Betamethasone worsens chorioamnionitis-related lung development impairment in rabbits

Although chorioamnionitis and glucocorticoids (GC) are both known to have potential adverse effects on alveolar development, the use of GC is generalized because of their demonstrated benefits in premature newborns. The objective of this study was to analyze the cumulative effects of GC and chorioamnionitis on lung development and infectious process. In a model of ESCHERICHIA COLI chorioamnionitis controlled by antibiotics, pregnant rabbits were randomized among five groups: (1) E. COLI infection alone, (2) infection plus one betamethasone injection (0.1 mg.kg(-1)), (3) infection plus two betamethasone injections, (4) betamethasone alone, (5) control. Lung morphometric analysis, bronchoalveolar lavage, and bacteriologic tissue cultures were performed after spontaneous delivery. In the context of chorioamnionitis, one betamethasone treatment significantly decreased birth weight and lung volume versus controls (30 ± 1.40 versus 52.40 ± 2.54 g, and 1.92 ± 0.67 versus 2.15 ± 0.74 cm(3), respectively, p < 0.05). Two betamethasone treatments significantly decreased specific alveolar area (279.8 ± 46 cm(2)/100 g versus 510.90 ± 54.1 cm(2)/100 g), specific interstitium volume (0.98 ± 0.09 cm(3)/100 g versus 1.78 ± 0.16 cm(3)/100 g), and specific elastin fiber length (57.4 ± 10.5 versus 183.6 ± 8.1 cm/100 g). These results suggest that glucocorticoid treatment might represent an additional risk factor for lung development in the instance of prenatal infection.