Airway and tissue mechanics in a murine model of asthma: alveolar capsule vs. forced oscillations.
To better address the functional consequences of inflammation on bronchial responsiveness, we studied two groups of BALB/c mice: a nonimmunized control group (n = 8) and a group immunized and challenged with inhaled ovalbumin (n = 8). An alveolar capsule (AC) measured airway resistance (Raw(AC)) and lung elastance (EL). A forced oscillation (FO) technique independently estimated airway resistance (Raw(FO)) and a parameter H(ti) related to tissue elastance. Ovalbumin-immunized and -challenged mice had increased numbers of eosinophils in bronchoalveolar lavage and increased responsiveness to methacholine (MCh). Corresponding parameters from the AC and FO techniques were correlated: Raw(AC) vs. Raw(FO) (r = 0.76) and EL vs. H(ti) (r = 0.88, P < 0.0001 in all cases). AC and FO techniques showed significant increases in tissue elastance in response to MCh but no significant increases in airway resistance. These results demonstrated that the AC and FO techniques yield essentially equivalent results in mice, even when the lung is inhomogeneous, and that the bronchoconstrictive responses to MCh and inflammation in mice are predominantly located in the lung periphery.
Tomioka
Shinichiro
S
Vermont Lung Center, Fletcher Allen Health Care, Department of Medicine, University of Vermont, Burlington 05405-0075, USA.
Bates
Jason H T
JH
Irvin
Charles G
CG
D000280:Administration, Inhalation; D000403:Airway Resistance / Q000502:physiology; D000465:Algorithms; D000818:Animals; D001249:Asthma / Q000503:physiopathology*; D001986:Bronchial Spasm / Q000139:chemically induced / Q000503:physiopathology; D001992:Bronchoalveolar Lavage Fluid; D016085:Bronchoconstrictor Agents; D004305:Dose-Response Relationship, Drug; D004548:Elasticity; D005260:Female; D007249:Inflammation / Q000503:physiopathology; D016210:Methacholine Chloride; D051379:Mice; D008807:Mice, Inbred BALB C; D011650:Pulmonary Alveoli / Q000503:physiopathology*; D012121:Respiration, Artificial; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000502:physiology*; D012137:Respiratory System / Q000503:physiopathology*
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride