Mucus hypersecretion and viscoelasticity changes in cigarette-smoking dogs.

Chronic cigarette smoke exposure is well known to cause mucus hypersecretion in experimental animals, but the alterations in mucus rheology have not been described. We studied mucus hypersecretion and viscoelasticity changes in nine tracheostomized beagle dogs exposed to cigarette smoke. The dogs were trained to stand quietly in a harness, and smoke was delivered via a cuffed tracheostomy tube.

Hyporesponsiveness to aerosolized but not to infused methacholine in cigarette-smoking dogs.

Seven beagles were exposed via a tracheostomy to smoke from 10 cigarettes/day, 5 days/wk for 10 months; 2 other dogs were exposed for 6 months only. Four dogs served as sham-exposed control animals. Mucus was collected 2 times/wk prior to and during the exposure period by resting a cytology brush on the lower trachea for 2 to 5 min.