Quinlivan J A, Beazley L D, Braekevelt C R, Evans S F, Newnham J P, Dunlop S A
University Department of Obstetrics and Gynecology, University of Western Australia, Australia.
J Perinat Med. 2001;29(2):112-27. doi: 10.1515/JPM.2001.015.
Recent studies in sheep have shown that repeated maternal injections of betamethasone are associated with adverse effects within the nervous system. Repeated fetal injections of betamethasone achieve serial improvements in preterm lung function in sheep and are a possible alternative to repeated maternal therapy. We have evaluated the effect of repeated fetal administration of betamethasone on nervous system maturation in an ovine model.
Date-mated ewes (n = 48) were randomized to receive ultrasound-guided fetal injections of betamethasone or saline between days 104 to 124 of gestation and were delivered by cesarean section on day 125 or 145 (term = 150). Optic and sciatic nerves were prepared for light and electronmicroscopy. Eye diameters were measured and transverse sections of retinae were evaluated. Data were analyzed using a mixed model analysis of variance.
Repeated fetal administration of corticosteroid did not significantly affect optic nerve myelination but resulted in significant delays in sciatic axonal growth (p < 0.02) and retinal maturation (p < 0.04). The process of performing repeated fetal injections also significantly affected some retinal parameters.
Repeated fetal administration of betamethasone alters some aspects of nervous system maturation in sheep. It is premature to plan trials of repeated fetal corticosteroid therapy in humans.
最近在绵羊身上的研究表明，母体反复注射倍他米松与神经系统的不良反应有关。反复给胎儿注射倍他米松可使绵羊早产肺功能得到一系列改善，这可能是反复母体治疗的一种替代方法。我们评估了在绵羊模型中反复给胎儿注射倍他米松对神经系统成熟的影响。
将已配种的母羊（n = 48）随机分为两组，在妊娠第104至124天期间接受超声引导下给胎儿注射倍他米松或生理盐水，并在第125天或145天（足月为150天）进行剖宫产。准备视神经和坐骨神经用于光学和电子显微镜检查。测量眼径并评估视网膜横切面。使用方差混合模型分析数据。
反复给胎儿注射皮质类固醇对视神经髓鞘形成没有显著影响，但导致坐骨神经轴突生长显著延迟（p < 0.02）和视网膜成熟显著延迟（p < 0.04）。进行反复胎儿注射的过程也显著影响了一些视网膜参数。
反复给胎儿注射倍他米松会改变绵羊神经系统成熟的某些方面。计划在人类中进行反复胎儿皮质类固醇治疗试验还为时过早。
