Cigarette smoke induced pathology of the rat respiratory tract: a comparison of the effects of the particulate and vapour phases.

Changes in the rat respiratory tract produced by a 12-week exposure to the particulate or vapour phases of cigarette smoke are described and compared with the changes produced by combined exposure to both phases. The most extensive changge in the upper respiratory tract was a pronounced squamous metaplasia of the laryngeal epithelium, along with extensive deciliation and squame cell production. In the lung, smoke exposure produced marked increase in the numbers of bronchial goblet cells and intra-alveolar brown-gold macrophages. None of the above changes could be directly attributed to exposure to vapour phase alone, and in many cases the lesions produced by whole smoke and by carbon filtered smoke were directly comparable. For lesions to occur in some ciliated areas of the tract both phases of the smoke were required.