saccules. There was no significant difference between the incidence of CDH in group N and that in group E. The expression of TGF-β1 in lung tissue and arterioles in group N were significantly higher than those in group C and E. Moreover, relative mRNA expression levels of TGF-β1 and TβRI in group N were markedly higher than those in group C, whereas those in group E were significantly decreased compared with group N.ConclusionsEstradiol can promote lung development in rats with CDH. The down-regulation of TGF-β1 and its signaling pathway may play a role in this effect.