未成熟鼠慢性缺氧缺血脑损伤胶质细胞及髓鞘相关蛋白变化

Changes of Oligodendrocyte and Myelin Related Protein in Premature Rats with Hypoxic Ischemic Brain Damage

目的观察3日龄未成熟大鼠慢性缺氧缺血脑损伤胶质细胞凋亡及髓鞘相关蛋白(MBP和PLP)变化,研究早产儿脑损伤的发病机制。方法将164只3日龄同窝生SD未成熟新生大鼠随机分为实验组92只和对照组72只,对照组仅切开颈部皮肤,而实验组结扎双侧颈总动脉,造成未成熟鼠缺氧缺血脑损伤,分别于不同时间点处死大鼠,采用组织切片苏木精伊红染色、少突胶质细胞抗体O4和细胞凋亡免疫组化双标记、RTPCR实时绝对荧光定量检测等方法,观察未成熟鼠脑损伤的病理变化、少突胶质细胞凋亡及MBP和PLPmRNA的表达。结果实验组未成熟鼠出现脑白质液化疏松、小胶质细胞增生和脑室扩大等病理变化,深部白质凋亡细胞计数在损伤后24、48、72h和1周较对照组增多(P<0.05),以48h两组差异最为显著,损伤后2周两组无统计学差异(P>0.05)。凋亡细胞经双标显示以少突胶质细胞为主。髓鞘相关蛋白mRNA的表达在损伤后较对照组减少。结论3日龄未成熟新生大鼠缺氧缺血脑损伤后,出现以脑白质少突胶质细胞损伤为主的病变,有助于理解早产儿脑损伤发病机制和神经病理变化,并可作为研究早产儿缺氧缺血脑损伤的动物模型。

Purpose To investigate apoptosis of oligodendrocyte、pathologic changes of myelin related protein in premature rats with hypoxic ischemic brain damage,and explore the pathogenesis of premature brain hypoxic ischemic damage. Methods The present study was conducted to employ 3rd -day SD premature rats. A total of 164 rats were randomly divided into experimental group（92） and control group（72） according a random number table. Bilateral carotid was ligated in the experimental group. The rats were killed according to the experimental plan at differental times. HE staining, the marker of oligodendrocyte progenitor, and TUNEL double immunofluorescence staining, RT-PCR real-time absolute quantification were applied to investigate the pathologic manifestation,apoptosis of oligodendrocyte and expression of myelin related protein MBP and PLP respectively. Results Brain white matter showed pathologic changes such as rarefaction, liquefaction, microglia hyperplasia and ventricular dilatation, apoptotic cell increased at 24,48,72 h and one week after damaged （P〈 0.01 ）. Most of apoptotic cell expression oligodendrocyte marker 04. The express of myelin related protein also had obvious reduction（ P 〈 0.05）. Conclusions Premature rats with hypoxic ischemic brain damage showed obvious oligodendrocyte damage in brain white matter. It is helpful to understand the pathologic change of premature infants progressively.