脑缺血大鼠血清生长因子的动态变化及重组人生长激素对血管性痴呆模型大鼠作用的研究

发布时间：2019-04-03 11:27

【摘要】：目的:观察慢性脑缺血大鼠血清及脑组织生长激素及血清生长因子的动态变化;以及重组人生长激素(recombinant human growth hormone,rhGH)对血管性痴呆(vascular dementia,VD)大鼠血清生长因子及学习记忆的影响,探讨重组人生长激素对VD脑保护作用的机制。方法:1、采用Morris水迷宫筛选学习记忆能力正常的雄性SD大鼠143只,随机分入各实验组,采用间断性结扎大鼠双侧颈总动脉法制备慢性脑缺血所致VD大鼠模型,术后,给药组颈部皮下注射rhGH,给药28d后,进行Morris水迷宫实验,观察各组大鼠学习记忆能力情况;2、在脑缺血后各时间点分别从相应实验组选取8只大鼠,采用酶联免疫吸附法(ELISA)检测血清、皮质和海马组织匀浆中的血管内皮生长因子(vascular endothelial growth factor,VEGF)、胰岛素样生长因子-1(insulin-likegrowthfactor-1,IGF-1)和生长激素(growth hormone,GH)的水平变化;另一部分大鼠断头取脑制作脑组织石蜡切片,进行HE染色和TUNEL凋亡染色,观察海马CA1区病理学变化和神经元的凋亡程度,采用Image Pro Plus图像处理软件处理TUNEL凋亡染色图片,统计IOD值。结果:1、脑缺血大鼠VEGF、IGF-1和GH活性水平测定分析,与正常组相比,模型组血清、皮质及海马vegf、igf-1及gh活性水平随脑缺血时间延长均降低且有显著差异性(p0.05);并且血清、皮质和海马vegf、igf水平和gh水平之间存在正相关性;在he染色中,模型组大鼠随缺血时间增加海马ca1区细胞排列紊乱,分布稀疏,细胞形状不规则,细核变形,出现核固缩、溶解,而正常组无此改变;2、在水迷宫实验中,随着训练天数的增加,各组逃避潜伏期均缩短。定位航行实验第六天,假手术组、模型组(28d)、重组人生长激素组(28d)逃避潜伏期分别为5.29±3.41s、23.45±3.58s和7.30±5.39s,空间探索实验穿越平台次数分别为5.87±3.27、1.32±1.19、3.14±1.50,可以发现:与正常组比较,模型组(28d)大鼠学习记忆能力显著下降,差异有统计学意义(p0.05),说明模型制备成功。与模型组(28d)比较,重组人生长激素组(28d)学习记忆能力显著增加,差异有统计学意义(p0.05),较正常组差异无统计学意义。重组人生长激素组大鼠vegf、igf-1和gh水平测定分析,与模型组相比,重组人生长激素组血清、皮质及海马vegf、igf-1及gh活性水平增高且有显著差异性(p0.05);tunel凋亡染色观察发现,与模型组比较,重组人生长激素组海马ca1区神经元阳性染色减少且分布密度有所增加;与模型组比较,重组人生长激素组iod值降低,差异有统计学意义(p0.05)。结论:慢性脑缺血导致血清、皮质和海马igf-1及vegf均减少,并且与血清、皮质和海马gh水平具有直线相关性。rhgh可以增加vd大鼠gh、igf-1及vegf水平,改善其学习记忆及认知功能障碍,减轻海马神经元凋亡,提示rhgh对vd大鼠慢性缺血性脑损伤具有保护作用。
[Abstract]:Objective: to observe the dynamic changes of serum and brain growth hormone and serum growth factor in rats with chronic cerebral ischemia. And the effect of recombinant human growth hormone (recombinant human growth hormone,rhGH on serum growth factor and learning and memory in rats with vascular dementia (vascular dementia,VD), and to explore the mechanism of the protective effect of recombinant human growth hormone on the brain of VD. Methods: 1143 male SD rats with normal learning and memory ability were screened by Morris water maze and randomly divided into each experimental group. Chronic cerebral ischemia-induced VD rats were established by intermittent ligation of bilateral common carotid artery. Twenty-eight days after subcutaneous injection of rhGH, into the neck of the treatment group, Morris water maze test was performed to observe the learning and memory ability of the rats in each group. 2. At each time point after cerebral ischemia, 8 rats were selected from the corresponding experimental group, and the levels of vascular endothelial growth factor (vascular endothelial growth factor,VEGF in serum, cortex and hippocampus homogenate were detected by enzyme-linked immunosorbent assay (ELISA). Changes of insulin-like growth factor-1 (insulin-likegrowthfactor-1,IGF-1) and growth hormone (growth hormone,GH) levels; The other part of rats were decapitated to make paraffin sections of brain tissue, HE staining and TUNEL apoptosis staining were used to observe the pathological changes of hippocampal CA1 region and the degree of neuron apoptosis, and Image Pro Plus image processing software was used to process the images of TUNEL apoptosis staining. Statistical IOD value. Results: 1. The activity levels of VEGF,IGF-1 and GH in cerebral ischemia rats were measured and analyzed. Compared with normal group, vegf, in serum, cortex and hippocampus of model group were measured and analyzed. The activity levels of igf-1 and gh decreased with the prolongation of cerebral ischemia time and showed significant difference (p0.05). There was a positive correlation between the levels of vegf,igf and gh in serum, cortex and hippocampus. In he staining, with the increase of ischemia time, the cells in the ca1 region of hippocampus in the model group were disarranged and distributed sparsely, the shape of the cells was irregular, the fine nucleus was deformed, the nucleus was condensed and dissolved, but there was no such change in the normal group. 2. In the water maze test, the escape latency was shortened with the increase of training days. The escape latencies of sham operation group, model group (28 days) and recombinant human growth hormone group (28 days) were 5.29 卤3.41 s, 23.45 卤3.58 s and 7.30 卤5.39 s, respectively. The times of crossing the platform in spatial exploration experiment were 5.87 卤3.27,1.32 卤1.19,3.14 卤1.50respectively. It was found that the learning and memory ability of the model group (28d) was significantly lower than that of the normal group (p0.05), and there was a significant difference between the two groups (p0.05). The results showed that the model was prepared successfully. Compared with the model group (28d), the learning and memory ability of the recombinant human growth hormone group (28d) was significantly increased (p0.05), but there was no significant difference compared with the normal group (p0.05). The levels of vegf,igf-1 and gh in the recombinant human growth hormone group were higher than those in the model group. Compared with the model group, the levels of vegf,igf-1 and gh in the serum, cortex and hippocampus in the recombinant human growth hormone group were significantly higher than those in the model group (p0.05). Tunel apoptosis staining showed that compared with the model group, the positive staining of hippocampal ca1 neurons in the recombinant human growth hormone group decreased and the distribution density increased. Compared with the model group, the OD value of the recombinant human growth hormone group was significantly lower (p 0.05). Conclusion: chronic cerebral ischemia can decrease the levels of igf-1 and vegf in serum, cortex and hippocampus, and have linear correlation with serum, cortex and hippocampus gh levels. Rhgh can increase gh,igf-1 and vegf levels in vd rats. It is suggested that rhgh has protective effect on chronic ischemic brain injury in vd rats by improving learning, memory and cognitive impairment and alleviating apoptosis of hippocampal neurons.
【学位授予单位】：西南医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R965

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