Ultrastructural changes of pulmonary arteries in nitrofen-induced congenital diaphragmatic hernia rats

Abstract

Objective To study the ultra-structural changes of pulmonary arterioles in nitrofeninduced congenital diaphragmatic hernia (CDH) rats. Methods Four pregnant SD rats were divided into two groups (Control and Model). CDH was induced in fetal rats by administration of 125 mg nitrofen (dissolved in 2.5ml olive oil) via gavage on E9. 5. The control group received the solvent. On E21, the fetuses were delivered by Cesarean section. Microstructure and image analysis evaluations of small pulmonary vessels were performed. Ultrastructure of intra-acinar pulmonary arteries (IAPA) was examined with transmission electron microscope. Results CDH were detected in 14 out of 23 fetuses in model group (60.9%). In the pre-acinar pulmonary arteries (PAPA), the model group fetuses had a significantly increased mucosal thickness (MT%) compared to the control group (P<0.01). MT% was also increased in the IAPA. The difference of MT% in PAPA and IAPA were statistically significant (P<0.01). The muscularized arteries (MA) and partially muscularized arteries (PMA) were found in the alveoli. Ultrastructrural examination showed proliferation of medial smooth muscle cells of arteries in model group, and also the proliferation and degeneration of endothelial cells were observed. The elastic laminar was irregular. Pulmonary arteriolar walls were disorganized. Conclusions The proliferation of smooth muscle cells, muscularization and disorganization of LAPA walls are characteristic ultrastructural changes of pulmonary vasculars in CDH models, and it might play an important role in the pathogenesis of CDH-related persistent pulmonary hypertension. Key words: Hernia, diaphragmatic; Lung diseases, congenital; Models, animal