Respiratory tract lesions induced in rabbits by short-term exposure to N-hexane.

New Zealand rabbits were exposed in inhalation chambers to 3,000 ppm of n-hexane 8h/d for 8 d, and the acute respiratory effects were studied by light and electron microscopy. Animals intoxicated showed morphological changes in the lung parenchyma characterized by centriacinar emphysema and scattered micro haemorrhages. Lung damage was most severe at the transition zone from terminal bronchiole to alveolar ducts. This centriacinar lesion consisted to degenerative and necrotic phenomena in bronchiolar epithelium with cellular desquamation, increased number of macrophages within proximal alveoli of alveolar ducts, increased number and size of lamellar bodies in alveolar type II cells, changes in the vascular endothelium. Focal subpleural atelectasis, alveolar and interstitial oedema were also found. The segmental distribution of the pulmonary lesions were confirmed by transmission electron microscopy.