摘要
目的探讨脑源性神经营养因子（brain-denved neurotrophic factor，BDNF）预处理对沙土鼠脑缺血．再灌注（ischemia-reperfusion，I／R）后神经细胞凋亡及Bcl-2、Bax蛋白表达的影响。方法蒙古种沙土鼠48只，随机分为6组，每组各8只：正常对照组（C）；缺血-再灌注组（I／R），全脑缺血20min后再灌注24h；BDNF预处理6，12，24，48h组（PR6，PR12,PR24，PR48），P心，PR12，PR24，PR48各组分别于脑缺血前6，12，24，48h经侧脑室注射BDNF（0．5μg／只）进行预处理，缺血20min后分别再灌注24h。实验地点在贵阳医学院动物实验中心。采用夹闭沙土鼠双侧颈总动脉20min后去除动脉夹使血流再通的方法制作全脑I／R损伤模型，夹闭过程中出现瞳孔散大、对光反射消失及翻正反射消失等则说明产生全脑缺血。除C组外的所有动物分别于脑缺血20min再灌注24h结束时断头取脑，取视交叉后1～4mm处的额叶皮层组织制备石蜡切片，TUNEL法检测脑皮层凋亡神经细胞，免疫组化法检测Bcl-2，Bax蛋白的表达。统计分析采用方差分析法。结果C组未检测到凋亡细胞及Bcl-2，Bax蛋白阳性表达细胞；I／R组及BDNF预处理各组沙土鼠脑皮层均可检测到凋亡细胞，且BDNF预处理各组细胞凋亡指数均明显低于I／R组，P值均为0．000；与I／R组比较，BDNF预处理各组脑皮层Bcl-2蛋白阳性细胞指数均显著增高，而Bax蛋白的阳性细胞指数均显著降低，P值均为0．000；BDNF预处理各组中以6，12h预处理组的细胞凋亡指数及Bax蛋白阳性细胞指数较低，P值分别为0．056和0．001，而Bcl-2蛋白阳性细胞指数较高，P值为0．005。结论不同时间窗的BDNF预处理均能不同程度的减轻脑I／R后神经细胞凋亡，有明显脑保护作用，以脑I／R损伤前6，12h时间窗内给予BDNF预处理的脑保护效果较明显；其机制可能是通过上调Bcl-2蛋白的表达及抑制Bax蛋白的�
Objective To investigate the effects of brain-derived neurotrophic factor （BDNF） pretreatment on neuron apoptosis and the expression of Bcl-2 and Bax protein following global cerebral ischemia-reperfusion （I/R） injury in gerbils. Method Forty-eight mongolian gerbils were randomly divided into six groups in equal number （ n = 8） ： normal control group （group C）, ischemia-reperfusion group （group I/R） and four BDNF pretreatment groups according to various lengths of time from BDNF pretreatment to ischemia-reperfusion. The BDNF pretreatmerit was carried out in gerbils with lateral ventricular injection of BDNF 0.5 μg 6 h, 12 h,24 h and 48 hours before cerebral ischemia, and those gerbils assigned into PR6, PR12, PR24 and PR4s groups. The global cerebral ischemia-reperfusion was induced by occlusion of bilateral common carotid arteries for 20 minutes and then the arteries were released for 24 hours reperfusion. The confirmation of global cerebra ischemia was evidenced by the appearance of mydriasis and disappearance of light reflex and righting reflex. Twenty-four hours later, all gerbils including those of control group were sacrificed and a piece of tissue was taken from frontal cortex just behind the optic chiasma 1 - 4 millimeter for making paraffin sections. Neuron apoptosis was identified by using TUNEL and immunohisehemistry was used to detect the expression of Bcl-2 and Bax protein in cerebral cortex. The data were analyzed by using analysis of variance. Results There were no apoptotie cells, and expression of Bcl-2 and Bax protein positive cells found in group C. Neuron apoptosis in brain cortex was detected in I/R group and BDNF pretreatment groups. The indexes of neuron apoptosis in BDNF pretreatment groups were markedly lower than those in group I/R （ P 〈 0.01 ）. Compared with group I/R, the index of expression of Bcl-2 protein positive cells was increased significantly in BDNF pretreatment groups （ P = 0. 005）, while the index of expression of Bax protein positive cells w
出处
《中华急诊医学杂志》
CAS
CSCD
北大核心
2009年第8期851-855,共5页
Chinese Journal of Emergency Medicine
基金
贵州省优秀科技教育人才省长专项基金资助项目（2005-220）
关键词
脑缺血
再灌注
脑源性神经营养因子
细胞凋亡
凋亡相关基因
Brain ischemia
Reperfusion
Brain-derived neurotrophic factor
Apoptosis
Apoptotic related-genes
