Vitamin A deficiency and pulmonary oxygen toxicity: morphometric studies in the murine lung.
Vitamin A and its precursor beta-carotene are naturally occurring antioxidants. The effects of diets deficient in beta-carotene and vitamin A on the alveolar-capillary membrane were studied in young adult BALB/C mice before and after exposure to 65% oxygen. One of three diets (standard complete, beta-carotene deficient, or beta-carotene and vitamin A deficient) was fed for a 6-wk period. Mice were then exposed to 65% oxygen for 0, 3, or 6 days, sacrificed, and their lungs examined by electron microscopy using the morphometric techniques of Weibel. The arithmetic and the harmonic mean thicknesses of the alveolar-capillary membrane and its components (epithelium, interstitium, and endothelium) were measured to assess the influences of diet and of duration of exposure to 65% oxygen. Analysis of variance and multiple comparisons of means (Student-Neuman-Keuls statistics) were applied. Diet alone did not significantly affect membrane thickness. However, duration of oxygen exposure increased the thicknesses of both the epithelium and interstitium in the group fed a diet deficient in both beta-carotene and vitamin A as compared to the other two groups although this was only significant for the epithelium. beta-Carotene deficiency alone did not affect the respiratory membrane either before or after oxygen exposure. These results suggest that vitamin A may be an important nutrient in the protection against pulmonary oxygen toxicity.
Cohen-Addad
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N
Department of Pediatrics, New Jersey Medical School, Newark 07103.
Bollinger
R
R
Chou
J
J
Poland
R
R
D000818:Animals; D002338:Carotenoids / Q000172:deficiency*; D003238:Connective Tissue / Q000473:pathology; D004727:Endothelium / Q000473:pathology; D004848:Epithelium / Q000473:pathology; D005260:Female; D008168:Lung / Q000187:drug effects / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000473:pathology; D010100:Oxygen / Q000633:toxicity*; D011446:Prospective Studies; D014802:Vitamin A Deficiency / Q000473:pathology*; D019207:beta Carotene
D019207:beta Carotene; D002338:Carotenoids; D010100:Oxygen