INFLUENCES OF TOBACCO-SMOKE AND VITAMIN-E DEPLETION ON THE DISTAL LUNG OF WEANLING RATS

Tobacco smoke is associated with pulmonary emphysema via elastase-anti elastase and oxidant-antioxidant imbalance. This study addressed the t obacco smoke-induced changes in the lungs of weanling rats with vitami n E depletion. Three-week-old Wistar rats fed on vitamin E-depleted or normal diet were intermittently exposed to tobacco smoke by Hamburg I I machines for 4 weeks. Tobacco smoke significantly suppressed body we ight increases, particularly in the vitamin E-depleted group. In the n ormal diet group, tobacco smoke induced emphysematous changes with sig nificant increases in the mean linear intercept (L(m)) and the destruc tive index (DI), which was supported by an increase in elastase-like a ctivity and a decrease in elastase inhibitory capacity (EIC) in bronch oalveolar lavage (BAL) fluid. Vitamin E depletion alone altered neithe r L(m) nor DI. In tobacco-exposed animals in addition to vitamin E dep letion, elastase-like activity, EIC in BAL fluid and DI were comparabl e to that in tobacco-exposed animals on a normal diet. However, L(m) w as markedly decreased with thickened epithelium and shrunk alveolar sp ace. These results suggest that vitamin E depletion, when linked to to bacco exposure, might induce impaired lung development in the weanling rats, which is different from the emphysematous changes.