In vitro airway responses to methacholine challenge following intermittent neonatal CPAP in mice (870.5)

Abstract

Although continuous positive airway pressure (CPAP) is commonly used in the care of pre‐term infants, its long‐term effects on airway reactivity are largely unknown. In the current study, we investigated whether neonatal CPAP leads to long‐term changes in airway responses to methacholine using the in vitro mouse lung slice preparation. We hypothesized that CPAP treatment during the first week of life would result in a long‐term decrease in airway responsiveness to methacholine. Neonatal mice were exposed to CPAP (6cm H2O) for 3 hours per day for the first 7 postnatal days. Control animals experienced the same conditions as experimental animals only with no CPAP. On days 7 and 21 (2 weeks after CPAP), precision cut lung slices were harvested, and airway responses to increasing doses of methacholine (0.25µM‐8µM) were examined. Contrary to our hypothesis, at both P7 and P21, airways from CPAP exposed mice displayed increased airway reactivity to methacholine challenge when compared to airways from age‐matched control mice. We concluded that CPAP treatment during the early neonatal period may lead to a long‐term increase in airway reactivity.