Long-term NO2 exposure of mice in the presence and absence of vitamin E. I. Effect on body weights and lipofuscin pigments.

Mice on diets deficient in vitamin E, normal diets, diets with high supplements of vitamin E, and diets supplemented with N, N'-diphenyl-p-phenylenediamine (DPPD) were continuously exposed to 0.5 ppm or to 1.0 ppm nitrogen dioxide (NO2) or to filtered room air from weaning to 18 months of age. The effects of NO2 exposure on body weights, tissue weights, survival rates, and tissue organic solvent soluble lipofuscin (age) pigment concentrations were examined. Vitamin E deficiency resulted in lower body weights by 18 months of age; exposure to NO2 further increased this weight loss. With the exception of the kidney, tissue weights were not affected by NO2 exposure. Mice exposed to NO2 had lower survival rates than unexposed control animals. Tissue organic solvent soluble lipofuscin pigment (LFP) concentrations in the uterus, lung, spleen, kidney, liver, brain, and heart were not afffected by NO2 exposure. Only in the liver did vitamin E deficiency lead to an increase in LFP concentration; it did not occur in any of the other tissues examined.