Goblet cell metaplasia in rat lungs after chronic exposure to particles

After long-term inhalation of Printex 90 and titanium dioxide, goblet cell metaplasias occured in the peripheral lung tissue of 11/1700 female SPF Wistar rats. The majority of goblet cell metaplasias was seen at the bronchiolo-alveolar junction as round, mucus-filled nodules with a diameter of 1 - 20 mm. Their periphery consisted of a single layer of well differentiated columnar goblet cells. In central mucus-filled areas, alveolar epithelium and septae were often markedly reduced. Mucus and goblet cells stained positive with PAS and Alcian blue, both at pH 2.5 and 1. Goblet cell metaplasias have been reported in pulmonary airways of man and hamsters, but have rarely been described in the peripheral lung tissue of rats.