Dynamic airway constriction in rats: heterogeneity and response to deep inspiration.

Dynamic airway constriction in rats: heterogeneity and response to deep inspiration. Am J Physiol Lung Cell Mol Physiol. 2019 Apr 24;: Authors: Phung TN, Sinclair SE, Makena PS, Molthen RC, Waters CM Abstract Airway narrowing due to hyper-responsiveness severely limits gas exchange in patients with asthma. Imaging studies in humans and animals have previously shown that bronchoconstriction causes patchy patterns of ventilation defects throughout the lungs, and several computational models have predicted that these regions are due to constriction of smaller airways. However, these imaging approaches are often limited in their ability to capture dynamic changes in small airways, and the patterns of constriction are heterogeneous. To directly investigate regional variations in airway narrowing and the response to deep inspirations (DI's), we utilized tantalum dust and microfocal X-ray imaging of rat lungs to obtain dynamic images of airways in an intact animal model. Airway resistance was simultaneously measured using the flexiVent system. Custom software was used to track changes in airway diameters up to 19 generations (~0.3 mm to 3 mm in diameter). Changes in diameter during bronchoconstriction were then measured in response to methacholine (MCh) challenge. In contrast with the model predictions, we observed significantly greater percent constriction in larger airways in response to MCh challenge. Although there was a dose-dependent ...
Source: Am J Physiol Lung Ce... - Category: Respiratory Medicine Authors: Tags: Am J Physiol Lung Cell Mol Physiol Source Type: research