Influences of Tobacco Smoke and Vitamin E Depletion on the Distal Lung of Weanling Rats

Abstract

Tobacco smoke is associated with pulmonary emphysema via elastase—antielastase and oxidant—antioxidant imbalance. This study addressed the tobacco smoke-induced changes in the lungs of weanling rats with vitamin E depletion. Three-week-old Wistar rats fed on vitamin E-depleted or normal diet were intermittently exposed to tobacco smoke by Hamburg II machines for 4 weeks. Tobacco smoke significantly suppressed body weight increases, particularly in the vitamin E-depleted group. In the normal diet group, tobacco smoke induced emphysematous changes with significant increases in the mean linear intercept (L_m) and the destructive index (DI), which was supported by an increase in elastase-like activity and a decrease in elastase inhibitory capacity (EIC) in bronchoalveolar lavage (BAL) fluid. Vitamin E depletion alone altered neither L_m nor DI. In tobacco-exposed animals in addition to vitamin E depletion, elastase-like activity, EIC in BAL fluid and DI were comparable to that in tobacco-exposed animals on a normal diet. However, L_m was markedly decreased with thickened epithelium and shrunk alveolar space. These results suggest that vitamin E depletion, when linked to tobacco exposure, might induce impaired lung development in the weanling rats, which is different from the emphysematous changes.

Key Words:

• elastase
• pulmonary emphysema
• tobacco smoke
• vitamin E