Abstract
Strain differences of mice in their susceptibility to nitrogen dioxide (NO 2) were examined by measuring the activities of antioxidative protective enzymes, and the amounts of antioxidants and lipid peroxides in lungs. Four strains of mice: ICR, BALB/c, ddy and C57BL/6 were used in this study and their LC 50 values after exposure to NO 2 for 16 hr were: 38, 49, 51 and 64 ppm, respectively (1). Genetic strain differences were observed in the enzyme activities, the antioxidant contents and lipid peroxide contents among these four different strains. The activities of glutathione peroxidase (GP x), glutathione S-transferase, and superoxide dismutase (SOD), and the contents of non-protein sulfhydryls (NPSH), α-tocopherol (α-Toc) and total lipids in lungs of the four strains were related to their LC 50, while TBA reactants in lungs of the four strains were inversely related to their LC 50. After exposure to 20 ppm NO 2 for 16 hr, the activities of the protective enzymes and the contents of NPSH decreased, while the level of α-Toc increased markedly. The activities of GP x, 6-phosphogluconate dehydrogenase, SOD and disulfide reductase, and the contents of NPSH, α-Toc and total lipids were also related to their LC 50. On the other hand, TBA reactants increased higher than those of the control groups and were inversely related to their LC 50. These results suggest that the protective enzymes and the antioxidants are important factors as defence mechanism in lungs to NO 2 and that the intensity of the protective systems in pigmented strains is generally greater than that in albino strains.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call