Platelet-derived growth factor and its receptor mRNA expressions are decreased in hypoplastic fetal rat lung due to oligohydramnios
Chung-Ming Chen, Leng-Fang Wang, Hsiu-Chu Chou
Department of Pediatrics, Taipei Medical University Hospital; Department of Biochemistry and Anatomy, College of Medicine, Taipei Medical University, Taipei, Taiwan
Background: Pulmonary hypoplasia is common in the perinatal period and oligohydramnios is one of the most common causes. Platelet-derived growth factor (PDGF) signaling is required for fetal alveologenesis.
Objective: To evaluate the role of PDGF in pulmonary hypoplasia due to oligohydramnios and to elucidate the mechanism by which oligohydramnios alters the fetal respiratory system.
Design/Methods: On day 16 of gestation, we anesthetized timed pregnant Sprague-Dawley dams, performed an abdominal midline incision, punctured the uterine wall and fetal membranes of each uterine sac using a 19-gauge needle, and resulted in oligohydramnios. Fetuses in the opposite uterine horn were served as controls. On days 19 (n=5) and 21 (n=4) of gestation, all dams were anesthetized and the fetuses were delivered by cesarean section. The fetuses were weighed and lungs were dissected free and weighed. We measured PDGF and PDGF receptor (PDGFR)-, PDGFR- genes expression by RT-PCR. Lung sections were stained with hematoxylin and eosin and radial saccular count was measured in fetuses delivered on day 21of gestation.
Results: Oligohydramniotic rats had significantly lower lung/body weight ratio on days 19 and 21 and significantly lower radial saccular count on day 21 than did the control rats. Oligohydramnios significantly decreased PDGF-A, -B, R-and - mRNA expressions on day 19 and significantly decreased PDGF-A and tended to decrease PDGF-B, R-and R- mRNA expressions on day 21.
Conclusions: Oligohydramnios decreases fetal lung growth and lung PDGF-A, -B, R-, R- mRNA expressions. These results indicate that PDGF is important for fetal lung development and provide useful therapeutic strategies for pulmonary hypoplasia induced by oligohydramnios.