摘要
背景:核因子κB是一种重要的转录因子,激活后能促进许多靶基因转录。目的:研究核因子κB在局部脑缺血及再灌注中的表达及N-乙酰半胱氨酸预处理的影响。设计:随机分组设计、动物实验。单位:哈尔滨医科大学第二临床学院神经内科。材料:实验于2004-01/05在哈尔滨医科大学动物实验中心及病理实验室完成。选择健康雄性Wister大鼠99只,随机分3组,假手术组11只,生理盐水对照组44只,N-乙酰半胱氨酸组44只。方法:3组大鼠采用Longa等改良线栓法制备大鼠局灶性脑缺血模型。将头端加热成0.26mm直径的光滑圆球的尼龙线经颈总动脉近分叉处切口插入,扎紧颈总动脉备线,打开颈内动脉上的微动脉夹,尼龙线进入颈内动脉,N-乙酰半胱氨酸组和生理盐水对照组插入长度由颈内动脉和颈外动脉分叉部计约(18.5±0.5)mm,阻断大脑中动脉血供,假手术组插入深度<15mm,大脑中动脉血供正常。N-乙酰半胱氨酸组于缺血前30min腹腔注射N-乙酰半胱氨酸(150mg/kg),生理盐水对照组于缺血前30min注射等体积生理盐水。生理盐水对照组和N-乙酰半胱氨酸组于缺血6,24h,缺血6,24h再灌注1h时间点将大鼠断颈处死,每次11只。应用免疫组织化学法观察脑组织核因子κB的表达情况,红四氯氮唑染色测定各组大鼠脑梗死体积百分比,脱氧核糖核苷酸末端转移酶介导的缺口末端标记法检测脑组织细胞凋亡。主要观察指标:各组大鼠脑梗死体积百分比,核因子κBp65结合活性,凋亡细胞。结果:纳入动物99只,均进入结果分析。①缺血6h及24h再灌注1hN-乙酰半胱氨酸组梗死体积百分比分别为(8.39±2.54)%,(24.54±6.02)%,相应生理盐水对照组为(15.50±4.18)%,(32.22±3.99)%。缺血24h各组较缺血6h各组梗死灶增大,使用N-乙酰半胱氨酸组较生理盐水对照组梗死体积明显缩小(P<0.01)。②缺血及再灌注后核因子κBp65明显从胞质转移到胞核。缺血6h及24h再灌注N-乙酰半胱氨酸组p65阳性细胞率分别为(0.462±0.022)%,(0.452±0.015)%,与相应生理盐水对照组[(0.563±0.028)%,(0.554±0.013)%]比较表达减少(P<0.01)。③N-乙酰半胱氨酸预处理较生理盐水预处理凋亡细胞减少。结论:局灶脑缺血及再灌注能使核因子κBp65活化,参与脑缺血及再灌注损伤。N-乙酰半胱氨酸可抑制p65表达,减轻神经损伤,具有脑保护作用。
BACKGROUND： Nuclear factor-kappa B （NF-κB） is an important transcription factor, which can promote the transcription of many target genes after activated.
OBJECTIVE： To investigate the expressions of NF-κB in local cerebral ischemia-reperfusion and the influence of the pretreatment of the N-acetylcysteine.
DESIGN： Randomized grouping experiment with animals as subjects.
SETTING： Department of Neurology, the Second Clinical Medical College, Harbin Medical University.
MATERIALS： The experiment was finished in the Animal Experimental Center and Laboratory of Pathology of Harbin Medical University. Ninetynine male healthy Wister rats were randomly divided into 3 groups： Sham-operated group（n=11）, saline control group（n=44）, N-acetylcysteine group（n=44）.
METHODS： Rat models of cerebral ischemia were made with the method of thread blocking improved by Longa et al in rats of the three groups. A nylon line with a smooth spherical captular end of 0.26 mm in diameter made by heating was inserted through the cut of crotch of the common carotid artery. The prepared line for common carotid artery was tied tightly and the arteriole clamp of internal carotid artery was unclamped. The nylon line entered the common carotid artery and the inserted length of the saline control group and the N-acetylcysteine group from the crotch of the internal and external carotid artery was calculated about （18.5±0.5）mm in order to obstruct the blood supply of the middle cerebral artery. The inserted depth in sham-operated group was less than 15 mm and the blood supply of the middle cerebral artery was kept normal. Intraperitoneal injection of N-acetylcysteine was given with 150 mg/kg at 30 minutes before ischemia in N-acetylcysteine group and injection of normal saline was given with equal volume at 30 minutes before ischemia in saline control group. Eleven rats each time in saline control group and N-acetylcysteine group were killed by cutting off heads at the time points of ischemia 6, 24 hours, and reperfusion 1 hour after ischemia 6, 24 hours. The express of NF-κB of brain tissue was observed with immunchistochemical method. Percentage of cerebral infarction of rats in each group was determined by dyeing of tetrachloro red tetrazoline. Apoptosis of brain tissue cells was detected with terminal deoxynucleotide transferase-mediated dUTP nick-end labeling （TUNEL）.
MAIN OUTCOME MESURES： Percentage of cerebral infart volume of rats in each group, the activity of combination of the NF-κB and apoptosis of cells.
RESULTS： Ninety-nine animals attended the experiment, all of them entered the final analysis. ① Percentages of infarct volume at 1 hour of ischemia and 6, 24 hours of reperfusion in N-acetylcysteine group were （8.39±2.54）%, （24.54±6.02）% respectively, and that of corresponding saline control group were （15.50±4.18）%, （32.22±3.99）%. The focus of infartion with ischemia for 24 hours in each group was increased as compared with that for 6 hours and the infarct volume in group with N-acetylcysteine was obviously decreased as compared with that in saline control group （P 〈 0.01）. ② NF-κB p56 transfered from the kytoplasm to the nucelus after the ischemia and reperfusion. The rates of p56 masculine cells in N-acetylcysteine group of ischemia for 6 and 24 hours were （0.462±0.022）%, （0.452±0.015）% respectively, the express of which was decreased as compared with that in saline control group [（0.563±0.028）%, （0.554±0.013）%] （P 〈 0.01 ）.③ Cells of apoptosis pretreated with Nacetylcysteine were obviously decreased as compared with that pretreated with normal saline.
CONCLUSION： Focal cerebral ischemia and reperfusion can activate NF- κB p65, which participate in the damage of cerebral ischemia and reperfusion. NF-κB can inhibit the express of p65, and relieve the nerve injury and so have the effct of protection for brain.
出处
《中国临床康复》
CSCD
北大核心
2006年第16期167-170,共4页
Chinese Journal of Clinical Rehabilitation
基金
黑龙江省自然科学基金资助项目(D01-38)~~
