Measurement of AHR
Mice were anesthetized by intraperitoneal injection of xylazine (12
mg/kg) and pentobarbital (70 mg/kg) at 3, 7, and 10 days post-infection.
After anesthetization, mice were cannulated and connected to an animal
ventilator (flexiVent®, SCIREQ, Montreal, QC, Canada).
The mice inhaled aerosolized phosphate-buffered saline or 3, 6, 12, 24,
or 48 mg/mL methacholine in phosphate-buffered saline. We measured the
following parameters: resistance of the respiratory system
(Rrs) and tissue damping (G); Rrs and G
reflect the resistance of the central and peripheral airways,
respectively17, 18. These parameters were measured at
frequent intervals of 10–15 seconds 12 times following activation of
the nebulizer.