Study on mechanisms for inducing periventricular leucomalacia prior to delivery usig extrauterine incubation system of a goat fetus.

为了探讨分娩前诱发脑室周围白质软化症（PVL）的机制，我们尝试在山羊胎儿上使用子宫外孵育系统。据推测，由短暂脐静脉压迫引起的早产儿脑连续缺血和再灌注可能是诱导PVL的病因。11只胎龄约125天（足月145天）的山羊胎儿使用子宫外孵育系统与动静脉体外膜肺氧合（A-V ECMO）进行孵育。与脐静脉相连的导管完全闭塞（5例完全闭塞）或部分闭塞（6例75%闭塞）15秒后解除闭塞。在接下来的45秒内，通过导管输注在闭塞期间储存在注射器中的血液的总体积。该程序以5分钟的间隔连续重复6次。术后宫外孕发生率为100%， 关于我们 持续4天。然后处死山羊胎儿，并对脑组织进行组织病理学检查以确定PVL病变的存在。脐静脉导管阻断期间，胎心率、胎血压、颈动脉血流量及皮层脑电图振幅均明显下降。然而，这些患者在闭塞缓解后很快恢复。术前和术后血气检查无明显差异。7/11胎羊侧脑室周围深部白色物质内可见凝固性坏死灶，是PVL的原发灶。提示脐静脉持续压迫引起早产儿脑缺血再灌注可能在PVL的发生中起重要作用。同时，该体外孵育系统可为研究胎儿病理学提供一种实验动物模型。少

To investigate the mechanisms for inducing periventricular leucomalacia (PVL) prior to delivery, we attempted to use the extrauterine incubation system on a goat fetus. It was hypothesized that consecutive ischemia and reperfusion to the brain of premature fetuses caused by transient umbilical venous compression could be a causative agent in the induction of PVL. Eleven goat fetuses of approximately 125 days gestational age (term 145 days) were incubated using extrauterine incubation system with arterio-venous extracorporeal membrane oxygenation (A-V ECMO). Acatheter connected to the umbilical vein was occluded completely (total occlusion in 5 cases) or partially (75% occlusion in 6 cases) for 15 seconds and then relieved from occlusion. Total volume of blood stored in a syringe during the occlusion was transfused over the next 45 seconds through the catheter. This procedure was repeated consecutively 6 times at intervals of 5 minutes. After the procedure, extrauterine incubation was c … More ontinued for up to 4 days. The goat fetus was then sacrificed, and the brain tissue was examined histopathologicaUy for the presence PVL lesions. During occlusion of the umbilical vein catheter, there was a significant decrease in fetal heart rate, fetalblood pressure and flow volume of the carotid artery as well as the amplitude of electrocorticogram. However, each of these recovered soon after relief from occlusion. There were no apparent differences between pre- and post- procedure blood gas examinations. The lesion of coagulation necrosis, which was recognized as the primary lesion of PVL, could be observed in the deep white matter surrounding the lateral ventricle in seven out of eleven goat fetuses. These results suggest that consecutive umbilical venous compression causing ischemia and reperfusion to the brain of premature fetuses may play an important role in the induction of PVL. As well, the extrauterine incubation system could provide an experimental animal model to investigate fetal pathology. Less