未成熟胎兔缺氧缺血性脑损伤模型的建立

The establishment of a hypoxic-ischemic brain damage model in preterm fetal rabbits

目的：建立合适的早产脑损伤动物模型。方法选择孕25 d的健康新西兰白兔32只，阻断孕兔子宫血供，致胎兔宫内缺氧缺血，阻断时间分别持续30 min、35 min、37 min、40 min，对照组不阻断子宫血供。所有孕兔分别在术后24 h （孕26 d，A组）、5 d（孕30 d，B组）行剖宫产，根据阻断时间共分8亚组，每亚组4只。记录新生兔的一般状况，评估胎龄30 d存活新生兔神经行为学，观察脑组织病理改变。结果 A组新生兔缺氧缺血30 min均存活，随时间延长（35~40 min），死胎率由31.0%升至100%，存活新生兔脑组织含水量、凋亡脑细胞数随时间推移逐渐增加，以上差异均有统计学意义（P均〈0.05）。B组新生兔，缺氧缺血35和37 min的死胎率升高为50.0%和65.7%，存活兔的体质量均低于对照组，并有不同程度的神经行为学异常，以上差异均有统计学意义（P〈0.05）。脑组织病理检查发现，B组脑白质损伤较A组更明显。结论孕25d持续阻断孕兔子宫血供35~37 min可造成部分死胎和宫内体质量增长迟缓，存活新生兔出现不同程度的神经行为学异常及脑白质损伤，可用于制备早产缺氧缺血性脑损伤动物模型。

Objective To establish an appropriate preterm hypoxic-ischemic brain injury animal model. Methods A total of 32 pregnant New Zealand white rabbits at gestational day 25 were selected. The uterine blood supply in pregnant rabbits was blocked for 30, 35, 37, 40 minutes respectively, while in the control group it was not blocked. Then the pregnant rabbits were subjected to cesarean section 24 hours （at embryonic day 26, A group） or 5 days （at embryonic day 30, B group） after the experimental procedure. The general conditions of the newborn rabbits were recorded. The degree of neurobehavioral impairment in newborn rabbits was evaluated. The histological changes of brain tissue were observed. Results In A group, all newborn rabbits survived with ischemia for 30 minutes, while the stillbirth rates increased from 31.0% to 100% with ischemia from 35 to 40 minutes. In survived nowborn rabbits, the brain water content and the number of apoptotic brain cells were increased with prolonged ischemia. All these differences were statistically significant （all P〈0.05）. In B group, the stillbirth rates increased to 50.0% and 65.7% respectively with ischemia for 35 or 37 minutes. The birth weight of survived newborn rabbits were significantly lower than that in the control group. The neurobehavioral test scores were significantly lower in ischemic groups than that in the control group. All these differences were statistically significant （all P〈0.05）. The pathological examination of brain tissue found that the white matter damage in B group was more obvious than that in A group. Conclusions Continuous blockage of uterine blood supply in pregnant rabbits at gestational day 25 causes stillbirth, neurobehavioral damages and white matter injury as well as fetal rabbit intrauterine growth restriction, which can be used for the preparation of preterm hypoxic-ischemic brain injury animal model.