大鼠脑缺血-再灌注损伤后Beclin-1和LC3的表达及依达拉奉的干预作用

The Expression of Beclin-1 and LC3 on Rats with Cerebral Ischemia Reperfusion Injury and the Efficacy of Edaravone

目的:检测大鼠脑缺血-再灌注损伤模型中自噬相关蛋白Beclin-1和LC3在皮层和海马区表达以及依达拉奉的干预。方法:将SD大鼠(雄性)随机分为以下几组:假手术组、模型组、依达拉奉组。采用Zea Longa线栓法通过大脑中动脉阻塞2 h再灌注24 h制备脑缺血-再灌注模型,其中假手术组仅分离左侧颈总动脉。剂量为10 mg/kg的依达拉奉于再灌注前15 mim经腹腔注射。采用神经行为学评分评估大鼠脑神经损伤表现;TTC染色判断模型是否成功和脑部损伤程度;对大鼠神经元细胞进行HE染色,观察其在皮层和海马区的变化;免疫组化检测Beclin-1和LC3的表达。结果:脑缺血-再灌注24 h后,依达拉奉组神经行为学评分为(2.00±0.67),显著低于模型组的(2.50±0.53)(P<0.05)。模型组大鼠脑部观察到梗死灶出现,皮层和海马区神经元受损伤,依达拉奉组上述症状减轻。皮层区假手术组、模型组、依达拉奉组的Beclin-1阳性表达率分别为(11.08±0.85)%、(33.42±1.57)%和(25.61±1.39)%,模型组与假手术组和依达拉奉组比较差异都有统计学意义(P<0.05);海马区假手术组、模型组、依达拉奉组的Beclin-1阳性表达率分别为(10.34±0.21)%、(31.82±1.73)%和(22.74±1.26)%,模型组与假手术组和依达拉奉组比较差异都有统计学意义(P<0.05)。皮层区LC3的阳性表达率分别为(15.33±0.47)%、(39.72±1.73)%和(28.53±1.61)%,模型组与假手术组和依达拉奉组比较差异都有统计学意义(P<0.05);海马区LC3的阳性表达率分别为(13.74±0.37)%、(32.53±1.43)%和(25.38±1.23)%,模型组与假手术组和依达拉奉组比较差异都有统计学意义(P<0.05)。结论:脑缺血-再灌注后Beclin-1和LC3表达水平增加,而依达拉奉可能通过下调它们的表达减少自噬发生,减轻脑损伤。

Objective： To study the expressione of autophagy-related protein Beclin-1 and LC3 in cortex and hippocampus of rats after cerebral ischemia reperfusion injury and the efficacy of Edaravone. Methods： Sprague Dawley rats were randomly divided into sham group, model group and Edaravone group. The cerebral ischemia reperfusion model was induced via Zea Longa with blocking the middle cerebral artery of 2 h and reperfusing of 24 h. Animals assigned to sham group were only separated left common carotid artery. Edar- avone was injected intraperitoneally at a dose of 10 mg/kg at 15 min before reperfusion. The condition of nerve injury of rats was conducted by Neurobehavioral score. The degree of brain injury and success of model were determined based on 2,3,5-triphenyltetrazolium chloride（TTC）staining. The changes of neuron stained by hematoxylin and eosin （HE） in cortex and hippocampus were observed. The ex- pression of Beclin-1 and LC3 was measured by immunohistochemistry. Results： After cerebral ischemia reperfusion the neurobehavioral score of edaravone group was（2.00±0.67）, which was obcviously less than（2.50±0.53） of model group（P 〈0.05）. The infraction focus and the neuron injury in cortex and hippocampus neurons were also observed in model group, and the edaravone group reduced above expression. The positive rate of Beclin-1 of each group in cortex were （11.08± 0.85）%, （33.42± 1.57）% and （25.61±1.39）%, there was significant difference between model group with sham group and edaravone group （P 〈0.05）. The positive rate of Beclin-1 of each group in hippocampus were （10.34± 0.21）%, （31.82±1.73）% and （22.74± 1.26）%, there was significant difference between model group with sham group and edaravone group（P〈0.05）. The positive rate of LC3 of each group in cortex were （15.33± 0.47）%, （39.72± 1.73）% and （28.53± 1.61）%, there was significant difference between model group with sham group and edaravone group（P〈0.05）. The positive rate of LC3 of each group in hippocampus were （13.74± 0.37）%, （32.53 ± 1.43）% and（25.38 ±1.23）%, there was significant difference between model group with sham group and edaravone group （P〈0.05）. Conclusion： The expression of Beclin-1 and LC3 was increased after cerebral ischemia reperfusion. Edaravone may reduce autophagy and brain injury through downregulation the expression of Beclin-1 and LC3.