Ghrelin对蛛网膜下腔出血后早期脑损伤的保护作用研究

发布时间：2018-05-29 16:50

本文选题：Ghrelin + 蛛网膜下腔出血　；参考：《第二军医大学》2015年硕士论文

【摘要】：目的蛛网膜下腔出血,特别是动脉瘤破裂导致的蛛网膜下腔出血是一种致死率和致残率很高的疾病,蛛网膜下腔出血导致的中风,占中风总数的5-7%,脑血管痉挛和早期脑损伤是蛛网膜下腔出血患者通常要面临的两个主要并发症,在研究初期研究人员主要把他们的精力集中在脑血管痉挛的研究上,并认为这可能是导致蛛网膜下腔出血患者预后不佳的主要原因。为了阻止脑血管痉挛导致的二次脑损伤,研究人员进行了很多的动物实验和临床试验,当脑血管痉挛被很好的控制之后,人们发现并没有能很好的改善蛛网膜下腔出血患者的预后。近年来研究发现,早期脑损伤(early brain injury EBI)可能是导致蛛网膜下腔出血患者预后不佳的重要原因。应此,探索蛛网膜下腔出血后早期脑损伤的发生机制,寻找有效的治疗手段很有必要。Ghrelin是一种含有28个氨基酸的多肽,是人类发现的第一个生长激素促分泌素的内源性配体,通过与生长激素促分泌素受体结合促进生长激素的释放发挥广泛的生物学作用,循环中的Ghrelin主要来源于胃肠道,其中大部分由胃粘膜的X/A细胞分泌,除胃肠道外Ghrelin也广泛分布于人、大鼠等多种动物的中枢神经系统和外周组织器官,如：下丘脑、垂体、心肌、胎盘及睾丸等。研究发现Ghrelin可以通过多种机制发挥神经保护功能,而P13K/Akt信号通路可能在其中发挥重要作用。本实验通过观察Ghrelin在大鼠蛛网膜下腔出血后早期脑损伤中的保护作用,并探讨其保护作用机制,为临床治疗蛛网膜下腔出血,特别是早期脑损伤提供新的思路和方法。方法100只2月龄清洁级SD雄性大鼠,体重250-300g,随机分为5组：(1)假手术组(n=20);(2)SAH模型组(n=20)；(3)SAH+溶剂组(n=20)；(4)SAH+Ghrelin组(n=20)；(5)SAH+Ghrelin+Ly294002组(n=20)。采用自体血视交叉池注射法制作大鼠蛛网膜下腔出血模型；假手术组穿刺针插入视交叉池,但不注入血液；SAH+溶剂组注血后立刻和注血后1h分别向腹腔注射双蒸水0.5ml;SAH+Ghrelin组于注血后立刻和注血后1h分别向大鼠腹腔注射相应浓度Ghrelin水溶液0.5ml;SAH+Ghrelin+Ly294002组于注血前0.5h左侧脑室注射Ly294002溶液(50mmol/L溶于DMSO浓度为25%的磷酸盐缓冲液)10gL;各组分别于术后24小时采用Yamaguchi评分系统对大鼠神经功能缺损情况进行评分,并处死大鼠,干湿重比值法测大鼠脑含水量；TUNEL检测各实验组大鼠颞叶皮层神经元细胞凋亡情况；免疫荧光检测p-Akt在大鼠颞叶的表达;western blot检测各组大鼠颞叶p-Akt, caspase-3两种蛋白表达情况。结果在蛛网膜下腔出血后24小时Ghrelin可以明显改善大鼠的神经功能,减少神经细胞的凋亡以及减轻脑水肿。免疫荧光图片显示p-Akt的表达主要是在神经元内。Ghrelin的应用可以在蛛网膜下腔出血后激活神经元内PI3K/Akt信号通过路,促进神经元内p-Akt的表达,从而抑制下游caspase-3蛋白的表达而发挥神经保护作用的。Ghrelin的这种神经保护作用可以被PI3K/Akt信号通路的特异性抑制剂LY294002抑制。结论早期脑损伤是蛛网膜下腔出血预后不佳的重要原因之一,Ghrelin可以有效的减轻蛛网膜下腔出血后早期脑损伤,其机制可能是通过激活神经元内PI3K/Akt信号通路实现的。
[Abstract]:Objective the subarachnoid hemorrhage, especially the subarachnoid hemorrhage caused by aneurysm rupture, is a disease with high mortality and high disability. The stroke caused by subarachnoid hemorrhage, 5-7% of the total number of strokes, cerebral vasospasm, and early brain injury are two major complications that patients usually face in subarachnoid hemorrhage. The researchers focused their efforts on the study of cerebral vasospasm, which could be the main cause of poor prognosis in patients with subarachnoid hemorrhage. In order to prevent the two brain damage caused by cerebral vasospasm, the researchers carried out a lot of experiments and clinical trials, when cerebral vasospasm was very high. After good control, people have found that there is no good improvement in the prognosis of patients with subarachnoid hemorrhage. In recent years, it has been found that early brain damage (early brain injury EBI) may be an important cause of poor prognosis in subarachnoid hemorrhage patients. Finding effective treatment means that.Ghrelin is a polypeptide containing 28 amino acids. It is an endogenous ligand for the first growth hormone secretin found by human beings. It plays a broad biological role by combining with the growth hormone secretin receptor to promote the release of growth hormone. The circulating Ghrelin is mainly derived from the gastrointestinal tract. Most of them are secreted by the X/A cells of the gastric mucosa. Besides the gastrointestinal tract, Ghrelin is also widely distributed in the central nervous system and peripheral tissues of a variety of animals, such as the hypothalamus, the pituitary, the myocardium, the placenta and the testis, and so on. It is found that Ghrelin can play a neuroprotective function through a variety of mechanisms, while the P13K/Akt signaling pathway can be used. The protective effect of Ghrelin on early brain injury after subarachnoid hemorrhage in rats was observed and its protective mechanism was explored to provide new ideas and methods for clinical treatment of subarachnoid hemorrhage, especially early brain injury. 100 2 month old clean grade SD male rats and weight 250- in Fang method. 300g, randomly divided into 5 groups: (1) sham operation group (n=20); (2) SAH model group (n=20); (3) SAH+ solvent group (n=20); (4) SAH+Ghrelin group (n=20); (5) SAH+Ghrelin+Ly294002 group (n=20). The rat subarachnoid hemorrhage model was made by autologous blood optic cross pool injection; the puncture needle was inserted into the optic cross pool, but not the blood; SAH+ 0.5ml was injected into the abdominal cavity immediately after the blood injection of the solvent group and the 1H injected after the blood injection, and the group SAH+Ghrelin was injected with the corresponding concentration of 0.5ml in the abdominal cavity of the rats after the injection of blood and 1h after the injection of blood, respectively. The SAH+Ghrelin+Ly294002 group injected the Ly294002 solution in the left ventricle of 0.5h before the injection of blood (50mmol/L dissolved in the phosphate of DMSO concentration of 25%. Yamaguchi score system was used to score the nerve function defect in rats 24 hours after the operation, and the rats were killed and the rat brain water content was measured by the dry wet weight ratio method. TUNEL was used to detect the neuronal apoptosis in the temporal cortex of the rats in each experimental group; the expression of p-Akt in the temporal lobe of rats was detected by immunofluorescence; western Blot was used to detect the expression of p-Akt and caspase-3 two proteins in the temporal lobe of rats. Results in the 24 hours after subarachnoid hemorrhage Ghrelin could obviously improve the nerve function of rats, reduce the apoptosis of the nerve cells and reduce the brain edema. The expression of p-Akt is mainly in the application of.Ghrelin in the neuron. After the subomental hemorrhage, the PI3K/Akt signal in the neuron activates the signal through the neuron to promote the expression of p-Akt in the neuron, thus inhibiting the expression of the downstream caspase-3 protein and the neuroprotective effect of.Ghrelin, which can be suppressed by the specific inhibitor of the PI3K/Akt signaling pathway, LY294002. Conclusion early brain damage is a spider web. One of the important reasons for the poor prognosis of submembrane hemorrhage, Ghrelin can effectively reduce the early brain damage after subarachnoid hemorrhage, and its mechanism may be realized by activating the PI3K/Akt signal pathway in the neuron.
【学位授予单位】：第二军医大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R651.12

【相似文献】