缺血再灌注对大鼠海马CA1及DG神经元内19S蛋白酶体影响的激光扫描共聚焦显微镜研究

目的探讨缺血再灌注对大鼠海马CA1及海马齿状核(DG)神经元内19S蛋白酶体的影响。方法采用20min全脑缺血的大鼠模型,20只大鼠分为5组,分别为假手术组及按照再灌注时间分为30min组,4h组,24h组,72h组,每组4只。采用含有4%多聚甲醛的PBS液体进行灌注,取出脑组织,放于多聚甲醛中固定24h后行冠状切片,应用免疫组织化学法标记抗19S蛋白酶体抗体,应用激光共聚焦显微镜对组织切片进行观察。结果大鼠海马区CA1神经元内19S蛋白酶体在缺血再灌注30min后开始减少,4h略增高,然后逐渐减少,直至72h细胞大部份死亡;DG神经元内的19S蛋白酶体也于再灌注30min后减少,4h略增高,然后逐渐减少,至24h程度最重,72h则有所恢复。结论全脑缺血再灌注后,海马CA1及DG神经元内19S蛋白酶体的变化影响了神经元内蛋白的降解,是导致缺血后神经元死亡的一个因素。

Influence of cerebral ischemia/reperfusion on 19S proteasome in hippocampal CA1 and dentate gyrus of rat

Objective To explore the influence of ischemia/reperfusion on 19S proteasome in hippocampal CA1 and dentate gyrus (DG) of rats by laser scanning confocal microscope. Methods In a total of 20 male Wistar rats, 16 underwent global cerebral ischemia for 20 min and then were reperfused with PBS solution containing 4% polyformaldehyde for 30 min, 4, 24, 72 h, respectively (n=4 in each group), and the other 4 get a sham operation. Following modeling, the brain was taken out and put into fixation solution; 24 h later, the brain tissue was cut into coronal slices with vibratome. When the brain slices were labeled with anti-19S proteasome antibody by immunohistochemistry methods, observation was performed with laser scanning confocal microscope. Results 19S proteasome in the neurons of hippocampus CA1 began to decrease after 30 min reperfusion, increased at 4 h, then again decreased gradually until 72 h; 19S proteasome in the neurons of DG began to decrease after 30 min reperfusion, increased at 4 h, then again decreased gradually until 24 h, and recovered again at 72 h. Conclusion Global cerebral ischemia/reperfusion-induced changes of 19S proteasome level in hippocampal CA1 and DG of rats is one of the factors leading to the neuron death after transient ischemia.