不同缺氧时间制作新生大鼠脑室周围白质软化动物模型的比较

目的通过比较不同的缺氧时间,创建与人类早产儿脑室周围白质软化（periventricular leukomMacia,PVL）病理相似的可靠PVL动物模型。方法对2Et龄新生大鼠进行双侧颈总动脉结扎,分为缺氧2h组,缺氧1h组,缺氧0.5h组和缺氧0h组,另设Sham组。分别于术后2d比较各组动物死亡率,并进行大体和光镜下脑病理评估。结果缺氧大于0.5h有更高的动物死亡率（X^2=58.464,P〈0.01）,缺氧0.5h组和缺氧0h组在死亡率之间的差异无统计学意义（X^2=0.18,P=0.672）。脑大体病理显示,缺氧大于0.5h以液化坏死为主,缺氧0.5h和0h则以脑水肿或萎缩为主。光镜下脑病理显示,缺氧大于0.5h,其病变涉及灰质和白质。缺氧0.5h和0h,则主要造成白质损伤,皮质神经元损伤轻微。Sham组则无脑病理改变。结论对2日龄新生大鼠进行双侧颈总动脉结扎伴缺氧0.5h,创建PVL新生动物模型的效果最为理想。

Effect of Different Hypoxia Durations on Establishment of Neonatal Rat Models of Periventricular Leukomalacia

Objective To compare the effect of different hypoxia durations on establishment of a reliable neonatal rat model of periventricular leukomalacia （ PVL）, pathologically resembling the PVL in human preterm infants. Methods Ligation of bilateral common carotid arteries was performed in two-day old neonatal rats. Then, they were randomly divided into 4 groups： the 2-h hypoxia group, 1-h hypoxia group, 0.5-h hypoxia group and 0-h hypoxia group. A sham operation group was matched additionally. The death rate and brain pathological examination by light microscopy were assessed on day 2 after operation, respectively. Results There was a higher death rate in the 2-h and 1-h hypoxia groups （ X2 = 58.464, P 〈 0.01 ）, statistically no significant difference in death rate was found between the 0.5-h hypoxia group and 0-h hypoxia group （ X2 = 0.18, P = 0.672）. The gross examination of the brain showed that major pathological changes were cerebral liquidation or necrosis in the groups with hypoxia time longer than 0.5 h, and cerebral edema or atrophy in the 0.5-h or 0-h hypoxia groups, respectively. The histopathological examination showed that the pathological injuries were involved in both gray and white matters in the groups with hypoxia longer more than 0.5 h, and mainly in white matter in the 0.5-h or O-h hypoxia groups, respectively. No cerebral pathologic change was found in the sham group. Conclusions The resuhs of this study suggest that ligation of bilateral common carotid followed by 0.5 h hypoxia is a most favorable method for establishment of a model of periventricular leukomalacia in 2-day old neonatal rats.