Role of selenium in neonatal lung development

Experiments were conducted to assess the role of dietary selenium (Se) in development of neonatal lungs under normoxia and hyperoxia. Lung development was assessed by measuring certain parameters of functional and structural development, including pulmonary phospholipids and histomorphometry. Lung lesions due to hyperoxia were assessed by histopathological examination and by histomorphometry. Female Sprague Dawley rats were bred and fed a Se-deficient (0.03-0.04 ppm) diet or a Se-adequate (0.5 ppm) diet during pregnancy and lactation. When neonatal pups were exposed to high O$\sb2$ concentrations ($>$95%) for 4 days from d 2-6 of age, pulmonary Se-dependent glutathione peroxidase (SeGPx) activity was increased in both Se-deficient and Se-adequate pups, but only Se-adequate pups were protected from O$\sb2$-induced lung lesions. Se inadequacy resulted in an elevated incidence and severity of pulmonary interstitial inflammation and septal attenuation and a decrease in lung weights. When Se deficient neonatal pups were repleted via dam's milk by selenite supplementation to dams, Se-repleted pups had significantly greater lung volume and pulmonary internal surface area than Se-deficient pups. Se-repleted pups were also partially protected from hyperoxic lung lesions. Tissue concentrations of Se and SeGPx activity in pup plasma and liver were significantly elevated by Se repletion. In contrast, the glutathione concentration and SeGPx activity in pup lungs were increased only by O$\sb2$ exposure, regardless of Se nutriture. Oral supplementation of selenite to rat pups (3.2 ng Se/g BW/d) was not as effective as Se repletion via the milk in enhancing lung development and protecting lungs from hyperoxia. In a normal air environment, pulmonary disaturated phosphatidylcholine/total phosphatidylcholine ratio was significantly decreased in 16-d-old Se-deficient rat pups in comparison to Se-adequate rat pups, implying that Se deficiency results in less functional pulmonary surfactant, leading to increased alveolar surface tension. These data indicate that Se has an important role in neonatal lung development, a role that is even more pronounced under conditions of hyperoxia. However, the exact role of Se in protecting the neonatal lung cannot be attributed entirely to its effects on pulmonary SeGPx activity or pulmonary glutathione.U of I OnlyETDs are only available to UIUC Users without author permissio