Different effects on pulmonary VEGF expression andseptation in newborn rats with prenataldexamethasone and betamethasone

Abstract

Betamethasone might be a better choice than dexameth-asone for antenatal therapy. Vascular endothelial growthfactor (VEGF) is critical for normal lung development. Theaim is to evaluate differences between dexamethasone andbetamethasone in the expression of VEGF and its reper-cussions in septation during rat lung development underoxidative stress.Methods: Dexamethasone or betamethasone wereadministered to gestant Wistar rats. Newborn rats wererandomized to breathe room air (A), hypoxia 2 hours +hyperoxia 2 hours (HH) or hypoxia 2 hours + air (HA).We evaluated pulmonary VEGF in rats at 4 days of life byinmuno-histochemistry (sc-152, Santa Cruz) and mRNAVEGF by RT-PCR. The VEGF inmuno-staining and themRNA VEGF were quantified in the pulmonary paren-chyma with ImageJ software. Morphometric assessmentwas done on coded slides with 200x magnification and aeye piece with a sample grid pattern. Differences betweenthe groups were determined by one way ANOVA (p< 0.05).Results are shown in Table 1. Conclusions: Prenatal dexamethasone and betametha-sone have different actions on pulmonary VEGF expressionwith repercussion in the alveolarization. Antenatal dexa-methasone was associated with a significantly lower expres-sion of pulmonary VEGF with a correlation in the decrease ofthe alveolarization, when compared with betamethasone.