Protective effects of dietary -tocopherol in rats exposed to toxic levels of ozone and nitrogen dioxide

The effect of dietary α-tocopherol at various levels, especially in the range 0–45 mg/kg, on the acute toxicity of O₃ and NO₂ to rats was studied. The highest level of α-tocopherol was 1500 mg/kg of diet in combination with ascorbic acid, dl-methionine and butylated hydroxytoluene; the level of O₃ ranged from 0.7 to 16 ppm and NO₂ from 20 to 25 ppm; and various exposure periods were used. α-Tocopherol alone and in combination with the other antioxidants exerted a protective effect in rats exposed to O₃ and NO₂ as measured by acute toxicity and animal weight change. During 1 ppm O₃ exposure voluntary activity decreased, while at lower levels of O₃ (0.7–0.8 ppm) α-tocopherol protection against lipid peroxidation in the lung, as measured by endogenous lung thiobarbituric acid reactants, was a reciprocal function of the logarithm of dietary α-tocopherol. Extracts of lung tissue from animals exposed to O₃ and O₂ showed no increase in fluorescent products associated with lipid peroxidation.