未成熟新生大鼠低氧缺血性脑损伤对轴突的密度以及突触形成的影响

Rats with hypoxic-ischemic brain injury affects the axon density and synaptic formation

目的探讨大鼠低氧脑损伤对于轴突的密度以及突触形成的影响情况。方法 3日龄SD新生大鼠随机分为两组,正常对照组和低氧处理组,正常对照组不给予任何处理,低氧缺血处理组大鼠行左颈总动脉结扎术后入自制封闭容器,充以8%O2+92%N2的混合气体,低氧处理时间为90 min,之后恢复正常氧供。待大鼠10日龄时进行银染探讨两组轴突密度情况,28日龄时(造模后第25天)分别取大鼠的大脑海马组织以及侧脑室组织进行电镜观察,并进行突触的计量分析。结果银染结果提示低氧缺血处理之后大鼠脑组织中的轴突密度明显降低;电镜结果显示,与正常对照组相比,低氧处理组的大脑海马以及侧脑室组织均出现明显增多的神经元胞核固缩、碎裂;统计分析结果表明,与正常对照组相比,低氧组的大脑海马以及侧脑室组织的突触数量明显降低。结论大鼠低氧缺血性脑损伤影响了轴突的密度以及突触的形成,进而导致相关的功能损伤。

Objeetive To explore the effect of hypoxic - ischemic brain injury for the axon density and synapse formation condition in the rats. Methods Three days old neonatal SD rats were randomly divided into two groups, normal, control group and hypoxic - ischemic group. The normal control group were not given any treatments. The hypoxic - ischemic group rats were taken into the closed container, filled with 8% 02 ＋ 92%N2 mixed gas, charging time was 90 minutes. The brains of the rats were taken when they were 10 days of age to analyze the axon density. The hippocampus tissue and lateral ventricular tissue of the rats＇brain were taken to carry out electron microscope analysis to compare the number of synapses between two groups at 28 days of age. Results Result of Bielschowsky silver staining indicated that the axon density was decreased dramatically. The electron microscope showed that hypoxia group of brain hippocampus and lateral ventricle tissue appeared significantly increased neuronal cell nuclear pyknosis and fragmentation compared with the normal control group. The statistical analysis results show that the number of synapses in brain hippocampus and lateral cerebral ventricular tissue of hypoxia group reduced obviously compared with the normal control group. Conclusion Hypoxic brain injury in rats affected the formation of synapses, which led to the corresponding functional injury.