Clinical and pathological effects of cigarette smoke exposure in beagle dogs.

To compare the clinical and pathological effects of high and low nicotine cigarette smoke 12 young adult male beagles were separated into four equal groups and exposed to smoke from high (4.6 mg) or low (1.4 mg) nicotine cigarettes, administered in six or 12 cigarettes per day. Two control groups, sham-exposed and nontracheostomized, consisted of three dogs each. The dogs were exposed seven days per week for five months. Tracheobronchitis developed in smoke-exposed dogs; gross lesions were generally confined to the lungs and tracheobronchial lymph nodes. Histopathological changes were found in all smoke-exposed dogs, with slightly more severe or extensive lesions in the dogs exposed to 12 cigarettes per day. The incidence and severity of rhinitis, turbinate basal epithelial cell hyperplasia, and squamous metaplasia were increased among dogs in the high nicotine cigarette groups.