EFFECTS
OF TRH, EGF AND DEXAMETHASONE ON MORPHOGENESIS AND PHOSPHOLIPID LEVELS OF
FETAL LUNG IN RABBITS
Wang FY, Wang YM, Chang Q, Cao HW, Yang J, Xu DX, Shi CX
Southwest Hospital, Third Military Medical University, Chongqing, China
Objective£ºTo
compare the effects of thyrotropin-releasing hormone (TRH), epidermal
growth factor (EGF) and dexamethasone (Dex) on the morphogenesis and the
surfactant levels of premature fetal lungs.
Methods: Pregnant rabbits were intravenously injected with
TRH, EGF and Dex From 22th to 24th day or from 24th to 26th day of
gestation. The morphodifferentiation was observed and determined using a
light microscope with image capture system and electron microscope. The
phospholipid levels were detected by biochemical analysis.
Results: The development of alveoli and interalveolar
septa in TRH, EGF and Dex treated groups were significantly better than
that in the control group, and no significant difference was found among
these three treated groups at 27th day of gestation. The ultrastuctural
features of fetal lungs at 27th. day of gestation showed that the numbers
of alveolar type II cells containing lamellar bodies were apparently more
compared with that in the control group. However, lamellar body was rarely
found and abundant glycogen were seen in alveolar type II cells at 25th day
of gestation in all groups. In addition, the phospholipid levels in the
three treated groups were higher than that in the control group.
Conclusion: Prenatal maternal treatment With TRH, EGF and
Dex from 24th to 26th day of gestation can promote the morphogenesis and
increase the surfactant levels of premature fetal lung, but from 22th to
24th day, TRH, EGF and Dex Can only accelerate the structural development,
but no effect on the differentiation of alveolar type II cells and the
surfactant levels.