P2x7受体依赖性微泡释放在大鼠颅脑外伤中的作用

发布时间：2018-07-04 23:38

本文选题：P2X7 + 微泡　；参考：《第二军医大学》2013年硕士论文

【摘要】：脑外伤(traumatic brain injury, TBI),也被称为颅脑损伤,是由外部机械力对大脑引发的脑组织损伤,如快速加速或减速运动,冲击波,压碎,弹丸冲击或穿透等外力均可造成。脑外伤可以引起一个短暂的或者永久的认知的障碍,身体损伤和心理疾病。脑外伤是全球范围内导致死亡和残疾的一个重要的原因,尤其是它在导致儿童和年轻人(45岁以下)的死亡和残疾的原因中位于榜首。事实上,每年全球范围内有10万人直接由于脑外伤而死亡或者住院,而目前估计有57万人正活在脑外伤后遗症中。脑外伤并不是一个单一的病理生理问题,而是一个复杂的疾病过程。由于直接损伤和继发性的损伤机制共同作用引起了身体结构的伤害和功能上的障碍。对于原发性的损伤直接发生在创伤产生的那个时刻,我们只能预防它。但持久的继发性损伤却给我们提供了一个可以进行干预治疗的窗口期。如果可以在治疗的窗口期内有效的预防或者降低继发性损伤,将会大大提高患者的长期治疗效果。但是,目前在临床上还并没有任何有效治疗脑外伤的药物转化成功。目前研究表明许多造成脑损伤后继发性损伤的原因,其中包括谷氨酸的兴奋毒性,细胞钙过载,自由基生成和脂质过氧化,线粒体功能障碍,炎性因子等。近年来ATP参与神经继发性损伤病理过程愈来愈受到人们的关注。高浓度ATP通过P2X7受体参与小胶质细胞激活,并通过微泡来介导参与1L—1β的释放。我们相信脑外伤后局部高浓度ATP可能参与继续性神经损伤。在本研究中,利用SD大鼠按照Marmarou的重物自由落体模型构建成TBI动物模型,然后通过给于P2X7受体的特异性拮抗剂A438079来抑制P2X7受体的功能,利用免疫荧光组化,蛋白印迹和Morris水迷宫等技术手段观察对TBI损伤的影响。结果发现,损伤区P2X7阳性的小胶质细胞明显活化转型为阿米巴状,其周围显示许多P2X7受体和Iba-1阳性的微泡。A438079和FTY720(免疫抑制剂,特性性微泡释放抑制剂)能够明显减少皮层损伤区的微泡的数量,降低局部神经细胞凋亡和神经元丢失和减轻了局部胶质化的程度；Western blot结果显示FTY720可抑制1L—1β的释放。在Morris水迷宫测试中,A438079也明显的减轻了TBI后的空间学习记忆能力下降的问题。上述结果表明TBI局部ATP通过P2X7受体参与了神经继发性损伤的病理过程,抑制P2X7受体可能会成为TBI治疗的新靶点。
[Abstract]:Brain injury (traumatic brain injury,), also known as brain injury, is caused by external mechanical forces, such as rapid acceleration or deceleration, shock wave, crushing, projectile impact or penetration. Brain trauma can cause a transient or permanent cognitive impairment, physical injury, and mental illness. Brain trauma is an important cause of death and disability worldwide, especially among the causes of death and disability among children and young people (under 45 years of age). In fact, 100000 people worldwide die or are hospitalized as a direct result of brain trauma every year, while an estimated 570000 are living with brain trauma sequelae. Traumatic brain injury is not a single pathophysiological problem, but a complex disease process. Both direct and secondary injury mechanisms lead to injury and dysfunction of the body structure. We can only prevent primary injury from occurring directly at the moment of trauma. But persistent secondary injuries provide a window for intervention. If the treatment window can effectively prevent or reduce secondary injury, will greatly improve the long-term efficacy of treatment. However, there has not been any effective drug conversion in the treatment of traumatic brain injury. Current studies have shown that many causes of secondary injury after brain injury, including glutamate excitotoxicity, cell calcium overload, free radical production and lipid peroxidation, mitochondrial dysfunction, inflammatory factors, and so on. In recent years, ATP involved in the pathological process of secondary nerve injury has attracted more and more attention. High concentration ATP participates in the activation of microglia through P2X _ 7 receptor, and participates in the release of 1L ~ (-1) 尾 through microbubbles. We believe that local high ATP concentration after brain injury may be involved in continuing nerve injury. In this study, a TBI animal model was constructed from SD rats according to Marmarou's weight free fall model, and then the function of P2X7 receptor was inhibited by giving a specific antagonist A438079 to P2X7 receptor, and immunofluorescence histochemistry was used. The effects of Western blot and Morris water maze on TBI injury were observed. The results showed that P2X7 positive microglia were activated and transformed into amoeba, and many P2X7 receptor and Iba-1 positive microvesicles. A438079 and FTY720 (immunosuppressant) were found around them. The results showed that FTY720 could significantly reduce the number of microbubbles in cortical injury area, decrease the apoptosis and loss of neurons and reduce the degree of local glial degeneration. Western blot results showed that FTY720 could inhibit the release of 1L-1 尾. In Morris water maze test, A438079 also significantly alleviated the problem of spatial learning and memory decline after TBI. These results suggest that ATP is involved in the pathological process of secondary nerve injury through P2X7 receptor in TBI, and the inhibition of P2X7 receptor may become a new target of TBI therapy.
【学位授予单位】：第二军医大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R651.15

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