Kutasy Balazs, Gosemann Jan H, Doi Takashi, Fujiwara Naho, Friedmacher Florian, Puri Prem
The National Children's Research Center, Our Lady's Children's Hospital, Dublin, Ireland.
Pediatr Surg Int. 2012 Feb;28(2):143-8. doi: 10.1007/s00383-011-2995-0.
Retinoids play a key role in lung development. Retinoid signaling pathway has been shown to be disrupted in the nitrofen model of congenital diaphragmatic hernia (CDH) but the exact mechanism is not clearly understood. Retinol-binding protein (RBP) and transthyretin (TTR) are transport proteins for delivery of retinol to the tissues via circulation. Previous studies have shown that pulmonary retinol levels are decreased during lung morphogenesis in the nitrofen CDH model. In human newborns with CDH, both retinol and RBP levels are decreased. It has been reported that maternal RBP does not cross the placenta and the fetus produces its own RBP by trophoblast. RBP and TTR synthesized in the fetus are essential for retinol transport to the developing organs including lung morphogenesis. We hypothesized that nitrofen interferes with the trophoblastic expression of RBP and TTR during lung morphogenesis and designed this study to examine the trophoblastic expression of RBP and TTR, and the total level of RBP and TTR in the lung in the nitrofen model of CDH.
Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs and placenta harvested on D21 and divided into two groups: control (n = 8) and nitrofen with CDH (n = 8). Total lung RBP and TTR levels using protein extraction were compared with enzyme linked immunoassay (ELISA). Immunohistochemistry was performed to evaluate trophoblastic RBP and TTR expression.
Total protein levels of lung RBP and TTR were significantly lower in CDH (0.26 ± 0.003 and 6.4 ± 0.5 μg/mL) compared with controls (0.4 ± 0.001 and 9.9 ± 1.6 μg/mL, p < 0.05). In the control group, immunohistochemical staining showed strong immunoreactivity of RBP and TTR in the trophoblast compared to CDH group.
Decreased trophoblast expression of retinol transport proteins suggest that nitrofen may interfere with the fetal retinol transport resulting in reduced pulmonary RBP and TTR levels and causing pulmonary hypoplasia in CDH.
维甲酸在肺发育中起关键作用。先天性膈疝（CDH）的硝呋烯腙模型显示维甲酸信号通路被破坏，但确切机制尚不清楚。视黄醇结合蛋白（RBP）和甲状腺素转运蛋白（TTR）是通过循环将视黄醇输送到组织的转运蛋白。先前的研究表明，在硝呋烯腙CDH模型的肺形态发生过程中，肺视黄醇水平降低。在患有CDH的人类新生儿中，视黄醇和RBP水平均降低。据报道，母体RBP不能穿过胎盘，胎儿通过滋养层产生自身的RBP。胎儿合成的RBP和TTR对视黄醇转运至包括肺形态发生在内的发育器官至关重要。我们假设硝呋烯腙在肺形态发生过程中干扰RBP和TTR的滋养层表达，并设计本研究以检测CDH硝呋烯腙模型中RBP和TTR的滋养层表达以及肺中RBP和TTR的总水平。
妊娠第9天（D9）将怀孕大鼠暴露于橄榄油或硝呋烯腙。在D21收集胎儿肺和胎盘并分为两组：对照组（n = 8）和患有CDH的硝呋烯腙组（n = 8）。使用蛋白质提取法测定肺RBP和TTR的总水平，并通过酶联免疫吸附测定（ELISA）进行比较。进行免疫组织化学以评估滋养层RBP和TTR的表达。
与对照组（0.4±0.001和9.9±1.6μg/mL，p <0.05）相比，CDH组肺RBP和TTR的总蛋白水平显著降低（0.26±0.003和6.4±0.5μg/mL）。在对照组中，免疫组织化学染色显示与CDH组相比，滋养层中RBP和TTR的免疫反应性更强。
视黄醇转运蛋白的滋养层表达降低表明，硝呋烯腙可能干扰胎儿视黄醇转运，导致肺RBP和TTR水平降低，并导致CDH中的肺发育不全。
