[Gly14]-Humanin对大鼠局灶性脑缺血再灌注损伤的影响及其机制研究

关键词：脑缺血再灌注  [Gly14]-Humanin  脑水肿  干扰素-γ  核因子-κB p65  细胞凋亡  神经保护  神经细胞

Keywords:cerebral ischemia/reperfusion  [Gly14]-Humanin  brain water content  nuclear transcription factor-κB p65  interferon-γ  cell apoptosis  neuroprotection  neurocyte

摘要：

      摘要 目的：通过观察[Gly14]-Humanin（HNG）预处理对大鼠局灶性脑缺血再灌注损伤后神经功能缺损评分、脑水肿、细胞凋亡及炎症反应等方面的影响，探讨其相关的神经功能保护机制。 方法：将96只健康雄性SD大鼠随机分为HNG组、生理盐水组、模型组及假手术组，每组24只。采用改良的Zea-longa线栓法建立大脑中动脉缺血再灌注损伤模型，生理盐水组与假手术组大鼠术前7天给予生理盐水（2ml/kg）连续尾静脉注射，每日1次；HNG组给予HNG（2μl/kg），而模型组除正常饲养外术前不接受任何处理。各组大鼠在线栓法造模成功后6h，再拔除线栓恢复血液灌注24h后进行神经功能缺损评分（NDS），开阔法观察SD大鼠脑缺血再灌注后行为学改变；采用干湿质量法检测脑组织含水量、HE染色观察缺血区病理学改变，ELISA法测定大鼠脑组织核因子-κB p65（NF-κB p65）及干扰素-γ（IFN-γ）水平，原位末端标记染色观察凋亡细胞数并进行统计学分析。 结果：①与假手术组相比，其余3组大鼠的NDS、脑组织含水量、NF-κB p65及IFN-γ水平及细胞凋亡数均升高，而行为学指数降低，差异有显著性意义（P<0.01—0.05）；②与生理盐水组及模型组相比，HNG组大鼠的NDS、脑组织含水量、NF-κB p65和IFN-γ水平、细胞凋亡数降低，而行为学指数增高，差异有显著性意义（P<0.01—0.05）；③HNG组大鼠脑组织IFN-γ与NF-κB p65含量水平呈正相关（r=0.762，P<0.001）。 结论：HNG预处理减轻脑缺血再灌注损伤过程中的脑水肿，下调脑组织中NF-κB p65的水平，减少促炎介质（IFN-γ）的释放，抵制神经细胞的凋亡，从而减轻临床神经功能的缺损。

Abstract:

      Abstract Objective: To study the effect of [Gly14]-Humanin (HNG) on focal cerebral ischemia reperfusion injury in rats and its mechanism. Method: Ninety-six healthy male Sprague-Dawley rats were randomly divided into HNG group, normal saline group, model group and sham-operation group, with 24 rats in each group. A rat model of acute middle cerebral artery occlusion (MCAO) and reperfusion was established by suture embolism, relevant (normal saline in the rats of the sham-operation group and normal saline group, HNG in the rats of the HNG group) were given to rats 7 days before operation respectively (iv, seven times, qd). After 6h after cerebral ischemia and 24h after reperfusion, neurological deficit score (NDS) were performed for each group, the ethological index of rats was counted by the open field method; brain water content of the ischemic areal was performed for each group, ELISA was used to detect the levels of NF-κB p65 and IFN-γ in cerebral tissue, HE staining is used to observe morphologic changes of neuron cells in ischemia region and TUNEL staining was used to detect the number of neuron apoptosis. Then the linear correlation analysis was used to determine the association between the levels of IFN-γ and NF-κB p65 in cerebral tissue with HNG group. Result: ①Compared with sham-operation group, the NDS, the brain water content, the levels of NF-κB p65, IFN-γ and the number of neurocytes apoptosis were significantly increased, but the behavioral mark was decreased in the other three groups (P<0.01—0.05); ②Compared with normal saline group and model group, the NDS, the brain water content, the levels of NF-κB p65, IFN-γ and the number of neurocytes apoptosis were significantly decreased, but the behavioral mark was increased in HNG group (P<0.01—0.05); ③The levels of IFN-γ and NF-κB p65 in HNG group showed perfect positive correlations(r=0.762, P<0.001). Conclusion: [Gly14]-Humanin can mitigate the neurologic deficit. Its mechanism is probably to lighten the brain water content, down-regulate NF-κB p65 levels and then reduce the release of IFN-γ in the process of the focal cerebral ischemia reperfusion, therefore to inhibit the apoptosis of neurons of ischemic area.