Han R N, Liu J, Tanswell A K, Post M
Department of Paediatrics, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.
Microsc Res Tech. 1993 Dec 1;26(5):381-8. doi: 10.1002/jemt.1070260506.
There is increasing evidence that platelet-derived growth factor (PDGF) or PDGF-like molecules play a role in fetal lung morphogenesis. Our previous studies demonstrated the presence of PDGF-AA and PDGF-BB homodimers in fetal rat lung. To study further the target cells of PDGF in lung development, immunolocalization studies of PDGF receptors (PDGFR) were conducted on embryonic and fetal rat lung from day 13 to day 21 of gestation (term = 22 days) using two polyclonal PDGFR antibodies, one of which one recognizes both alpha and beta receptors (PDGFR-alpha/beta), while the other is specific for the beta receptor (PDGFR-beta). A similar immunostaining pattern for both antibodies was noted. Immunoreactivity to PDGFR was evident in both epithelial and mesenchymal cells of the embryonic lung bud as early as 13 days gestation. The number of PDGFR immunoreactive cells increased with advancing gestation. Intense immunoreactivity was noted in both epithelial cells and interstitial cells during the saccular stage of lung development. The immunoreactivity to PDGFR was localized to the apical/luminal side of bronchial and distal airway epithelial cells. PDGFR-immunopositive bronchial and vascular smooth muscle cells were detected only during the canalicular and saccular stages of lung development. Immunopositive endothelial cells lining the internal vascular plexuses were observed from days 14-16 of gestation. No PDGFR was detected in endothelial cells of large pulmonary vessels. We conclude that PDGFR are present in airway epithelial cells, interstitial cells, and bronchial and vascular smooth muscle cells and that gestation-dependent up- and down-regulation of PDGFR may play a role in developmental regulation of PDGF bioactivity during lung morphogenesis.
越来越多的证据表明，血小板衍生生长因子（PDGF）或PDGF样分子在胎儿肺形态发生中起作用。我们之前的研究证明了胎儿大鼠肺中存在PDGF-AA和PDGF-BB同二聚体。为了进一步研究PDGF在肺发育中的靶细胞，在妊娠第13天至第21天（足月为22天）的胚胎和胎儿大鼠肺上，使用两种多克隆PDGF受体（PDGFR）抗体进行了免疫定位研究，其中一种抗体可识别α和β受体（PDGFR-α/β），而另一种对β受体具有特异性（PDGFR-β）。两种抗体呈现出相似的免疫染色模式。早在妊娠13天时，胚胎肺芽的上皮细胞和间充质细胞中就明显存在对PDGFR的免疫反应性。随着妊娠进展，PDGFR免疫反应性细胞的数量增加。在肺发育的囊状期，上皮细胞和间质细胞中均观察到强烈的免疫反应性。对PDGFR的免疫反应性定位于支气管和远端气道上皮细胞的顶端/管腔侧。仅在肺发育的小管期和囊状期检测到PDGFR免疫阳性的支气管和血管平滑肌细胞。在妊娠第14 - 16天观察到内部血管丛衬里的免疫阳性内皮细胞。在大的肺血管内皮细胞中未检测到PDGFR。我们得出结论，PDGFR存在于气道上皮细胞、间质细胞以及支气管和血管平滑肌细胞中，并且PDGFR的妊娠依赖性上调和下调可能在肺形态发生过程中PDGF生物活性的发育调节中起作用。
