The Effects And Mechanism Of Single And Multiple Courses Of Antenatal Dexamethasone And Ambroxol On The Expression Of SP-BmRNA And TTF-1 In The Rat Fetal Lung

Objective: Neonatal respiratory distress syndrome(NRDS) caused by the deficiency of pulmonary surfactant is a fetal disease which often leads to the early health of newborns. Scholars studied it pathogenesis and preventions. Dexamethasone plays an important role in preventing NRDS because it can accelarate synthesis of PS and the maturation of fetal lung. The administration of Dex has many contraindications and side effcts, so it is necessary to look for an drug to substitute for Dex. Recently research found that ambroxol can accelarate the PS synthesis and secretion. But antenatal ambroxol aiming to prevent NRDS is seldom reported at home and abroad. Many obstetricians administrate multiple courses of antenatal Dex on pregnant women if they don't deliver after they received single course 7days ago. Now, the necessity and security of multiple courses is still controvertible. Thyroid transcription factor-1(TTF-1) mediates the transcription of SP gene and we found Dex can stimulate the TTF-1 gene by cell culture. To explore the mechanism of Dex's accelaration of SP through TTF-1 in vivo is not reported. This research build rat...