REGENERATION OF OLFACTORY MUCOSA IN MICE AFTER INHALATION EXPOSURE TOPERCHLOROETHYLENE

An experimental group of 20 male pure-bred mice was exposed to perchlo roethylene gas at 300 ppm for 6 h daily for 5 days. Histopathological study of the nasal mucosa, particularly the olfactory mucosa, was perf ormed sequentially 2 weeks to 3 months after exposure, to clarify the process of regeneration. The tissue damage due to perchloroethylene ga s was more persistent in the nasal mucosa of the olfactory region than in the respiratory region. Two weeks after exposure, ciliated epithel ial cells, as well as normal pseudostratified nonciliated columnar epi thelium, began to appear in the area previously covered by olfactory e pithelium and remained for up to 3 months after exposure. A basement m embrane was present under the ciliated epithelium, suggesting a possib le persistence of basal cells. The olfactory epithelium may thus be re placed by ciliated epithelium. The lamina propria of the olfactory muc osa, however, lost its normal structure with atrophy of the olfactory nerves and Bowman's glands.