Ruttenstock Elke Maria, Doi Takashi, Dingemann Jens, Puri Prem
National Children's Research Centre, Our Lady's Children's Hospital, Dublin 12, Ireland.
Pediatr Surg Int. 2011 Feb;27(2):125-9. doi: 10.1007/s00383-010-2783-2.
Pulmonary hypoplasia (PH), the leading cause of mortality in congenital diaphragmatic hernia (CDH), is associated with arrested alveolarization. Late gestation lung protein 1 (LGL1) plays a crucial role in the regulation of alveolarization. Inhibition of LGL1 impairs alveolar maturation in fetal rat lungs. LGL1 heterozygotus knockout mice display delayed lung maturation. It is well known that prenatal administration of retinoic acid (RA) stimulates alveologenesis in nitrofen-induced PH. In vitro studies have reported that RA is a key modulator of LGL1 during alveologenesis. We hypothesized, that pulmonary gene expression of LGL1 is downregulated in the late stage of lung development, and that prenatal administration of RA upregulates pulmonary LGL1 expression in the nitrofen CDH model.
Pregnant rats were exposed to nitrofen on day 9 (D9) of gestation. RA was given intraperitoneally on D18, D19 and D20. Fetal lungs were dissected on D21 and divided into control, control + RA, CDH and CDH + RA group. Expression levels of LGL1 were determined using RT-PCR and immunohistochemistry.
On D21, LGL1 relative mRNA expression levels were significantly downregulated in CDH group compared to controls. After RA treatment, gene expression levels of LGL1 were significantly upregulated in CDH + RA and control + RA compared to CDH group. Immunohistochemical studies confirmed these results.
Downregulation of pulmonary LGL1 gene expression in the late stage of lung development may interfere with normal alveologenesis. Upregulation of LGL1 pulmonary gene expression after RA treatment may promote lung growth by stimulating alveologenesis in the nitrofen CDH model.
肺发育不全（PH）是先天性膈疝（CDH）死亡的主要原因，与肺泡化停滞有关。妊娠晚期肺蛋白1（LGL1）在肺泡化调节中起关键作用。抑制LGL1会损害胎鼠肺的肺泡成熟。LGL1杂合子敲除小鼠表现出肺成熟延迟。众所周知，产前给予视黄酸（RA）可刺激在硝呋烯腙诱导的PH中的肺泡形成。体外研究报道，RA是肺泡形成过程中LGL1的关键调节因子。我们推测，在肺发育后期LGL1的肺基因表达下调，并且在硝呋烯腙CDH模型中产前给予RA可上调肺LGL1表达。
妊娠第9天（D9）的孕鼠暴露于硝呋烯腙。在D18、D19和D20腹腔注射RA。在D21解剖胎肺并分为对照组、对照组+RA、CDH组和CDH+RA组。使用逆转录-聚合酶链反应（RT-PCR）和免疫组织化学测定LGL1的表达水平。
在D21，与对照组相比，CDH组中LGL1相对mRNA表达水平显著下调。RA治疗后，与CDH组相比，CDH+RA组和对照组+RA组中LGL1的基因表达水平显著上调。免疫组织化学研究证实了这些结果。
肺发育后期肺LGL1基因表达下调可能会干扰正常的肺泡形成。在硝呋烯腙CDH模型中，RA治疗后肺LGL1基因表达上调可能通过刺激肺泡形成促进肺生长。
