Lung maneuvers of large amplitudes for probing physiological alterations in mouse models of asthma.

backgroundMouse models are commonly used to study asthma. Oscillometry, a technique using small-amplitude maneuvers, is often used to probe physiological lung alterations in mice. However, the changes in oscillometric readouts in mouse models of asthma are typically subtle, implying the need for using large sample sizes. Herein, lung maneuvers of different amplitudes were used to compare their sensitivity in detecting physiological alterations in mouse models of asthma.

methodsFemale BALB/c mice were exposed to saline or house dust mite (HDM) intranasally to induce experimental asthma. They were exposed either thrice per week for 5 weeks (long protocol) or for 10 consecutive days (short protocol). The presence of physiological alterations was tested using lung maneuvers of small amplitudes (oscillometry), intermediate amplitudes (the partial pressure-volume maneuver), and large amplitudes (full-range pressure-volume maneuvers) to quantify equivalent readouts, such as compliance, within different ranges of lung volumes.

resultsThe differences between saline- and HDM-exposed mice increase with the maneuver amplitude. In the long protocol, for example, the decreased compliance caused by HDM was on average 3.2% (p = 0.39), 6.6% (p = 0.060), and 37.7% (p < 0.0001) when tested with maneuvers of small, intermediate, and large amplitudes, respectively. In the short protocol, these values were 3.1% (p = 0.35), 5.5% (p = 0.16), and 35.3% (p < 0.0001), respectively.

conclusionLung maneuvers of large amplitudes can detect physiological alterations with a greater sensitivity in mouse models of asthma. These results are particularly useful for scientists using mouse models to test countermeasures, such as drugs, in asthma.