Background: Pregnant women at a high risk of preterm delivery receive glucocorticoids to accelerate fetal lung maturation and surfactant synthesis. However, the effect of antenatal steroids on the developing diaphragm remains unclear. We hypothesized that maternal betamethasone impairs the fetal diaphragm, and the magnitude of the detrimental effect increases with longer duration of exposure. We aimed to determine how different durations of fetal exposure to maternal betamethasone treatment influence the fetal diaphragm at the functional and molecular levels.

Methods: Date-mated merino ewes received intramuscular injections of saline (control) or two doses of betamethasone (5.7 mg) at an interval of 24 h commencing either 2 or 14 days before delivery. Preterm lambs were killed after cesarean delivery at 121-day gestational age. In vitro contractile measurements were performed on the right hemidiaphragm, whereas molecular/cellular analyses used the left costal diaphragm.

Results: Different durations of fetal exposure to maternal betamethasone had no consistent effect on the protein metabolic pathway, expression of glucocorticoid receptor and its target genes, cellular oxidative status, or contractile properties of the fetal lamb diaphragm.

Conclusion: These data suggest that the potential benefits of betamethasone exposure on preterm respiratory function are not compromised by impaired diaphragm function after low-dose maternal intramuscular glucocorticoid exposure.

Item Type:	Refereed Article
Keywords:	diaphragm dysfunction, steriod exposure, fetal develoment
Research Division:	Medical and Health Sciences
Research Group:	Paediatrics and Reproductive Medicine
Research Field:	Foetal Development and Medicine
Objective Division:	Health
Objective Group:	Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:	Respiratory System and Diseases (incl. Asthma)
UTAS Author:	Song, Y (Dr Yong Song)
ID Code:	135698
Year Published:	2017
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2019-11-08
Last Modified:	2019-12-06
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