nitrogen-dioxide and Vitamin-A-Deficiency

The effect of dietary vitamin A and NO2 exposure on the hamster lung was evaluated by histopathology, electron microscopy, and thymidine uptake studies. Hamsters were maintained on deficient (0 micrograms), adequate (100 micrograms), and high (200 micrograms) dose levels of vitamin A while being exposed repeatedly to 10 ppm of NO2 for 5 hours once a week over an 8-week period. Hamsters of the deficient group exhibited clinical and morphologic changes characteristic of vitamin A deficiency. Animals maintained on adequate and high dose levels of vitamin A were not affected by vitamin A deficiency. Hypertrophy and hyperplasia of the epithelial cells of the terminal bronchiolar alveolar region of lungs of adequately and highly dosed animals were greater than those observed in the deficient animals, when NO2 exposure was given. However, the extent of the lesions observed in all three groups was less than that seen in normal hamsters given a single, 5-hour NO2 exposure. Ultrastructural changes observed in vitamin A-deficient hamsters exposed to NO2 were hypertrophy and hyperplasia of bronchiolar epithelial cells, diffuse loss of cilia, membrane damage, and mitochondrial damage manifested by calcium deposition. Tritiated thymidine uptake studies of lungs of animals exposed repeatedly revealed a rather erratic cell renewal pattern following NO2 exposure in comparison to the group of animals exposed singly.

Topics: Animals; Blood Cell Count; Body Weight; Cricetinae; Diet; Dose-Response Relationship, Drug; Environmental Exposure; Female; Hypertrophy; Lung; Nitrogen Dioxide; Organ Specificity; Pregnancy; Vitamin A; Vitamin A Deficiency

Hamsters exposed to 10 ppm NO2 for 5 hr once a week for 4 weeks while undergoing acute vitamin A deficiency showed much reduced epithelial cell regeneration in the terminal bronchioles. Quantitative analysis done by autoradiography and scintillation counting from lung tissues indicates much reduced cell kinetics occurring in terminal bronchiolar alveolar region. Alveolar necrosis was often observed and no type II cell reversion occurred. Virus particles were found within the alveolar epithelial plasma membrane.

Topics: Animals; Body Weight; Cricetinae; DNA; Nitrogen Dioxide; Pulmonary Alveoli; Viruses; Vitamin A Deficiency