局灶性脑缺血大鼠海马CA3区突触体素的动态表达

背景突触体素(synaptophysin,SYN)与神经生长、修复、再生和突触重塑密切相关,成为近年来医学研究的热点.以往学者对脑缺血再灌注大鼠模型顶叶突触体素表达研究较多.采用线栓法堵塞大鼠大脑中动脉,建立局灶性脑缺血模型,观察海马CA3区突触体素的动态表达,可为临床研究脑缺血后神经重塑提供理论依据.目的研究局灶性脑缺血后海马CA3区突触体素的动态表达以及神经修复的可塑性.设计随机对照的实验研究.单位承德医学院附属医院老年病科、承德医学院解剖教研室和河北医科大学.材料选取健康成年SD大鼠40只,随机分为脑缺血组和对照组,每组又分为7,14,21,30 d 4个时间点,每个时间点取5只大鼠.干预采用线栓法建立大脑中动脉脑缺血大鼠模型,采用苏木精-伊红染色,光镜下观察有无梗死灶.应用免疫组化技术观察海马CA3区突触体素的表达.主要观察指标①苏木精-伊红染色结果.②海马CA3区突触体素的表达.结果假手术组在大脑皮质及海马区,苏木精-伊红染色可见神经元呈层状分布,各层细胞数量较多,形态完整,细胞核圆大且核仁明显,核仁被染成紫色,胞浆呈浅粉色,神经元同周围组织间无空隙存在.缺血组可见梗死灶,表现为正常结构消失,排列紊乱,细胞数量减少,胞核固缩、深染.假手术组SYN阳性神经元的吸光度值各时间点比较差异无显著性意义(P＞0.05).实验组同假手术组比较,SYN吸光度值明显降低(P＜0.01),组内7～21 d时的吸光度值逐渐升高,且差异有显著性意义(P＜0.01),30 d时SYN的吸光值降低,但同21 d时相比差异无显著性意义(P＞0.05).结论脑缺血损伤后海马CA3区突触体素表达减少,但机体自身存在着神经元的修复和再生,可使突触体素的表达逐渐上调.

Dynamic expression of synaptophysin in hippocampal CA3 of focal cerebral ischemic rats

BACKGROUND: Synaptophysin (SYN) is closely correlated with the growth, restoration, regeneration and synaptic reconstruction, and it becomes a hotspot in medical researches recently. There are quite a lot previous researches regarding the SYN expression in the parietal lobe on cerebral ischemic-reperfusion rat model. It can provide theoretic gist for clinical researched on post-cerebral ischemic neural reconstruction to observe SYN dynamic expression in hippocampus CA3 after focal cerebral ischemia on focal cerebral ischemic animal model by the occlusion of the middle-sized artery in rats with thread-ligation method.OBJECTIVE: To investigate SYN dynamic expression in hippocampal CA3 after focal cerebral ischemia and the plasticity of neural restoration.DESIGN: A randomized and controlled trial.SETTING: Department of Gerontology of the Affiliated Hospital ofChengde Medical University, Department of Anatomy of Chengde Medical University, Hehei Medical University.MATERIALS: A total of 40 healthy adult SD rats were randomly divided into cerebral ischemia group and control group. Each group was divided into4 time points of 7, 14, 21 and 30 days with 5 rats of each time point.INTERVENTIONS: Cerebral middle-sized artery ischemic rat model was established by thread-ligation method. Brain tissue was stained by HE staining for the observation of infarct focal under optical microscope. SYN expression in hippocampal CA3 was observed with immunohistochemical technique.expression in hippocampal CA3.RESULTS: Under HE staining, it could be seen in cerebral cortex and hippocampus of pseudo-operation group that neurons were distributed in layers with quite a lot of cells in each layer in integrate shape, nucleus was round and big with obvious nucleolus, which was in purple, cytoplasm was in light pink, and there was no space between neuron and its surrounding tissue; it could be seen in ischemic group that there was infarct focal, which manifested the disappearance of normal structure with disarranged arrangement, reduced cells and pycnosis and deep-stained nucleus. There was no significant difference of absorbency of SYN-positive neurons between each time point in pseudo-operation group( P ＞ 0.05).SYN absorbency was significantly decreased in study group compared with that of control group (P ＜ 0.01 ) . The absorbency gradually elevated since day 7 to day 21 with significances( P ＜ 0.01) . SYN absorbency decreased at day 30 although there was no significant difference compared with that of day 21 (P ＞ 0.05).CONCLUSION: SYN expression decreases in hippocampal CA3 after cerebral ischemic injury while there exist neuronal restoration and regeneration in the organism, which could gradually up-regulate SYN expression.