Effect of prenatal steroidal inhibition of sPLA2 in a rat model of preterm lung

Abstract

IntroductionSecretory phospholipase A2 regulates surfactant catabolism and inflammatory cascade. This enzyme is correlated with compliance, oxygenation and major outcomes in various forms of acute respiratory failure. Steroids inhibit secretory phospholipase A2 in cell culture and are widely used to boost surfactant production before preterm delivery. No data are available about the effect of antenatal steroids on secretory phospholipase A2 in the offspring: we aimed to study this effect in a rat model of preterm lung. Material and methodsFifteen pregnant Wistar rats were randomized to receive betamethasone, dexamethasone or placebo at 20 and 21 days gestation. Newborn rats were supported for 8 h and then sacrificed: lung tissue was analysed for secretory phospholipase A2 expression and activity, inflammatory mediators and protein content. Lipidomics was analysed using liquid chromatography-mass spectrometry. ResultsSecretory phospholipase A2 expression was significantly reduced by antenatal steroids (p < 0.001). Secretory phospholipase A2 activity, TNFα and lysophosphatidylethanolamine, a product of phospholipase reaction, were lowest in betamethasone-treated rats (p < 0.001). There was a strong correlation between secretory phospholipase A2 activity and lysophosphatidylethanolamine (r = 0.75; p = 0.001) and this remained significant after adjustment for total proteins or phospholipids. ConclusionsAntenatal steroids decrease secretory phospholipase A2 in rat model of preterm lung.