Effects of Sulfur Dioxide on the Nasal Mucosa of Mice

Mice from a defined-flora colony (DF) which were free of disease, and conventional mice (CO) which had mild upper-respiratory tract disease were exposed to 10 ppm of sulfur dioxide for periods of up to 72 hours to compare (a) the histopathothologic effects in the nasal cavity with those in the lungs within each group, and (b) the differences in response to SO2 between DF and CO mice. The earliest lesions due to SO2 were observed in the nasomaxillary turbinates after 24 hours of exposure and consisted of edema, necrosis, and desquamation of the respiratory and olfactory epithelium. There was far more severe injury in the nasomaxillary turbinates than in the remainder of the respiratory tract. The CO mice with mild upper-respiratory tract infection had more severe lesions than the DF mice.