[Gly14]-Humanin对局灶性脑缺血再灌注损伤大鼠神经保护作用及自由基代谢的影响

Effect of [Gly14]-Humanin on Neuroprotectant and Free Radicals Metabolism in Rats of Focal Cerebral Ischemia Reperfusion Injury

关键词:  脑缺血再灌注  [Gly14]-Humanin  神经保护  脑水肿  自由基  细胞凋亡

Key words:  cerebral ischemia/reperfusion  [Gly14]-Humanin  neuroprotection  brain water content  free radicals  cell apoptosis

摘要:

目的 观察[Gly14]-Humanin（HNG）预处理对局灶性脑缺血再灌注损伤后大鼠神经功能保护及自由基代谢的影响。方法 将96只健康♂ 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连续5 d尾静脉注射5 μL生理盐水，每日1次；HNG组给予100 nmol·L^-1 HNG 5 μL，而模型组除正常饲养外，术前不接受任何处理。各组大鼠在缺血4.5 h再灌注24 h后进行神经功能缺损评分（NDS），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，检测脑组织超氧化物歧化酶（SOD）的活性、谷胱甘肽（GSH）及丙二醛（MDA）的含量水平，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 与假手术组相比，其余3组大鼠的NDS、脑组织含水量、SOD的活性及GSH含量水平均降低，而MDA含量水平及细胞凋亡数升高，差异均有统计学意义（P<0.01）。与生理盐水组及模型组相比，HNG组大鼠的NDS、脑组织含水量、SOD的活性及GSH含量水平均升高，而MDA含量水平及细胞凋亡数降低，差异均有显著性（P<0.05）。HNG组大鼠凋亡细胞数与GSH含量水平呈正相关（r=0.462，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，增加脑组织抗氧化物质SOD的活性及GSH含量水平，减少神经细胞的凋亡，从而减轻临床神经功能缺损。

Abstract:

OBJECTIVE To study the effect of[Gly14]-Humanin(HNG) on neuroprotectant and free radicals metabolism in rats of focal cerebral ischemia reperfusion injury. METHODS Ninety-six healthy male Sprague-Dawley rats were randomly divided into sham-operation group, model group, normal saline group and HNG group, with 24 rats in each group. Rat model of acute middle cerebral artery occlusion (MCAO) and reperfusion was established by suture embolism, relevant medicines (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 5 days before operation respectively(iv, five times, qd). After cerebral ischemia 4.5 h and 24 h of reperfusion, neurological deficit score(NDS), brain water content, detect the activitiy of SOD, levels of GSH and MDA in cerebral tissue, HE staining was used to observe morphologic changes of neuron cells in ischemia region, TUNEL staining was used to detect the number of neuron apoptosis were penformed for each group. Then the linear correlation analysis was used to determine the assocination between the levels of GSH and neuron apoptosis in cerebral tissue with HNG group. RESULTS Compared with sham-operation group, the NDS, the brain water content, the activitiy of SOD and levels of GSH were significantly decreased, but the levels of MDA and number of neurocytes apoptosis were significantly increased in the other three groups(P<0.01). Compared with normal saline group and model group, the NDS, the brain water content, the activitiy of sod and levels of GSH were significantly increased, but the levels of MDA and number of neurocytes apoptosis were significantly decreased in HNG group(P<0.05). The number of neurons and levels of GSH in HNG group were perfect positive correlations(r=0.462, P<0.001). CONCLUSION [Gly14]-Humanin can mitigate the neurologic deficit. Its mechanism is probably related to lighten the brain water content, increase the activitiy of SOD and levels of GSH, resistance focal cerebral ischemia reperfusion injury, decrease the neuro apoptosis of ischemic area.