Reversible Damage of Rat Upper Respiratory Tract Caused by Cigarette Smoke

Adult rats (Sprague-Dawley) were exposed to whole cigarette smoke for different periods of time and then killed at various stages of recovery. Maxillary sinuses and glands were prepared for histological examination and studied with light microscopy. During experimental period, maxillary epithelium lost columnar ciliated cells and hypertrophied. Acute inflammatory reaction occurred in submucosa. While entire maxillary gland underwent modification of morphological properties, individual goblet cells containing acid mucosubstances differentiated within new maxillary epithelium. Extravascular lymphocytes, polymorphonuclear leukocytes, and macrophages migrated in great numbers from submucosa to lumen of sinus by way of epithelium. Some migrating cells invaded lumina of excretory ducts. Maxillary sinus contained a massive amount of pus. Microabscesses were scattered throughout epithelium of animals exposed to smoke for a longer time. In spite of morphological changes initiated by experiment, normal structure around maxillary sinus reestablished quickly after cessation of experiment and throughout recovery.