葛根素对脑缺血再灌注大鼠海马组织中Bcl-2、Beclin1及LC3蛋白表达的影响

Effects of puerarin on the expression of Bcl-2,Beclin1 and LC3 proteins in cerebral ischemia-reperfusion hippocampus of rats

目的观察葛根素对脑缺血再灌注大鼠海马组织中Bcl-2、Beclin1及LC3表达的影响。方法 28只雄性SD(250~300g)大鼠随机分为假手术组、模型组、葛根素低剂量(50mg/kg)组和葛根素高剂量(100mg/kg)组。连续给药7 d,末次给药1 h后,建立大脑中动脉闭塞模型,缺血90 min后,再灌注24 h,评估神经功能,采用TTC染色观察脑梗死面积,Western Blotting法检测缺血侧海马组织中Bcl-2、Beclin1及LC3蛋白表达的变化。结果与假手术组比较,模型组的大鼠神经功能损伤显著增强,脑梗死面积增加,Bcl-2蛋白表达显著下调,Beclin1蛋白表达显著上调,LC3-II/LC3-I的比值显著上升;与模型组比较,葛根素低、高剂量组随着剂量的增加,大鼠的神经功能损伤逐渐改善,脑梗死面积逐渐减小,Bcl-2的表达逐渐上调,Beclin1的表达逐渐下调,LC3-II/LC3-I的比值逐渐下降,呈剂量依赖性。结论葛根素可通过调控脑缺血/再灌注后凋亡基因Bcl-2的表达,下调自噬相关蛋白Beclin1及LC3蛋白表达,抑制过度自噬,继而达到保护缺血性中风损伤的目的。

Objective To observe effects of puerarin on the expression of Beclin1、Bcl-2 and LC3 proteins in the hippocampal tissue of rats with cerebral ischemia-reperfusion injury. Methods Male Sprague-Dawley（ SD）（ 250-300 g） rats were randomly divided into： sham group,model group,low-dose puerarin group（ 50 mg/kg）,high-dose puerarin group（ 100 mg/kg）. After 7 days pretreatment,the middle cerebral artery occlusion（ MCAO） model was established 1 h after the last administration according to Longa＇s method. After 90 min MCAO and 24 h reperfusion,the neurological deficit scores were assessed,the infarct volume was calculated by 2,3,5-triphenyltetrazolium chloride（ TTC） staining and the expressions of Bcl-2,Beclin1 and LC3 were detected by Western Blotting. Results Compared with the rats in the sham group,the model group rats＇ neurological deficit scores,infarct volume,the expression of Bcl-2 was significantly enhanced,while Beclin1 and LC3-II/LC3-I expressions,remarkably reduced. Compared with the model group,as the dose of puerarin increased,the neurological impairment of rats gradually improved,the area of cerebral infarction gradually decreased,the expression of Bcl-2 gradually increased,the expression of Beclin1 and LC3-II/LC3-I gradually decreased,and in a dose-dependent manner. Conclusion Puerarin can alleviate excessive autophagy by regulating the expression of Bcl-2,Beclin1 and LC3 proteins after cerebral ischemia/reperfusion,and then protect against ischemic stroke injury.