背景:出生相关的脐血流阻塞可能会引起低氧损伤,从而影响出生后器官的适应。使用新生儿剖腹产的猪,我们假设分娩过程中脐带阻塞会对生理过渡和肠道成熟产生负面影响.Further,我们调查了延迟脐带夹闭(DCC)是否可以改善肠道结局,包括对配方诱导的坏死性小肠结肠炎(NEC)样病变的敏感性。
方法:在实验1中,对早产(n=24)和近期(n=29)仔猪进行脐带阻塞(UCO,子宫内5-7分钟),在没有阻塞的情况下运送相应的猪(CON,n=17-22)。实验2评估了接受脐带夹钳(n=30,60s)或脐带挤奶立即切断的早产猪(UCM,n=34)。记录出生后的重要参数,以及配方喂养3天后的一系列肠道参数。
结果:UCO在出生时引起的近期猪呼吸代谢性酸中毒(pH7.16vs.7.32,pCO212.5与9.2kPa,乳酸5.2vs.2.5mmol/L,p<0.05)。在早产猪中,UCO增加了出生后不久的复苏失败和死亡率(88vs.47%,p<0.05)。UCO不影响肠道通透性,运输时间,大分子吸收,六种消化酶,或对NEC样病变的敏感性。在实验2中,DCC改善了新生儿血流动力学(pH7.28vs.7.20,pCO28.9vs.9.9在2小时,p<0.05),对肠道参数没有影响。
结论:UCO和DCC影响新生儿过渡和血流动力学,但不是新生儿肠道适应或对NEC样病变的敏感性。我们的发现表明,未成熟的新生儿肠道对脐带血流量的短暂出生相关变化具有很高的抵抗力。
BACKGROUND: Birth-related obstruction of umbilical blood flow may induce hypoxic insults that affect postnatal organ adaptation. Using newborn cesarean-delivered pigs, we hypothesized that cord obstruction during delivery negatively affects physiological transition and gut maturation. Further, we investigated if delayed cord clamping (DCC) improves gut outcomes, including sensitivity to formula-induced necrotizing enterocolitis (NEC)-like lesions.
METHODS: In experiment 1, preterm (n = 24) and near-term (n = 29) piglets were subjected to umbilical cord obstruction (UCO, 5-7 min in utero), with corresponding pigs delivered without obstruction (CON, n = 17-22). Experiment 2 assessed preterm pigs subjected to delayed cord clamping (n = 30, 60 s) or immediate cord transection with umbilical cord milking (UCM, n = 34). Postnatal vital parameters were recorded, together with a series of gut parameters after 3 days of formula feeding.
RESULTS: UCO induced respiratory-metabolic acidosis in near-term pigs at birth (pH 7.16 vs. 7.32, pCO2 12.5 vs. 9.2 kPa, lactate 5.2 vs. 2.5 mmol/L, p < 0.05). In preterm pigs, UCO increased failure of resuscitation and mortality shortly after birth (88 vs. 47%, p < 0.05). UCO did not affect gut permeability, transit time, macromolecule absorption, six digestive enzymes, or sensitivity to NEC-like lesions. In experiment 2, DCC improved neonatal hemodynamics (pH 7.28 vs. 7.20, pCO2 8.9 vs. 9.9 at 2 h, p < 0.05), with no effects on gut parameters.
CONCLUSIONS: UCO and DCC affect neonatal transition and hemodynamics, but not neonatal gut adaptation or sensitivity to NEC-like lesions. Our findings suggest that the immature newborn gut is highly resilient to transient birth-related changes in cord blood flow.