Laboratory for Experimental Neurocardiology, Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia.
Mediterranean Institute for Life Sciences (MedILS), Meštrovićevo Šetalište 45, 21000 Split, Croatia.
Int J Mol Sci. 2023 Feb 3;24(3):2965. doi: 10.3390/ijms24032965.
We analyzed the expression of the serotonin receptors 5-HT1A, 5-HT2A, and 5-HT3A at four different stages of fetal lung development from 12 to 40 weeks of gestation, divided into four groups: the pseudoglandular stage (12-16th week of development; = 8), the canalicular stage (16th-26th week of development; = 7), the saccular stage (26th-36th week of development; = 5), and the alveolar stage (36th-40th week of development; = 5). The strongest expression of all three receptor types was found in the epithelium of the proximal airways during the pseudoglandular, canalicular, and saccular stages and in a vascular wall. 5-HT1A was also strongly expressed in the smooth muscle cells of the proximal airway. Vascular smooth muscle cells and endothelium occasionally showed a strong expression of 5-HT1A and 5-HT2A. In the alveolar stage, the expression of 5-HT1A, 5-HT2A, and 5-HT3A was detected in both type I (p1) and type II (p2) pneumocytes, with a stronger expression in p2. A significant decrease in percent the 5-HT2A area and in the integrated density was observed at the alveolar stage. On the other hand, a significant decrease in the percentage area but an increase in the integrated density was observed for 5-HT3A toward the alveolar stage, suggesting that a smaller number of cells expressed 5-HT3A but that they (p1 and p2) significantly increased their 5-HT3A expression at the alveolar stage. The results presented provided us with new data on the development and function of the serotonin system in the human fetal lung and gave us insight into their possible involvement in the pathogenesis of lung pathology, particularly that characteristic of the neonatal period.
我们分析了在妊娠 12 周到 40 周的胎儿肺发育的四个不同阶段中 5-羟色胺受体 5-HT1A、5-HT2A 和 5-HT3A 的表达情况，将其分为四个组：假腺期（发育的 12-16 周；n=8）、小管期（发育的 16-26 周；n=7）、囊泡期（发育的 26-36 周；n=5）和肺泡期（发育的 36-40 周；n=5）。在假腺期、小管期和囊泡期，所有三种受体类型在近端气道的上皮和血管壁中均有最强的表达。5-HT1A 也在近端气道的平滑肌细胞中强烈表达。血管平滑肌细胞和内皮细胞偶尔表现出 5-HT1A 和 5-HT2A 的强烈表达。在肺泡期，在 I 型（p1）和 II 型（p2）肺泡细胞中均检测到 5-HT1A、5-HT2A 和 5-HT3A 的表达，p2 中的表达更强。在肺泡期，5-HT2A 面积和积分密度的百分比显著下降。另一方面，5-HT3A 的面积百分比显著下降，但积分密度增加，这表明表达 5-HT3A 的细胞数量减少，但 p1 和 p2 在肺泡期显著增加了它们的 5-HT3A 表达。所提供的结果为我们提供了人类胎儿肺中 5-羟色胺系统发育和功能的新数据，并使我们深入了解它们在肺病理学发病机制中的可能作用，特别是在新生儿期的特征。
