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Repetitive prenatal glucocorticoid therapy reduces oxidative stress in the lungs of preterm lambs

Repetitive prenatal glucocorticoid therapy reduces oxidative stress in the lungs of preterm lambs Abstract Repetitive courses of maternal prenatal glucocorticoids are often used in high-risk pregnancies with threatening preterm labor to induce lung maturation, but the effects on the cellular oxidant-antioxidant balance in the fetal lung have not been evaluated. We investigated the effect of repetitive treatment with glucocorticoids, beginning early in gestation, on oxidative stress in the preterm ovine lung. Pregnant ewes were randomized to receive one, two, three, or four doses of 0.5 mg/kg betamethasone or saline placebo at 7-day intervals on 104, 111, 118, and 124 days gestation ( n = 11 for each group). All lambs were delivered preterm at 125 days gestation, and lung tissue was assayed for antioxidant enzymes, lipid hydroperoxides, and carbonyl proteins. Lung manganese superoxide dismutase, catalase, and glutathione peroxidase activity increased after 1 dose of betamethasone given at 104 days gestation, whereas copper-zinc superoxide dismutase activity increased after 2 doses given at 104 and 111 days gestation. The activity of all four antioxidant enzymes further increased with additional doses and was maximal after four doses of betamethasone. Lung lipid hydroperoxide levels and carbonyl protein content decreased stepwise after each dose of betamethasone and were lowest after four doses. Repetitive prenatal glucocorticoid therapy increases antioxidant enzyme activity and reduces oxidative stress in the lungs of preterm lambs, and these effects begin early in gestation and persist for 2–3 wk. superoxide dismutase catalase glutathione peroxidase lipid peroxidation carbonyl proteins Footnotes Address for reprint requests: F. J. Walther, Harbor—UCLA REI, 1124 W. Carson St., RB-1, Torrance, CA 90502 (E-mail: fwalther@ucla.edu ). This work was supported by National Heart, Lung, and Blood Institute Grant HL-55534 and National Institute of Child Health and Human Development Grant HD-20618. Copyright © 1998 the American Physiological Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Applied Physiology The American Physiological Society

Repetitive prenatal glucocorticoid therapy reduces oxidative stress in the lungs of preterm lambs

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Publisher
The American Physiological Society
Copyright
Copyright © 2011 the American Physiological Society
ISSN
8750-7587
eISSN
1522-1601
Publisher site
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Abstract

Abstract Repetitive courses of maternal prenatal glucocorticoids are often used in high-risk pregnancies with threatening preterm labor to induce lung maturation, but the effects on the cellular oxidant-antioxidant balance in the fetal lung have not been evaluated. We investigated the effect of repetitive treatment with glucocorticoids, beginning early in gestation, on oxidative stress in the preterm ovine lung. Pregnant ewes were randomized to receive one, two, three, or four doses of 0.5 mg/kg betamethasone or saline placebo at 7-day intervals on 104, 111, 118, and 124 days gestation ( n = 11 for each group). All lambs were delivered preterm at 125 days gestation, and lung tissue was assayed for antioxidant enzymes, lipid hydroperoxides, and carbonyl proteins. Lung manganese superoxide dismutase, catalase, and glutathione peroxidase activity increased after 1 dose of betamethasone given at 104 days gestation, whereas copper-zinc superoxide dismutase activity increased after 2 doses given at 104 and 111 days gestation. The activity of all four antioxidant enzymes further increased with additional doses and was maximal after four doses of betamethasone. Lung lipid hydroperoxide levels and carbonyl protein content decreased stepwise after each dose of betamethasone and were lowest after four doses. Repetitive prenatal glucocorticoid therapy increases antioxidant enzyme activity and reduces oxidative stress in the lungs of preterm lambs, and these effects begin early in gestation and persist for 2–3 wk. superoxide dismutase catalase glutathione peroxidase lipid peroxidation carbonyl proteins Footnotes Address for reprint requests: F. J. Walther, Harbor—UCLA REI, 1124 W. Carson St., RB-1, Torrance, CA 90502 (E-mail: fwalther@ucla.edu ). This work was supported by National Heart, Lung, and Blood Institute Grant HL-55534 and National Institute of Child Health and Human Development Grant HD-20618. Copyright © 1998 the American Physiological Society

Journal

Journal of Applied PhysiologyThe American Physiological Society

Published: Jul 1, 1998

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