Chronic zinc deficiency induces an antioxidant adaptive response in rat lung

Few studies are available about the role of dietary zinc (Zn) in respiratory diseases. Adult male rats were divided into 2 groups and fed respectively a moderate Zn-deficient diet and a Zn-adequate control diet. In lung tissue at 2 months, thiobarbituric acid-reactive species (TBARS), total glutathione, glutathione disulfide, protein carbonyls, metallothionein, and the activities of glutathione peroxidase (GPx), catalase, CuZn-superoxide dismutase (CuZnSOD) and glucose-6-phosphate dehydrogenase (G-6-PDH) were increased, but protein thiols decreased. In lung tissue at 4 months, TBARS, metallothionein, and the activities of CuZnSOD, Mn-superoxide dismutase (MnSOD) increased. The activities GPx, catalase, G-6-PDH were lower than control group. The changes were accompanied by histological alterations in Zn-deficient lung. The results provide evidence of the pro-oxidative effects of Zn-deficiency in lung, and suggest that the time of treatment play a key role in determining lung susceptibility to oxidative stress.