Ikegami M, Jobe A H, Newnham J, Polk D H, Willet K E, Sly P
Perinatal Research Laboratories, Harbor-UCLA Medical Center, Torrance, USA.
Am J Respir Crit Care Med. 1997 Jul;156(1):178-84. doi: 10.1164/ajrccm.156.1.9612036.
We evaluated the effects of multiple fetal exposures to glucocorticoids on postnatal lung function and growth. Ewes were randomized to receive 1 to 4 doses of 0.5 mg/kg betamethasone or saline placebo at 7 d intervals from 104 d to 118 d and at 124 d gestation. All lambs were delivered preterm at 125 d gestation, and postnatal lung function was evaluated. There were sequential improvements in compliance, ventilation efficiency, and lung volumes for two, three, and four doses of betamethasone. The maximal effect was a 150% increase in compliance and a 4-fold increase in lung volume after fetal exposure to four doses of betamethasone. However, birth weights decreased (15% after one dose, 19% after two doses, and 27% after three and four doses). There were no changes in lung to body weight ratios, lung dry to wet weight ratios, lung protein to body weight ratios, or lung hyaluronan content. Prenatal glucocorticoid exposure also altered postnatal cortisol, thyroid, and catecholamine plasma levels. Repetitive 7-d interval exposures of fetal lambs to glucocorticoids progressively enhanced postnatal lung function and resulted in growth and endocrine abnormalities.
我们评估了多次胎儿暴露于糖皮质激素对出生后肺功能和生长的影响。将母羊随机分为两组，从妊娠104天至118天以及妊娠124天时，每隔7天接受1至4剂0.5mg/kg倍他米松或生理盐水安慰剂。所有羔羊均在妊娠125天时早产，并对出生后的肺功能进行评估。接受两剂、三剂和四剂倍他米松后，顺应性、通气效率和肺容量依次得到改善。最大效果是胎儿暴露于四剂倍他米松后，顺应性增加150%，肺容量增加4倍。然而，出生体重下降（一剂后下降15%，两剂后下降19%，三剂和四剂后下降27%）。肺与体重比、肺干重与湿重比、肺蛋白与体重比或肺透明质酸含量均无变化。产前糖皮质激素暴露还改变了出生后的皮质醇、甲状腺和儿茶酚胺血浆水平。胎儿羔羊每隔7天重复暴露于糖皮质激素会逐渐增强出生后的肺功能，并导致生长和内分泌异常。
