Background: Nonsteroidal anti-inflammatory drugs, such as selective phosphodiesterase type 4 (PDE4) inhibitors have potential anti-inflammatory and respiratory smooth muscle relaxation effects. This study aimed to investigate the pathophysiological effects of an intravenous PDE4 inhibitor (rolipram) and surfactant lavage (SL) in a newborn piglet model of meconium aspiration syndrome (MAS).
Methods: MAS was induced in 25 newborn piglets, which were randomly divided into control and four SL treatment groups administered with different doses of intravenous rolipram (0, 0.1, 0.5, and 1 mg/kg). Cardiopulmonary variables were monitored and recorded. The experimental time was 4 hours. Serial blood was drawn for blood gas and biomarker analyses. Lung tissue was examined for histological analysis.
Results: All SL-treated groups revealed improved oxygenation during the 4-hour experiments and had significantly lower peak inspiratory pressure levels than the control group at the end of experiments. All SL plus rolipram-treated groups exhibited significantly higher lung compliance than the control group. However, the animals receiving high-dose (0.5 and 1.0 mg/kg) rolipram demonstrated significantly elevated heart rates. Lung histology of the nondependent sites revealed significantly lower lung injury scores in all SL-treated groups compared with that in the control group, but there were no differences among the rolipram-treated groups.
Conclusions: In addition to SL, intravenous PDE4 inhibitors may further improve lung compliance in treating MAS; however, it is necessary to consider cardiovascular adverse effects, primarily tachycardia. Further investigations are required before the clinical application of intravenous PDE4 inhibitor as an anti-inflammatory agent to treat severe MAS.
Keywords: inflammation; meconium aspiration syndrome; neonate; phosphodiesterase inhibitor; piglet; surfactant lavage.
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